among

PASS THROUGH TRUST AGREEMENT _____

Dated _________

among

UNION TANK CAR COMPANY

and

XXXXXX TRUST AND SAVINGS BANK,
as Pass Through Trustee

$________

______________
_______ Pass Through Trust
Pass Through Certificates,
Series _______

TABLE OF CONTENTS TO PASS THROUGH TRUST AGREEMENT _____

Section Page
------- ----
ARTICLE I

DEFINITIONS

SECTION 1.1. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SECTION 1.2. Compliance Certificates and Opinions . . . . . . . . . . . . . . . . . 12
SECTION 1.3. Form of Documents Delivered to Pass Through Trustee . . . . . . . . . 13
SECTION 1.4. Acts of Certificateholders. . . . . . . . . . . . . . . . . . . . . . 13

ARTICLE II

ACQUISITION OF EQUIPMENT NOTES AND ETCs;
ORIGINAL ISSUANCE OF CERTIFICATES

SECTION 2.1. Issuance of Certificates; Acquisition of Equipment Notes and ETCs . . 15
SECTION 2.2. Declaration of Trust; Acceptance By Pass Through Trustee . . . . . . . 18
SECTION 2.3. Limitation of Powers . . . . . . . . . . . . . . . . . . . . . . . . . 18
SECTION 2.4. Sale of Equipment Notes Under Certain Circumstances . . . . . . . . . 18

ARTICLE III

THE CERTIFICATES

SECTION 3.1. Form, Denomination and Execution of Certificates . . . . . . . . . . . 19
SECTION 3.2. Authentication of Certificates . . . . . . . . . . . . . . . . . . . . 20
SECTION 3.3. Temporary Certificates . . . . . . . . . . . . . . . . . . . . . . . . 20
SECTION 3.4. Registration of Transfer and Exchange of Certificates . . . . . . . . 20
SECTION 3.5. Mutilated, Destroyed, Lost or Stolen Certificates . . . . . . . . . . 21
SECTION 3.6. Persons Deemed Owners . . . . . . . . . . . . . . . . . . . . . . . . 21
SECTION 3.7. Cancellation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
SECTION 3.8. Limitation of Liability for Payments . . . . . . . . . . . . . . . . . 22
SECTION 3.9. Book-Entry and Registered Certificates . . . . . . . . . . . . . . . . 22

ARTICLE IV

DISTRIBUTIONS; STATEMENTS TO
CERTIFICATEHOLDERS

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Section Page
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SECTION 4.1. Certificate Account and Special Payments Account . . . . . . . . . . . 24
SECTION 4.2. Distribution from Certificate Account and Special Payments Account . . 25
SECTION 4.3. Statements to Certificateholders . . . . . . . . . . . . . . . . . . . 27
SECTION 4.4. Investment of Special Payment Money . . . . . . . . . . . . . . . . . 27

ARTICLE V

THE COMPANY

SECTION 5.1. Maintenance of Corporate Existence . . . . . . . . . . . . . . . . . . 28
SECTION 5.2. Consolidation, Merger or Sale of Assets Permitted . . . . . . . . . . 28

ARTICLE VI

DEFAULT

SECTION 6.1. Events of Default . . . . . . . . . . . . . . . . . . . . . . . . . . 29
SECTION 6.2. Incidents of Sale of Equipment Notes and ETCs . . . . . . . . . . . . 30
SECTION 6.3. Judicial Proceedings Instituted by Pass Through Trustee . . . . . . . 31
SECTION 6.4. Control by Certificateholders . . . . . . . . . . . . . . . . . . . . 31
SECTION 6.5. Waiver of Past Defaults . . . . . . . . . . . . . . . . . . . . . . . 32
SECTION 6.6. Undertaking to Pay Court Costs . . . . . . . . . . . . . . . . . . . . 33
SECTION 6.7. Right of Certificateholders to Receive Payments Not to Be Impaired . . 33
SECTION 6.8. Certificateholders May Not Bring Suit Except Under Certain
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
SECTION 6.9. Remedies Cumulative . . . . . . . . . . . . . . . . . . . . . . . . . 34

ARTICLE VII

THE PASS THROUGH TRUSTEE

SECTION 7.1. Certain Duties and Responsibilities . . . . . . . . . . . . . . . . . 34
SECTION 7.2. Notice of Defaults . . . . . . . . . . . . . . . . . . . . . . . . . . 35
SECTION 7.3. Certain Rights of Trustee . . . . . . . . . . . . . . . . . . . . . . 36
SECTION 7.4. Not Responsible for Recitals or Issuance of Certificates . . . . . . . 37
SECTION 7.5. May Hold Certificates . . . . . . . . . . . . . . . . . . . . . . . . 37
SECTION 7.6. Money Held in Pass Through Trust . . . . . . . . . . . . . . . . . . . 37
SECTION 7.7. Compensation and Reimbursement . . . . . . . . . . . . . . . . . . . . 38
SECTION 7.8. Corporate Trustee Required; Eligibility . . . . . . . . . . . . . . . 39
SECTION 7.9. Resignation and Removal; Appointment of Successor . . . . . . . . . . 40

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Section Page
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SECTION 7.10. Acceptance of Appointment by Successor . . . . . . . . . . . . . . . 41
SECTION 7.11. Merger, Conversion, Consolidation or Succession to Business. . . . . 42
SECTION 7.12. Maintenance of Agencies . . . . . . . . . . . . . . . . . . . . . . 42
SECTION 7.13. Money for Certificate Payments to Be Held in Pass Through Trust . . 44
SECTION 7.14. Registration of Equipment Notes and ETCs in Pass Through
Trustee's Name . . . . . . . . . . . . . . . . . . . . . . . . . . 44
SECTION 7.15. Representations and Warranties of Pass Through Trustee . . . . . . . 45
SECTION 7.16. Withholding Taxes; Information Reporting . . . . . . . . . . . . . . 45
SECTION 7.17. Trustee's Liens . . . . . . . . . . . . . . . . . . . . . . . . . . 46
SECTION 7.18. Preferential Collection of Claims . . . . . . . . . . . . . . . . . 46

ARTICLE VIII

CERTIFICATEHOLDERS' LISTS AND REPORTS BY PASS THROUGH TRUSTEE

SECTION 8.1. The Company to Furnish Pass Through Trustee with Names and
Addresses of Certificateholders. . . . . . . . . . . . . . . . . . 46
SECTION 8.2. Preservation of Information; Communications to Certificateholders . 47
SECTION 8.3. Reports by Pass Through Trustee . . . . . . . . . . . . . . . . . . 47
SECTION 8.4. Reports by the Company . . . . . . . . . . . . . . . . . . . . . . . 47

ARTICLE IX

SUPPLEMENTS TO PASS THROUGH TRUST AGREEMENT

SECTION 9.1. Supplements to Pass Through Trust Agreement Without Consent of
Certificateholders . . . . . . . . . . . . . . . . . . . . . . . . 48
SECTION 9.2. Supplements to Pass Through Trust Agreement with Consent of
Certificateholders . . . . . . . . . . . . . . . . . . . . . . . . 49
SECTION 9.3. Documents Affecting Immunity or Indemnity . . . . . . . . . . . . . 50
SECTION 9.4. Execution of Supplements to Pass Through Trust Agreements . . . . . 50
SECTION 9.5. Effect of Supplements to Pass Through Trust Agreement . . . . . . . 50
SECTION 9.6. Conformity with Trust Indenture Act . . . . . . . . . . . . . . . . 50
SECTION 9.7. Reference in Certificates to Supplements to Pass Through Trust
Agreements . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

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Section Page
------- ----
ARTICLE X

AMENDMENTS TO INDENTURE, NOTE DOCUMENTS,
EQUIPMENT TRUST AGREEMENTS AND ETC DOCUMENTS

ARTICLE XI

TERMINATION OF PASS THROUGH TRUST

ARTICLE XII

MISCELLANEOUS PROVISIONS

SECTION 12.1. Limitation on Rights of Certificateholders . . . . . . . . . . . . . . 52
SECTION 12.2. Certificates Nonassessable and Fully Paid . . . . . . . . . . . . . . 52
SECTION 12.3. Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
SECTION 12.4. Communication by Certificateholder with Other Certificateholders . . . 54
SECTION 12.5. Governing Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
SECTION 12.6. Severability of Provisions . . . . . . . . . . . . . . . . . . . . . . 54
SECTION 12.7. Trust Indenture Act Controls . . . . . . . . . . . . . . . . . . . . . 54
SECTION 12.8. Effect of Headings and Table of Contents . . . . . . . . . . . . . . . 55
SECTION 12.9. Successors and Assigns . . . . . . . . . . . . . . . . . . . . . . . . 55
SECTION 12.10. Benefits of Pass Through Trust Agreement . . . . . . . . . . . . . . . 55
SECTION 12.11. Legal Holidays . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
SECTION 12.12. Counterparts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Exhibit A - Form of Certificate
Exhibit B - Guarantee
Exhibit C - Form of DTC Letter of Representations
Schedule I - Description of Equipment Notes to be Issued under the Indenture
Schedule II - Description of ETCs to be Issued under Equipment Trust Agreements

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This PASS THROUGH TRUST AGREEMENT _______, dated __________, is made
with respect to the formation of the Union Tank Car Company ______ Pass Through
Trust, among UNION TANK CAR COMPANY, a Delaware corporation ("Union") and
XXXXXX TRUST AND SAVINGS BANK, an Illinois banking corporation, solely as Pass
Through Trustee and not in its individual capacity.

WITNESSETH:

[WHEREAS, a $_______ aggregate principal amount Equipment Trust
Certificate, Series ___ (together with the guarantee of Union to be endorsed
thereon, the "Union ETCs"), will be issued pursuant to an Equipment Trust
Agreement, dated ______ as may be amended or supplemented from time to time
(the "Union Equipment Trust Agreement"), between Union and ___________, as
trustee (the "Union Equipment Trust Trustee");]

[WHEREAS, the Union Equipment Trust Trustee will issue the Union ETCs
in connection with the financing of railway tank cars and other rail cars of
the type used in Union's business (the "Union Trust Equipment");

[WHEREAS, pursuant to the terms of this Pass Through Trust Agreement,
the Union Equipment Trust Agreement, the Union ETCs are to be sold upon their
issuance to the Pass Through Trustee, and the Pass Through Trustee shall
purchase the ETCs upon their issuance and shall hold such ETCs in trust for the
benefit of the Certificateholders;]

WHEREAS, a certain Owner Trustee, on behalf of a certain Owner
Participant, will purchase certain Equipment (as defined) from Union;

WHEREAS, the Owner Trustee will lease the Equipment to Union pursuant
to the Lease;

WHEREAS, such Owner Trustee will issue on a nonrecourse basis
Equipment Notes, under the Indenture, in order to finance not more than 80% of
the purchase price to be paid to Union for the Equipment subject to the Lease;

WHEREAS, pursuant to the terms and conditions of this Pass Through
Trust Agreement and the Participation Agreement, such agreements to be entered
into by the Pass Through Trustee contemporaneously with the execution and
delivery of this Pass Through Trust Agreement, certain Equipment Notes are to
be sold, from time to time, to the Pass Through Trustee, and the Pass Through
Trustee shall purchase, from time to time, such Equipment Notes and shall hold
such Equipment Notes in trust for the benefit of the Certificateholders;

WHEREAS, the Pass Through Trustee, upon execution and delivery of this
Pass Through Trust Agreement, hereby declares the creation of this Pass Through
Trust for the benefit of the Certificateholders, and the initial
Certificateholders as the grantors of the Pass Through Trust, by their
respective acceptances of the Certificates, join in the creation of this Pass
Through Trust with the Pass Through Trustee;

WHEREAS, to facilitate the sale of the [ETCs] [and] [certain Equipment
Notes] to the Pass Through Trustee and the purchase of such [ETCs] [and]
[Equipment Notes] by the Pass Through Trustee, Union has duly authorized the
execution and delivery of this Pass Through Trust Agreement as an "issuer", as
such term is defined in and solely for purposes of the Securities Act of 1933,
as amended, of the Certificates being issued hereunder and as an "obligor", as
such term is defined in and solely for purposes of the Trust Indenture Act of
1939, as amended, with respect to the Certificates and is undertaking to
perform certain administrative and ministerial duties hereunder and is also
undertaking to pay the fees and expenses of the Pass Through Trustee; and

WHEREAS, this Pass Through Trust Agreement is subject to the
provisions of the Trust Indenture Act of 1939, as amended, and shall, to the
extent applicable, be governed by such provisions;

NOW, THEREFORE, in consideration of the mutual agreements herein
contained, and of other good and valuable consideration the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows:

ARTICLE I

DEFINITIONS

SECTION 1.1. Definitions.

(a) For all purposes of this Pass Through Trust Agreement, except as
otherwise expressly provided or unless the context otherwise requires:

(i) the terms used herein that are defined in this Article
have the meanings assigned to them in this Article, and include the
plural as well as the singular;

(ii) all other terms used herein which are defined in the
Trust Indenture Act, either directly or by reference therein, have the
meanings assigned to them therein;

(iii) all references in this Pass Through Trust Agreement to
designated "Articles", "Sections" and other subdivisions are to the
designated Articles, Sections and other subdivisions of this Pass
Through Trust Agreement; and

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(iv) the words "herein", "hereof " and "hereunder" and other
words of similar import refer to this Pass Through Trust Agreement as
a whole and not to any particular Article, Section or other
subdivision.

(b) For all purposes of this Pass Through Trust Agreement, the
following capitalized terms have the following respective meanings:

"Act," with respect to any Certificateholder, has the meaning
specified in Section 1.4.

"Affiliate" of any Person shall mean any other Person which directly
or indirectly controls, or is controlled by, or is under a common control with,
such Person. The term "control", as used with respect to any Person, means the
possession, directly or indirectly, of the power to direct or cause the
direction of the management policies of such Person, whether through the
ownership of voting securities, by contract or otherwise; and the terms
"controlling" and "controlled" have meanings correlative to the foregoing.

"Authorized Agent" means any Paying Agent or Registrar.

"Avoidable Tax" has the meaning specified in Section 7.9(e).

"Book-Entry Certificates" means a beneficial interest in the
Certificates, ownership and transfers of which shall be made through book
entries by a Clearing Agency as described in Section 3.9.

"Business Day" means any day other than a Saturday or a Sunday or a
day on which commercial banking institutions or trust company are authorized or
required by law, regulation or executive order to be closed in New York, New
York, Chicago, Illinois or, so long as any Certificate is outstanding, a city
and state in which the respective Corporate Trust Office of the Owner Trustee,
the Pass Through Trustee, the Indenture Trustee, any Equipment Trust Trustee or
Paying Agent is located.

"Certificate" means any one of the certificates executed and
authenticated by the Pass Through Trustee, substantially in the form of Exhibit
A hereto.

"Certificate Account" means the account or accounts created and
maintained pursuant to Section 4.1(a).

"Certificateholder" means the Person in whose name a Certificate is
registered in the Register.

"Certificate Owner" means, when used in Section 3.9, the Person who
owns a Book Entry Certificate.

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"Clearing Agency" means an organization registered as a "clearing
agency" pursuant to Section 17A of the Securities Exchange Act of 1934, as
amended.

"Clearing Agency Participant" means a broker, dealer, bank, other
financial institution or other Person for whom from time to time a Clearing
Agency effects, directly or indirectly, book-entry transfers and pledges of
securities deposited with the Clearing Agency.

"Closing Date" means _______.

"Commission" means the Securities and Exchange Commission, as from
time to time constituted, created under the Securities Exchange Act of 1934,
or, if at any time after the execution of this instrument such Commission is
not existing and performing the duties now assigned to it under the Trust
Indenture Act, then the body performing such duties on such date.

"Company" means Union Tank Car Company, a Delaware corporation, or its
successors in interest pursuant to Section 5.2, or any other obligor with
respect to the Certificates (within the meaning of the Trust Indenture Act).

"Corporate Trust Office" means, with respect to the Pass Through
Trustee, any Equipment Trustee and the Indenture Trustee, the office of such
trustee in the city at which at any particular time its corporate trust
business shall be principally administered.

"De Minimis Certificate" has the meaning specified in Section 3.1.

"Direction" has the meaning specified in Section 1.4(c).

"Equipment" means, with respect to the ETCs, all of the Union Trust
Equipment, and with respect to the Equipment Notes, all of the Units covered by
the Lease; or as the context may require, all of the Equipment covered by the
ETCs and the Equipment Notes.

"Equipment Note" means any one of the Equipment Notes (as defined in
the Indenture) described on Schedule I attached hereto, including any Equipment
Note (as so defined) issued under the Indenture as a replacement or
substitution therefor, held by the Pass Through Trustee.

"Equipment Trust Agreement" means the Union Equipment Trust Agreement
dated ________, as such Equipment Trust Agreement may be amended or
supplemented from time to time in accordance with its terms.

"Equipment Trust Default" means, with respect to either Equipment
Trust Agreement, any Event of Default (as such term is defined in such
Equipment Trust Agreement).

"Equipment Trust Trustee" means the Union Equipment Trust Trustee.

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"ETC" means any one of the Equipment Trust Certificates described in
Schedule II attached hereto, including any ETC (as so defined) issued under the
applicable Equipment Trust Agreement as a replacement or substitution therefor,
held by the Pass Through Trustee.

"ETC Documents", with respect to an ETC, means the applicable
Equipment Trust Agreement.

"Guarantee" means the guarantee of Union set forth in Article XII
hereof and on each of the Certificates.

"Escrow Account" has the meaning specified in Section 2.1(b).

"Escrowed Funds" has the meaning specified in Section 2.1(b).

"Event of Default" means an event described in Section 6.1.

"Fractional Undivided Interest" means the undivided interest in the
Pass Through Trust that is evidenced by an Outstanding Certificate expressed as
a fraction of the total undivided interests in the Pass Through Trust
represented by all Outstanding Certificates.

"Indenture" means the Trust Indenture and Security Agreement (UTC
Trust No. _____) (___), dated _______, between the Owner Trustee and the
Indenture Trustee, as the Indenture may be amended or supplemented from time to
time in accordance with its terms. The term "Indenture" includes each
Indenture Supplement entered into pursuant to the terms of the Indenture.

"Indenture Default" means, with respect to the Indenture, any
Indenture Event of Default (as such term is defined in the Indenture).

"Indenture Trustee" means Xxxxxx Trust and Savings Bank, in its
capacity as indenture trustee under the Indenture, and any other Person which
may from time to time be acting as Indenture Trustee in accordance with the
provisions of the Indenture.

"Initial Cut-off Date" means _________.

"Issuance Date" means the date of the issuance of the Certificates.

"Lease" means the Equipment Lease Agreement (UTC Trust No. ______)
(____) with respect to the Equipment between the Owner Trustee, as the lessor,
and Union, as the lessee, as the Lease may be amended or supplemented from time
to time in accordance with its terms. Such term shall include each Lease
Supplement entered into pursuant to the terms of the Lease.

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"Lease Event of Default" means, with respect to the Lease, an Event of
Default under the Lease as specified in Section 14 thereof.

"Lease Supplement" has the meaning assigned to that term in the Lease.

"Letter of Representations" means the agreement among, the Pass
Through Trustee and the initial Clearing Agency substantially in the form
attached hereto as Exhibit C.

"Make-Whole Amount" has the meaning assigned to that term in the
Indenture.

"Note Documents," with respect to any Equipment Note, means the
Indenture, the Lease and the Participation Agreement.

"Officer's Certificate" means a certificate signed, (a) in the case of
the Company, by (i) the Treasurer, any Assistant Treasurer, the Controller or
any Assistant Controller of such Company, signing alone, or (ii) any Vice
President signing together with the Secretary, any Assistant Secretary, the
Treasurer or any Assistant Treasurer of such Company, or (b) in the case of the
Owner Trustee, an Equipment Trust Trustee or the Indenture Trustee, a
Responsible Officer of such Owner Trustee, Equipment Trust Trustee or Indenture
Trustee.

"Opinion of Counsel" means a written opinion of legal counsel, who (i)
in the case of counsel for the Company may be (A) a lawyer employed by the
Company, (B) Xxxx, Xxxxxx & Xxxxxxxxx, or (C) such other counsel designated by
the Company and reasonably acceptable to the Pass Through Trustee and (ii) in
the case of the Owner Trustee, any Equipment Trust Trustee or the Indenture
Trustee, such counsel as may be designated by any of them whether or not such
counsel is an employee of any of them, and who shall be acceptable to the Pass
Through Trustee.

"Outstanding," with respect to Certificates, means, as of the date of
determination, all Certificates theretofore authenticated and delivered under
this Pass Through Trust Agreement, except:

(i) Certificates theretofore canceled by the Registrar or
delivered to the Pass Through Trustee or the Registrar for
cancellation;

(ii) Certificates for which money in the full amount required
to make the final distribution payment to be made pursuant to Section
11.1
hereof has been theretofore deposited with the Pass Through
Trustee in trust for the Certificateholders as provided in Section 4.1
pending distribution of such money to the Certificateholders pursuant
to such final distribution payment; and

(iii) Certificates in exchange for or in lieu of which other
Certificates have been authenticated and delivered pursuant to this
Pass Through Trust Agreement.

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"Owner Participant" means the "Owner Participant" referred to in the
Participation Agreement and any permitted successor or assign of any such Owner
Participant.

"Owner Trustee," with respect to any Equipment Note or the Indenture
or the Lease, means _______________, not in its individual capacity but solely
as owner trustee of an owner trust for the benefit of the Owner Participant,
and each other Person which may from time to time be acting as Owner Trustee in
accordance with the provisions of the Note Documents.

"Participation Agreement" means the Participation Agreement (UTC Trust
No. ______) (____), dated _________, and to which the Pass Through Trustee, the
Owner Trustee, the Indenture Trustee, the Owner Participant, and Union are
parties, as the Participation Agreement may be amended or supplemented from
time to time in accordance with its respective terms.

"Pass Through Trust" means the trust created by this Pass Through
Trust Agreement, the estate of which consists of the Trust Property.

"Pass Through Trust Agreement" means this Pass Through Trust
Agreement, as it may be amended from time to time in accordance with the terms
hereof.

"Pass Through Trustee" means the institution executing this Pass
Through Trust Agreement as Pass Through Trustee, or its successor in interest,
and any successor trustee appointed as provided herein.

"Paying Agent" means the paying agent maintained and appointed
pursuant to Section 7.12.

"Permitted Investments" means each of (i) direct obligations of the
United States of America and agencies thereof; (ii) obligations fully
guaranteed by the United States of America; (iii) certificates of deposit
issued by, or bankers' acceptances of, or time deposits with, any bank, trust
company or national banking association incorporated or doing business under
the laws of the United States of America or one of the states thereof having
combined capital and surplus and retained earnings of at least $100,000,000,
having general obligations rated at least A1 by Xxxxx'x Investors Service, Inc.
or A+ by Standard & Poor's Corporation (but excluding any new investment as to
which there is a public announcement by the rating agency providing a rating
thereon that such rating is under consideration for a possible downgrade below
A1 or A+, as the case may be), including the Owner Trustee in its individual
capacity or the Indenture Trustee in its individual capacity if such conditions
are met; (iv) commercial paper of any holding company of a bank, trust company
or national banking association described in clause (iii); (v) bearer note
deposits with, or certificates of deposit issued by, or promissory notes of,
any subsidiary incorporated under the laws of Canada (or any province thereof)
of any bank, trust company or national banking association described in clause
(iii); (vi) commercial paper of company having a rating of A-l/P-l or better
assigned to such commercial paper by Standard & Poor's Corporation

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or Xxxxx'x Investors Service, Inc. (or, if neither such organization shall
rate such commercial paper at any time, by any nationally recognized rating
organization in the United States of America); (vii) U.S. dollar-denominated
certificates of deposit issued by, or time deposits with, the European
subsidiaries of any bank, trust company or national banking association
described in clause (iii); (viii) Canadian Treasury Bills fully hedged to U.S.
dollars; (ix) bonds, notes or other obligations of any state of the United
States of America, or any political subdivision of any such state, or any
agencies or other instrumentalities of any such state, including, but not
limited to, industrial development bonds, pollution control revenue bonds,
public power bonds, housing bonds, other revenue bonds or any general
obligation bonds; provided that, at the time of their purchase, such
obligations are rated in the highest rating category by Standard & Poor's
Corporation or Xxxxx'x Investors Service, Inc. (or, if neither such
organization shall rate such obligations at such time, by any nationally
recognized rating organization in the United States of America); or (x) bonds
or other debt instruments of any company, if such bonds or other debt
instruments, at the time of their purchase, are rated in the highest rating
category by Standard & Poor's Corporation or Xxxxx'x Investors Service, Inc.
(or, if neither such organization shall rate such obligations at such time, by
any nationally recognized rating organization in the United States of America);
provided that no investment shall be eligible as and included within the
definition of the term "Permitted Investment" unless either (x) the final
maturity or date of return of such investment is equal to one year or less from
the date of purchase thereof, or (y) in the case of any investment referred to
in the foregoing clause (i) or (ii) only, such investment has a final maturity
or date of return greater than one year from the date of purchase thereof and
closing prices on a national securities exchange or bid and asked prices,
closing prices or yields to maturity for such investment are reported in The
Wall Street Journal (or if The Wall Street Journal is not at the time published
or ceases to report such prices, such prices are reported by any other
publication of nationally recognized standing of general circulation in New
York City).

"Person" means any individual, corporation, partnership, joint
venture, association, joint stock company, trust, unincorporated organization,
or government or any agency or political subdivision thereof.

"Pool Balance" means, as of any date, the aggregate unpaid principal
amount of the ETCs and the Equipment Notes held in the Pass Through Trust on
such date plus the amount of the principal payments on the ETCs and the
Equipment Notes held by the Pass Through Trustee and not yet distributed plus
the amount of any moneys held in the Escrow Account (other than earnings
thereon). The Pool Balance as of any Regular Distribution Date or Special
Distribution Date shall be computed after giving effect to the payment of
principal, if any, on the Equipment Notes held in the Pass Through Trust and
distribution thereof to be made on that date.

"Pool Factor" means, as of any date, the quotient (rounded to the
seventh decimal place) computed by dividing (i) the Pool Balance by (ii) the
aggregate original principal amount of the Certificates issued under the Pass
Through Trust. The Pool Factor as of any Regular Distribution Date or Special
Distribution Date shall be computed after giving effect to the payment of

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principal, if any, on the ETCs and the Equipment Notes held in the Pass Through
Trust and distribution thereof to be made on that date.

"Postponed Notes" means the Equipment Notes or ETCs as to which a
Postponement Notice shall have been delivered pursuant to Section 2.1(b).

"Postponement Notice" means a certificate of Union signed by an
officer of Union (i) requesting that the Pass Through Trustee execute and
deliver the Participation Agreement but temporarily postpone payment of the
purchase price of the Equipment Notes or ETCs to a date later than the Issuance
Date, (ii) identifying the amount of the purchase price of each Equipment Note
or ETC and the aggregate purchase price of all such Equipment Notes or ETCs,
(iii) setting forth the reasons for such postponement and (iv) with respect to
the Participation Agreement referred to in clause (i), either (A) setting or
resetting a new Closing Date (which shall be on or prior to the Initial Cut-off
Date) for payment by the Pass Through Trustee of such purchase price and
issuance of the Equipment Note or ETC, or (B) indicating that such new Closing
Date (which shall be on or prior to the Initial Cut-Off Date) will be set by
subsequent written notice not less than one Business Day prior to such new
Closing Date.

"Record Date" means the Business Day preceding a Regular Distribution
Date or a Special Distribution Date, as applicable.

"Register" has the meaning specified in Section 3.4.

"Registered Certificates" has the meaning specified in Section 3.1.

"Registrar" has the meaning specified in Section 3.4.

"Regular Distribution Date" means, with respect to distributions of
Scheduled Payments, _______ and _______ of each year, commencing on __________,
until payment of all the Scheduled Payments to be made under the Equipment
Notes and the ETCs has been made.

"Request" means a request by Union, setting forth the subject matter
of the request accompanied by an Officer's Certificate and an Opinion of
Counsel as provided in Section 1.2 of this Pass Through Trust Agreement.

"Responsible Officer" means (i) with respect to the initial Pass
Through Trustee, any initial Equipment Trust Trustee or the initial Indenture
Trustee, any officer in the Corporate Trust Office or any other office at which
the Pass Through Trustee, any Equipment Trust Trustee or the Indenture Trustee
conducts corporate trust business; and (ii) with respect to any successor Pass
Through Trustee, successor Equipment Trust Trustee, successor Indenture Trustee
or the Owner Trustee, the chairman or vice-chairman of the board of directors
or trustees, the chairman or vice-chairman of the executive or standing
committee of the board of directors or trustees, the

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president, the chairman of the committee on trust matters, any vice-president,
any second vice-president, the secretary, any assistant secretary, the
treasurer, any assistant treasurer, the cashier, any assistant cashier, any
trust officer or assistant trust officer, the comptroller and any assistant
comptroller. Responsible Officer also means, with respect to the Pass Through
Trustee, any Equipment Trust Trustee, the Indenture Trustee and the Owner
Trustee, any other officer of the Pass Through Trustee, the Owner Trustee, such
Equipment Trust Trustee or the Indenture Trustee customarily performing
functions similar to those performed by the persons who at the time shall be
any of the above designated officers, and with respect to a particular
corporate trust matter, any other officer to whom such matter is referred
because of his knowledge of and familiarity with the particular subject.

"Scheduled Payment" means, with respect to a Regular Distribution
Date, any payment (other than a Special Payment) of interest on or principal of
and interest on: (i) an Equipment Note due from the Owner Trustee which issued
such Equipment Note, which payment represents the installment of principal at
the stated maturity of such installment of principal on such Equipment Note, or
the payment of regularly scheduled interest accrued on the unpaid principal
amount of such Equipment Note, or both, to be made on such Regular Distribution
Date pursuant to the terms of such Equipment Note; or (ii) an ETC, to be made
on such Regular Distribution Date pursuant to the terms of such ETC.

"Special Distribution Date" means (i) in the case of prepayments with
respect to a voluntary termination of the Lease, the purchase of any Units by
Union pursuant to Section 22.1 of the Lease or an ordinary Event of Loss under
the Lease, on a Regular Distribution Date, (ii) in the case of prepayments with
respect to a Multiple Loss under the Lease, a refunding or refinancing of the
Equipment Notes or a purchase of the Equipment by Union from an Owner Trustee
of a competitor Owner Participant, on any Business Day following 15 days notice
from the Pass Through Trustee to The Depository Trust Company and (iii) in the
case of payments received following a default in respect of any Equipment Note,
on the second day of any month, and (iv) with respect to an ETC, the earliest
day of a month for which it is practicable for the Pass Through Trustee to give
notice pursuant to Section 4.2(c) 20 days prior thereto.

"Special Payment" means (i) with respect to an Equipment Note (or
portion thereof), any payment of principal of, Make-Whole Amount, if any, and
interest on such Equipment Note (or portion thereof) resulting from the
prepayment of such Equipment Note (or portion thereof) pursuant to Section 2.10
of the applicable Indenture, (ii) with respect to an Equipment Note, any
payment of principal of and interest (including any interest accruing upon
default) on, or any other amount in respect of, such Equipment Note upon an
Indenture Default in respect thereof, including payments received on account of
the purchase by the Owner Trustee of such Equipment Notes, (iii) the amounts
required to be distributed pursuant to the fifth paragraph of Section 2.1(b),
(iv) any proceeds from the sale of any Equipment Note by the Pass Through
Trustee pursuant to Article VI hereof; (v) with respect to an ETC, any payment
of principal of and interest (including any interest accruing upon default) on,
or any other amount in respect of,

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such ETC upon an Equipment Trust Default in respect thereof or upon an
acceleration under the Equipment Trust Agreement relating to such ETC, or (vi)
any proceeds from the sale of an ETC by the Pass Through Trustee pursuant to
Article VI hereof; and "Special Payments" means all of such Special Payments.

"Special Payments Account" means the account or accounts created and
maintained pursuant to Section 4.1(b).

"Specified Investments" means (i) direct obligations of the United
States of America and agencies thereof for which the full faith and credit of
the United States of America is pledged, (ii) obligations fully guaranteed by
the United States of America, (iii) certificates of deposit issued by, or
bankers' acceptances of, or time deposits (including overnight deposits) with,
any bank, trust company or national banking association incorporated or doing
business under the laws of the United States of America or one of the States
thereof having combined capital and surplus and retained earnings of at least
$500,000,000 (including the Indenture Trustee or Owner Trustee, in their
respective individual capacities, if such conditions are met), (iv) commercial
paper of company, banks, trust company or national banking associations
incorporated or doing business under the laws of the United States of America
or one of the States thereof and in each case having a rating of A-l/P-l or
better assigned to such commercial paper by Standard & Poor's Corporation or
Xxxxx'x Investors Service, Inc. (or, if neither such organization shall rate
such commercial paper at any time, by any nationally recognized rating
organization in the United States of America) and (v) repurchase agreements
with any financial institution described in clause (iii) above having a
combined capital and surplus of at least $750,000,000 fully collateralized by
obligations of the type described in clauses (i) through (iv) above; provided,
however, that if all of the above investments are unavailable, the entire
amount to be invested may be used to purchase Federal Funds from an entity
described in clause (iii) above; and provided further that no investment shall
be eligible as a "Specified Investment" unless the final maturity or date of
return of such investment occurs no later than _______.

"Subsequent Cut-off Date" means __________.

"Trust Indenture Act" means, except as otherwise provided in Section
9.6, the Trust Indenture Act of 1939 as in force at the date as of which this
instrument was executed.

"Trust Property" means the Union ETCs, the Guarantee and the Equipment
Notes held as the property of the Pass Through Trust and all moneys at any time
paid thereon and all moneys due and to become due thereunder, funds from time
to time deposited in the Escrow Account (other than earnings on Specified
Investments), the Certificate Account and the Special Payments Account and any
proceeds from the sale by the Pass Through Trustee pursuant to Article VI
hereof of any Equipment Note.

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"Trustee's Liens" means any Lien (within the meaning specified in
Appendix A to the Participation Agreement) arising as a result of (a) any claim
against the Pass Through Trustee or Xxxxxx Trust and Savings Bank, in its
individual capacity, respectively, not resulting from the actions contemplated
by the Operative Agreements (within the meaning specified in Appendix A to the
Participation Agreement), (b) the gross negligence or willful misconduct of, or
the falsity or inaccuracy of any representation or warranty of the Pass Through
Trustee or Xxxxxx Trust and Savings Bank, in their individual capacities,
respectively, (c) any claim against the Pass Through Trustee or Xxxxxx Trust
and Savings Bank, in their individual capacities, respectively, with respect to
Taxes (within the meaning specified in Appendix A to the Participation
Agreement) or Transaction Costs (within the meaning specified in Appendix A to
the Participation Agreement) against which Union is not required to indemnify
the Pass Through Trustee or Xxxxxx Trust and Savings Bank, in their individual
capacities, respectively, pursuant to the Participation Agreement or (d) any
claim arising out of any transfer by the Pass Through Trustee, of all or any
portion of its interests in the Equipment, the Trust Property or the Operative
Agreements other than the transfer of title to or possession of any Equipment
by the Pass Through Trustee pursuant to and in accordance with the applicable
Equipment Trust Agreement or the Indenture or pursuant to the exercise of the
remedies set forth in the Lease; provided, however, that any Trustee Lien which
is attributable solely to the Pass Through Trustee or Xxxxxx Trust and Savings
Bank, in their individual capacities, respectively, and would otherwise
constitute a Trustee Lien shall not constitute a Trustee Lien so long as (i)
the existence of such Trustee Lien poses no material risk of the sale,
forfeiture or loss of any Unit or any interest therein, including Equipment
Notes, (ii) the existence of such Trustee Lien does not interfere in any way
with the quiet enjoyment of any Unit by Union, as lessee and (iii) the Pass
Through Trustee or Xxxxxx Trust and Savings Bank, in their individual
capacities, respectively, is diligently contesting such Trustee Lien by
appropriate proceedings.

"Unit" has the meaning assigned to that term in the Lease.

"Union Equipment Trust Trustee" means ____________, in its capacity as
trustee under the Union Equipment Trust Agreement, and any other Person which
may from time to time be acting as Equipment Trust Trustee in accordance with
the provisions of the Union Equipment Trust Agreement.

SECTION 1.2. Compliance Certificates and Opinions. Upon any
application or request by Union to the Pass Through Trustee to take any action
under any provision of this Pass Through Trust Agreement, Union shall furnish
to the Pass Through Trustee an Officer's Certificate stating that, in the
opinion of the signers, all conditions precedent, if any, provided for in this
Pass Through Trust Agreement relating to the proposed action have been complied
with and an Opinion of Counsel stating that in the opinion of such counsel all
such conditions precedent, if any, have been complied with, except that in the
case of any such application or request as to which the furnishing of such
documents is specifically required by any provision of this Pass Through Trust

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Agreement relating to such particular application or request, no additional
certificate or opinion need be furnished.

Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Pass Through Trust Agreement (other
than a certificate provided pursuant to Section 8.4(d)) shall include:

(i) a statement that each individual signing such certificate
or opinion has read such covenant or condition and the definitions
herein relating thereto;

(ii) a brief statement as to the nature and scope of the
examination or investigation upon which the statements or opinions
contained in such certificate or opinion are used;

(iii) a statement that, in the opinion of each such
individual, he or she has made such examination or investigation as
necessary to enable him or her to express an informed opinion as to
whether or not such covenant or condition has been complied with; and

(iv) a statement as to whether or not, in the opinion of each
such individual, such condition or covenant has been complied with.

SECTION 1.3. Form of Documents Delivered to Pass Through Trustee. In
any case where several matters are required to be certified by, or covered by
an opinion of, any specified Person, it is not necessary that all such matters
be certified by, or covered by the opinion of, only one such Person, or that
they be so certified or covered by only one document, but one such Person may
certify or give an opinion with respect to some matters and one or more other
such Persons as to other matters and any such Person may certify or give an
opinion as to such matters in one or several documents.

Any Opinion of Counsel stated to be based on the opinion of other
counsel shall be accompanied by a copy of such other opinion.

Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Pass Through Trust Agreement, they may, but need not, be
consolidated and form one instrument.

SECTION 1.4. Acts of Certificateholders.

(a) Any direction, consent, waiver or other action provided by this
Pass Through Trust Agreement to be given or taken by Certificateholders may be
embodied in and evidenced by one or more instruments of substantially similar
tenor signed by such Certificateholders in person or by an agent duly appointed
in writing; and, except as herein otherwise expressly provided, such action
shall become effective when such instrument or instruments are delivered to the
Pass

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Through Trustee and, where it is hereby expressly required, to Union, any
Equipment Trust Trustee or the Indenture Trustee. Such instrument or
instrument (and the action embodied therein and evidenced thereby) are herein
sometimes referred to as the "Act" of the Certificateholders signing such
instrument or instruments. Proof of execution of any such instrument or of a
writing appointing any such agent shall be sufficient for any purpose of this
Pass Through Trust Agreement and conclusive in favor of the Pass Through
Trustee, Union, any Equipment Trust Trustee and the Indenture Trustee, if made
in the manner provided in this Section.

(b) The fact and date of the execution by any Person of any such
instrument or writing may be proved by the certificate of any notary public or
other officer of any jurisdiction authorized to take acknowledgments of deeds
or administer oaths that the Person executing such instrument acknowledged to
him the execution thereof, or by an affidavit of a witness to such execution
sworn to before any such notary or such other officer and where such execution
is by an officer of a corporation or association or a member of a partnership,
on behalf of such corporation, association or partnership, such certificate or
affidavit shall also constitute sufficient proof of his authority. The fact
and date of the execution of any such instrument or writing, or the authority
of the Person executing the same, may also be proved in any other reasonable
manner which the Pass Through Trustee deems sufficient. In the absence of bad
faith on the part of the Pass Through Trustee, an Officer's Certificate may be
deemed to be conclusively proved.

(c) In determining whether the Certificateholders of the requisite
Fractional Undivided Interests of Certificates Outstanding have given any
direction, consent or waiver (a "Direction"), under this Pass Through Trust
Agreement, Certificates owned by Union, the Owner Trustee, the Owner
Participant or any Affiliate of any such Person shall be disregarded and deemed
not to be Outstanding under this Pass Through Trust Agreement for purposes of
any such determination. In determining whether the Pass Through Trustee shall
be protected in relying upon any such Direction, only Certificates which the
Pass Through Trustee knows to be so owned shall be so disregarded.
Notwithstanding the foregoing, (i) if any such Person owns 100% of the
Certificates Outstanding, such Certificates shall not be so disregarded as
aforesaid, and (ii) if any amount of Certificates so owned by any such Person
have been pledged in good faith, such Certificates shall not be disregarded as
aforesaid if the pledgee establishes to the satisfaction of the Pass Through
Trustee the pledgee's right so to act with respect to such Certificates and
that the pledgee is not either of the Company, the Owner Trustee, the Pass
Through Trustee, the Owner Participant or any Affiliate of any such Person.

(d) Union, on behalf of the Company, may at its option by delivery of
an Officer's Certificate to the Pass Through Trustee set a record date to
determine the Certificateholders entitled to give any consent, request, demand,
authorization, direction, notice, waiver or other Act. Notwithstanding Section
316(c) of the Trust Indenture Act, such record date shall be the record date
specified in such Officer's Certificate which shall be a date not more than 30
nor less than 15 days prior to the first solicitation of Certificateholders in
connection therewith. If such a record date is fixed, such consent, request,
demand, authorization, direction, notice, waiver or

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other Act may be given before or after such record date, but only the
Certificateholders of record at the close of business on such record date shall
be deemed to be Certificateholders for the purposes of determining whether
Certificateholders of the requisite proportion of Outstanding Certificates have
authorized or agreed or consented to such consent, request, demand,
authorization, direction, notice, waiver or other Act, and for that purpose the
Outstanding Certificates shall be computed as of such record date; provided
that no such consent, request, demand, authorization, direction, notice, waiver
or other act by the Certificateholders on such record date shall be deemed
effective unless it shall become effective pursuant to the provisions of this
Agreement not later than one year after the record date.

(e) Any direction, consent, waiver or other action by the
Certificateholder of any Certificate shall bind the Certificateholder of every
Certificate issued upon the transfer thereof or in exchange thereof or in lieu
thereof, whether or not notation of such action is made upon such Certificate.

(f) Except as otherwise provided in Section 1.4(c), Certificates
owned by or pledged to any Person shall have an equal and proportionate benefit
under the provisions of this Pass Through Trust Agreement, without preference,
priority, or distinction as among all of the Certificates.

ARTICLE II

ACQUISITION OF EQUIPMENT NOTES AND ETCs;
ORIGINAL ISSUANCE OF CERTIFICATES

SECTION 2.1. Issuance of Certificates; Acquisition of Equipment Notes
and ETCs.

(a) Upon request of Union, the Pass Through Trustee shall execute,
authenticate and deliver Certificates with an aggregate principal amount
equalling the aggregate principal amount of the Equipment Notes and ETCs, as
the case may be, to be purchased by the Pass Through Trustee pursuant to the
Equipment Trust Agreements, this Pass Through Trust Agreement and the
Participation Agreement and evidencing the entire ownership of the Pass Through
Trust. The Pass Through Trustee, not in its individual capacity but solely as
Pass Through Trustee, shall issue and sell such Certificates, in authorized
denominations and in such Fractional Undivided Interests, so as to result in
the receipt of consideration in an amount equal to the aggregate principal
amount of the Equipment Notes and ETCs to be issued from time to time, as
contemplated by the Participation Agreement and the Equipment Trust Agreements,
respectively, and, concurrently therewith, the Pass Through Trustee shall
purchase, in the case of the Equipment Notes pursuant to the terms and
conditions of the Participation Agreement, the Equipment Notes (except
Postponed Notes, if any) then issued and, in the case of the ETCs pursuant to
the terms and conditions of the Union Equipment Trust Agreement, the ETCs
(except

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Postponed Notes, if any) then issued, at a purchase price equal to the amount
of consideration received by the Pass Through Trustee with respect to such
Equipment Notes and ETCs, respectively. Upon the issuance after the Issuance
Date of any Equipment Notes and Union ETCs not previously purchased by the Pass
Through Trustee, the Pass Through Trustee shall purchase at such time such
Equipment Notes and Union ETCs at a purchase price equal to the amount of
consideration received by the Pass Through Trustee with respect to such
Equipment Notes and Union ETCs. Except as provided in Sections 3.4 and 3.5
hereof, the Pass Through Trustee shall not execute, authenticate or deliver
Certificates in excess of the aggregate amount specified in this paragraph.
The provisions of this Subsection (a) are subject to the provisions of
Subsections (b) and (c) below.

(b) If Union shall deliver to the Pass Through Trustee on or prior
to the Issuance Date a Postponement Notice, the Pass Through Trustee shall
postpone the purchase of the Equipment Notes or ETCs (the "Postponed Notes")
referred to in such Postponement Notice and shall promptly deposit into an
escrow account (the "Escrow Account") an amount equal to the purchase price of
such Postponed Notes (the "Escrowed Funds"). The Escrowed Funds so deposited
into the Escrow Account shall be invested by the Pass Through Trustee at the
written direction and risk of, and for the benefit of, Union in Specified
Investments maturing (i) no later than the Initial Cut-off Date or (ii) if
Union has given notice to the Pass Through Trustee that the Postponed Notes
will not be issued, on the next Special Distribution Date, if such investments
are reasonably available for purchase. The Pass Through Trustee shall make
withdrawals from the Escrow Account only as provided in this Pass Through Trust
Agreement. An account statement delivered by the Pass Through Trustee to Union
shall be deemed written confirmation by Union that the investment transactions
identified therein accurately reflect the investment directions given to the
Pass Through Trustee by Union, unless Union notifies the Pass Through Trustee
in writing to the contrary within thirty (30) days of receipt of such
statement.

The Pass Through Trustee shall hold all Specified Investments until
the maturity thereof and will not sell or otherwise transfer such Specified
Investments. If Specified Investments held in the Escrow Account mature prior
to the Initial Cut-off Date, any proceeds received on the maturity of such
Specified Investments (other than any earnings thereon) shall be reinvested by
the Pass Through Trustee at the written direction and risk of, and for the
benefit of, Union in Specified Investments maturing (i) no later than the
Initial Cut-off Date or (ii) if Union has given notice to the Pass Through
Trustee that the Postponed Notes will not be issued, on the next Special
Distribution Date, if such investments are reasonably available for purchase.

Any earnings on Specified Investments received from time to time by
the Pass Through Trustee shall be promptly distributed to Union to an account
specified in writing by Union. Union shall pay to the Pass Through Trustee for
deposit to the Escrow Account an amount equal to any losses on Specified
Investments as incurred.

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On or prior to the Initial Cut-off Date, upon the written request of
Union and the satisfaction of the closing conditions specified in the
Participation Agreement and the Union Equipment Trust Agreement, as the case
may be, the Pass Through Trustee shall purchase the Postponed Notes with the
Escrowed Funds. The purchase price shall equal the principal amount of such
Postponed Notes.

If any of the Postponed Notes will not be issued on or prior to the
Initial Cut-off Date for any reason, Union shall so notify the Pass Through
Trustee and Union shall pay to the Pass Through Trustee on _______ for deposit
in the Special Payments Account, in immediately available funds, an amount
equal to the interest that would have accrued on such Postponed Notes at a rate
or rates equal to the interest rate or rates applicable to the Certificates
issued under the Pass Through Trust from the Issuance Date to, but not
including, ______ and the Pass Through Trustee shall transfer an amount equal
to that amount of Escrowed Funds that would have been used to purchase such
Postponed Notes and the amount paid by Union under this paragraph to the
Special Payments Account for distribution as a Special Payment in accordance
with the provisions hereof.

(c) Notwithstanding the foregoing Subsection (b), with respect to
amounts received by the Pass Through Trustee for the purchase of Equipment
Notes and Union ETCs to be issued after the Initial Cut-off Date pursuant to
the terms and conditions of the Participation Agreement or the Union Equipment
Trust Agreement, the Pass Through Trustee shall promptly deposit into the
Escrow Account an amount equal to the purchase price of such Equipment Notes or
Union ETCs. The Escrowed Funds so deposited into the Escrow Account shall be
invested by the Pass Through Trustee at the written direction and risk of, and
for the benefit of, Union in Specified Investments maturing (i) no later than
the Subsequent Cut-off Date or (ii) if Union has given notice to the Pass
Through Trustee that the aforementioned Equipment Notes or Union ETCs will not
be issued, on the next Special Distribution Date, if such investments are
reasonably available for purchase. The Pass Through Trustee shall make
withdrawals from the Escrow Account only as provided in this Pass Through Trust
Agreement. An account statement delivered by the Pass Through Trustee to Union
shall be deemed written confirmation by Union that the investment transactions
identified therein accurately reflect the investment directions given to the
Pass Through Trustee by Union, unless Union notifies the Pass Through Trustee
in writing to the contrary within thirty (30) days of receipt of such
statement.

The Pass Through Trustee shall hold all Specified Investments until
the maturity thereof and will not sell or otherwise transfer such Specified
Investments. If Specified Investments held in the Escrow Account mature prior
to the Subsequent Cut-off Date, any proceeds received on the maturity of such
Specified Investments (other than any earnings thereon) shall be reinvested by
the Pass Through Trustee at the written direction and risk of, and for the
benefit of, Union in Specified Investments maturing (i) no later than the
Subsequent Cut-off Date or (ii) if Union has given notice to the Pass Through
Trustee that the aforementioned Equipment Notes or Union

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ETCs will not be issued, on the next Special Distribution Date, if such
investments are reasonably available for purchase.

On or prior to the Subsequent Cut-off Date, upon the written request
of Union and the satisfaction of the closing conditions specified in the
Participation Agreement and the Union Equipment Trust Agreement, the Pass
Through Trustee shall purchase the applicable Equipment Notes and Union ETCs
with the Escrowed Funds. The purchase price shall equal the principal amount
of such Postponed Notes.

If any of the applicable Equipment Notes or Union ETCs will not be
issued on or prior to the Subsequent Cut-off Date for any reason, Union shall
so notify the Pass Through Trustee and Union shall pay to the Pass Through
Trustee on _______ for deposit in the Special Payments Account, in immediately
available funds, an amount equal to the interest that would have accrued on
such Equipment Notes or Union ETCs, as the case may be, at a rate or rates
equal to the interest rate or rates applicable to the Certificates issued under
the Pass Through Trust from the Issuance Date to, but not including, ________
and the Pass Through Trustee shall transfer an amount equal to that amount of
Escrowed Funds that would have been used to purchase such Equipment Notes or
Union ETCs and the amount paid by Union under this paragraph to the Special
Payments Account for distribution as a Special Payment in accordance with the
provisions hereof.

SECTION 2.2. Declaration of Trust; Acceptance By Pass Through Trustee.
The Pass Through Trustee, upon the execution and delivery of this Pass Through
Trust Agreement, acknowledges its acceptance of all right, title, and interest
in and to the Equipment Notes and the ETCs, as the case may be, acquired
pursuant to Section 2.1 hereof and, in the case of the Equipment Notes, the
Participation Agreement, and declares that the Pass Through Trustee holds and
will hold such right, title, and interest, together with all other property
constituting the Trust Property, for the benefit of all present and future
Certificateholders, upon the trusts herein set forth. By its payment for and
acceptance of each Certificate issued to it hereunder, each initial
Certificateholder as grantor of the Trust thereby joins in the creation and
declaration of the Trust.

SECTION 2.3. Limitation of Powers. The Pass Through Trust is
constituted solely for the purpose of making the investment in the Equipment
Notes and the ETCs, and, except as set forth herein, the Pass Through Trustee
is not authorized or empowered to acquire any other investments or engage in
any other activities and, in particular, the Pass Through Trustee is not
authorized or empowered to do anything that would cause the Pass Through Trust
to fail to qualify as a "grantor trust" for federal income tax purposes
(including as subject to this restriction,

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acquiring any Equipment (as defined in the Indenture) by bidding the Equipment
Notes, the ETCs or otherwise, or taking any action with respect to any such
Equipment once acquired).

SECTION 2.4. Sale of Equipment Notes Under Certain Circumstances. If
Union elects, in accordance with Section 10.2 of the Participation Agreement,
to refund or refinance Equipment Notes, the Pass Through Trustee shall, upon
satisfaction of the conditions set forth in Section 10.2 of the Participation
Agreement, transfer such Equipment Notes to the Person designated by Union and
will take any other action reasonably required to effect such refunding.

ARTICLE III

THE CERTIFICATES

SECTION 3.1. Form, Denomination and Execution of Certificates. The
Certificates shall be issued in fully registered form without coupons and shall
be substantially in the form attached hereto as Exhibit A, together with the
Guarantee of Union attached thereto in substantially the form attached hereto
as Exhibit B, with such omissions, variations and insertions as are permitted
by this Pass Through Trust Agreement, and may have such letters, numbers or
other marks of identification and such legends or endorsements printed,
lithographed, typewritten or engraved thereon, as may be required to comply
with the rules of any securities exchange on which the Certificates may be
listed or to conform to any usage in respect thereof, or as may, consistently
herewith, be prescribed by the Pass Through Trustee or by the officer executing
such Certificates, such determination by such officer to be evidenced by his or
her signing of the Certificates.

Except as provided in Section 3.9, the definitive Certificates (the
"Registered Certificates") shall be printed, lithographed, typewritten or
engraved or produced by any combination of these methods or may be produced in
any other manner permitted by the rules of any securities exchange on which the
Certificates may be listed, all as determined by the officer executing such
Certificates, as evidenced by his execution of such Certificates.

The Certificates shall be issued in minimum denominations of $1,000 or
any integral multiple of $1,000 in excess thereof, except that one Certificate
may be issued in a denomination of less than $1,000 (the "De Minimis
Certificate").

The Certificates shall be executed on behalf of the Pass Through
Trustee by manual or facsimile signature of a Responsible Officer of the Pass
Through Trustee. Certificates bearing the manual or facsimile signature of an
individual who was, at the time when such signature was affixed, authorized to
sign on behalf of the Pass Through Trustee shall be valid and binding
obligations of the Pass Through Trustee, notwithstanding that such individual
has ceased to be so authorized prior to the authentication and delivery of such
Certificates or did not hold such office at the date of such Certificates. No
Certificate shall be entitled to any benefit under this Pass

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Through Trust Agreement, or be valid for any purpose, unless there appears on
such Certificate a certificate of authentication substantially in the form set
forth in Exhibit A hereto executed by the Pass Through Trustee by manual
signature, and such certificate of authentication upon any Certificate shall be
conclusive evidence, and the only evidence, that such Certificate has been duly
authenticated and delivered hereunder. All Certificates shall be dated the
date of their authentication.

SECTION 3.2. Authentication of Certificates. The Pass Through Trustee
shall duly authenticate and deliver Certificates in authorized denominations
equalling in the aggregate principal amount of the Equipment Notes and the
ETCs, as the case may be, to be purchased by the Pass Through Trustee pursuant
to the Equipment Trust Agreements, this Pass Through Trust Agreement and the
Participation Agreement, and evidencing the entire ownership of the Trust.

SECTION 3.3. Temporary Certificates. Pending the preparation of
Registered Certificates, the Pass Through Trustee may execute, authenticate and
deliver temporary Certificates which are printed, lithographed, typewritten, or
otherwise produced, in any denomination, containing substantially the same
terms and provisions as set forth in Exhibit A, except for such appropriate
insertions, omissions, substitutions and other variations relating to their
temporary nature as the officer executing such temporary Certificates may
determine, as evidenced by their execution of such temporary Certificates.

The Company will cause Registered Certificates to be prepared without
unreasonable delay after such Registered Certificates are required to be issued
pursuant to Section 3.9(d). After the preparation of Registered Certificates,
the temporary Certificates shall be exchangeable for Registered Certificates
upon surrender of the temporary Certificates at the Corporate Trust Office of
the Pass Through Trustee, or at the office or agency of the Pass Through
Trustee maintained in accordance with Section 7.12, without charge to the
holder. Upon surrender for cancellation of any one or more temporary
Certificates, the Pass Through Trustee shall execute, authenticate and deliver
in exchange therefor Registered Certificates of authorized denominations of a
like aggregate Fractional Undivided Interest; shall destroy any such temporary
Certificate(s) theretofore delivered and exchanged; and shall certify, in
writing, to the Company such destruction. Until so exchanged, such temporary
Certificates shall in all respects be entitled to the same benefits under this
Pass Through Trust Agreement as Registered Certificates.

SECTION 3.4. Registration of Transfer and Exchange of Certificates.
The Pass Through Trustee shall cause to be kept at the Corporate Trust Office
or the office or agency to be maintained by it in accordance with the
provisions of Section 7.12 a register (the "Register") in which, subject to
such reasonable regulations as it may prescribe, the Pass Through Trustee shall
provide for the registration of Certificates and of transfers and exchanges of
Certificates as herein provided. The Pass Through Trustee shall initially be
the registrar (the "Registrar") for the purpose of registering Certificates and
transfers and exchanges of Certificates as herein provided.

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Upon surrender for registration of transfer of any Certificate at the
Corporate Trust Office or such other office or agency, the Pass Through Trustee
shall execute, authenticate and deliver, in the name of the designated
transferee or transferees, one or more new Certificates in authorized
denominations of a like aggregate Fractional Undivided Interest.

At the option of a Certificateholder, Certificates may be exchanged
for other Certificates of authorized denominations of a like aggregate
Fractional Undivided Interest, upon surrender of the Certificates to be
exchanged at any such office or agency. Whenever any Certificates are so
surrendered for exchange, the Pass Through Trustee shall execute, authenticate
and deliver the Certificates that the Certificateholder making the exchange is
entitled to receive. Every Certificate presented or surrendered for
registration of transfer or exchange shall be duly endorsed or accompanied by a
written instrument of transfer in form satisfactory to the Pass Through Trustee
and the Registrar duly executed by the Certificateholder thereof or its
attorney duly authorized in writing.

No service charge shall be made to a Certificateholder for any
registration of transfer or exchange of Certificates, but the Pass Through
Trustee shall require payment of a sum sufficient to cover any tax or
governmental charge that may be imposed in connection with any transfer or
exchange of Certificates.

All Certificates surrendered for registration of transfer and exchange
shall be canceled and subsequently destroyed by the Pass Through Trustee. The
Pass Through Trustee shall provide the Company with written certification as to
the destruction of all such Certificates.

SECTION 3.5. Mutilated, Destroyed, Lost or Stolen Certificates. If
(a) any mutilated Certificate is surrendered to the Registrar, or the Registrar
receives evidence to its satisfaction of the destruction, loss or theft of any
Certificate, and (b) there is delivered to the Registrar and the Pass Through
Trustee such security, indemnity or bond, as may be required by them to save
each of them harmless, then, in the absence of notice to the Registrar or the
Pass Through Trustee that such Certificate has been acquired by a bona fide
purchaser, the Pass Through Trustee shall execute, authenticate and deliver, in
exchange for or in lieu of any such mutilated, destroyed, lost or stolen
Certificate, a new Certificate of like Fractional Undivided Interest with the
same final Regular Distribution Date. In connection with the issuance of any
new Certificate under this Section 3.5, the Pass Through Trustee shall require
the payment of a sum sufficient to cover any tax or other governmental charge
that may be imposed in relation thereto and any other expenses (including the
fees and expenses of the Pass Through Trustee and the Registrar) connected
therewith. Any duplicate Certificate issued pursuant to this Section 3.5 shall
constitute conclusive evidence of the appropriate Fractional Undivided Interest
in the Pass Through Trust, as if originally issued, whether or not the lost,
stolen or destroyed Certificate shall be found at any time.

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SECTION 3.6. Persons Deemed Owners. Prior to due presentation of a
Certificate for registration of transfer, the Pass Through Trustee, the
Registrar, and any Paying Agent of the Pass Through Trustee may treat the
person in whose name any Certificate is registered as the owner of such
Certificate for the purpose of receiving distributions pursuant to Section 4.2
and for all other purposes whatsoever, and neither the Pass Through Trustee,
the Registrar, nor any Paying Agent of the Pass Through Trustee shall be
affected by any notice to the contrary.

SECTION 3.7. Cancellation. All Certificates surrendered for payment
or transfer or exchange shall, if surrendered to any Person party hereto other
than the Registrar, be delivered to the Registrar for cancellation. No
Certificates shall be authenticated in lieu of or in exchange for any
Certificates canceled as provided in this Section, except as expressly
permitted by this Pass Through Trust Agreement. All canceled Certificates held
by the Registrar shall be destroyed and a certification of their destruction
delivered to the Pass Through Trustee and the Company.

SECTION 3.8. Limitation of Liability for Payments. All payments or
distributions made to Certificateholders under this Pass Through Trust
Agreement shall be made only from the Trust Property and only to the extent
that the Pass Through Trustee shall have sufficient income or proceeds from the
Trust Property to make such payments in accordance with the terms of Article IV
of this Pass Through Trust Agreement. Each Certificateholder, by its
acceptance of a Certificate, agrees that it will look solely to the income and
proceeds from the Trust Property to the extent available for distribution to
the Certificateholder thereof as provided in this Pass Through Trust Agreement.

SECTION 3.9. Book-Entry and Registered Certificates.

(a) Except for the De Minimis Certificate (if any), the Certificates
may be issued in the form of one or more typewritten Certificates representing
the Book-Entry Certificates, to be delivered to The Depository Trust Company,
the initial Clearing Agency, by, or on behalf of, the Certificate Owners. In
such case, the Certificates delivered to The Depository Trust Company shall
initially be registered on the Register in the name of Cede & Co., the nominee
of the initial Clearing Agency, and no Certificate Owner will receive a
Registered Certificate representing such Certificate Owner's interest in the
Certificates, except as provided above and in Subsection (d) below. Except
with respect to the De Minimis Certificate (if any), unless and until
Registered Certificates have been issued pursuant to Subsection (d) below:

(i) the provisions of this Section 3.9 shall be in full force
and effect;

(ii) the Company, the Paying Agent, the Registrar and the
Pass Through Trustee may deal with the Clearing Agency for all
purposes (including the making of distributions on the Certificates)
as the authorized representative of the Certificate Owners;

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(iii) to the extent that the provisions of this Section 3.9
conflict with any other provisions of this Pass Through Trust
Agreement, the provisions of this Section 3.9 shall control;

(iv) the rights of Certificate Owners shall be exercised only
through the Clearing Agency and shall be limited to those established
by law and agreements between such Certificate Owners and the Clearing
Agency Participants; and until Registered Certificates are issued
pursuant to Subsection (d) below, the Clearing Agency will make
book-entry transfers among the Clearing Agency Participants and
receive and transmit distributions of principal and interest and
Make-Whole Amount, if any, on the Certificates to such Clearing Agency
Participants; and

(v) whenever this Pass Through Trust Agreement requires or
permits actions to be taken based upon instructions or directions of
Certificateholders holding Certificates evidencing a specified
percentage of the Fractional Undivided Interests, the Clearing Agency
shall be deemed to represent such percentage only to the extent that
it has received instructions to such effect from Certificate Owners
and/or Clearing Agency Participants owning or representing,
respectively, such required percentage of the beneficial interest in
Certificates and has delivered such instructions to the Pass
Through Trustee. The Pass Through Trustee shall have no obligation to
determine whether the Clearing Agency has in fact received any such
instructions.

(b) Except with respect to the De Minimis Certificate (if any),
whenever notice or other communication to the Certificateholders is required
under this Pass Through Trust Agreement, unless and until Registered
Certificates shall have been issued pursuant to Subsection (d) below, the Pass
Through Trustee shall give all such notices and communications specified herein
to be given to Certificateholders to the Clearing Agency and/or the Clearing
Agency Participants, and shall make available additional copies as requested by
such Clearing Agency Participants.

(c) Unless and until Registered Certificates are issued pursuant to
Subsection (d) below, on the Record Date prior to each Regular Distribution
Date and Special Distribution Date, the Pass Through Trustee will request from
the Clearing Agency a Securities Position Listing setting forth the names of
all Clearing Agency Participants reflected on the Clearing Agency's books as
holding interests in the Certificates on such Record Date. The Pass Through
Trustee will mail to each such Clearing Agency Participant the statements
described in Section 4.3 hereof.

(d) If (i) Union, on behalf of the Company, advises the Pass Through
Trustee in writing that the Clearing Agency is no longer willing or able to
properly discharge its responsibilities and the Pass Through Trustee or Union,
on behalf of the Company is unable to locate a qualified successor, (ii) Union,
on behalf of the Company, at its option, advises the Pass Through Trustee in
writing that it elects to terminate the book-entry system through the Clearing
Agency or (iii) after the occurrence of an Event of Default, Certificate Owners
of Book-Entry Certificates

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evidencing Fractional Undivided Interests aggregating not less than a majority
in interest in the Pass Through Trust, by act of such Certificate Owners
delivered to the Company, and the Pass Through Trustee, advise the Pass Through
Trustee and the Clearing Agency through the Clearing Agency Participants in
writing that the continuation of a book-entry system through the Clearing
Agency is no longer in the best interests of the Certificate Owners, then the
Pass Through Trustee shall notify all Certificate Owners, through the Clearing
Agency, of the occurrence of any such event and of the availability of
Registered Certificates. Upon surrender to the Pass Through Trustee of all the
Certificates held by the Clearing Agency, accompanied by registration
instructions from the Clearing Agency for registration of Registered
Certificates in the names of Certificate Owners, the Pass Through Trustee shall
issue and deliver the Registered Certificates in accordance with the
instructions of the Clearing Agency. Upon the issuance of Registered
Certificates pursuant to this Section 3.9(d), the Record Date with respect to
such Registered Certificates shall be the fifth Business Day preceding a
Regular Distribution Date or Special Distribution Date, as applicable. Neither
the Company, the Registrar, the Paying Agent nor the Pass Through Trustee shall
be liable for any delay in delivery of such instructions and may conclusively
rely on, and shall be protected in relying on, such registration instructions.
Upon the issuance of Registered Certificates, the Pass Through Trustee shall
recognize the Persons in whose name the Registered Certificates are registered
as the Certificateholders hereunder. Neither the Company nor the Pass Through
Trustee shall be liable if the Pass Through Trustee or Union, on behalf of the
Company is unable to locate a qualified successor Clearing Agency.

(e) The Pass Through Trustee shall enter into the Letter of
Representations and fulfill its responsibilities thereunder.

ARTICLE IV

DISTRIBUTIONS; STATEMENTS TO
CERTIFICATEHOLDERS

SECTION 4.1. Certificate Account and Special Payments Account.

(a) The Pass Through Trustee shall establish and maintain on behalf
of the Certificateholders the Certificate Account as one or more accounts,
which shall be non-interest bearing accounts. The Pass Through Trustee shall
hold the Certificate Account in trust for the benefit of the
Certificateholders, and shall make or permit withdrawals therefrom only as
provided in this Pass Through Trust Agreement. On each day when a Scheduled
Payment is made under the Indenture or an Equipment Trust Agreement to the Pass
Through Trustee, as holder of either the Equipment Notes or the ETCs issued
under the Indenture or such Equipment Trust Agreement, as the case may be, the
Pass Through Trustee upon receipt shall immediately deposit the aggregate
amount of such Scheduled Payment in the Certificate Account.

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(b) The Pass Through Trustee shall establish and maintain on behalf
of the Certificateholders the Special Payments Account as one or more accounts,
which shall be non-interest bearing except as provided in Section 4.4. The
Pass Through Trustee shall hold the Special Payments Account in trust for the
benefit of the Certificateholders, and shall make or permit withdrawals
therefrom only as provided in this Pass Through Trust Agreement. On each day
when one or more Special Payments (other than a Special Payment that represents
the proceeds of any sale pursuant to Article VI by the Pass Through Trustee of
an Equipment Note) are made under an Equipment Trust Agreement or the Indenture
to the Pass Through Trustee, as holder of either the Equipment Notes or the
ETCs issued under the Indenture or such Equipment Trust Agreement, as the case
may be, the Pass Through Trustee upon receipt shall immediately deposit the
aggregate amounts of such Special Payments in the Special Payments Account. On
the day Union makes the payment to the Pass Through Trustee described in the
fifth paragraph of Section 2.1(b), the Pass Through Trustee upon receipt shall
immediately deposit the aggregate amount thereof in the Certificate Account.
Upon the sale of any Equipment Note or ETC by the Pass Through Trustee pursuant
to Article VI and the realization of any proceeds thereof, the Pass Through
Trustee shall deposit the aggregate amount of such proceeds as a Special
Payment in the Special Payments Account.

(c) The Pass Through Trustee shall present to the Indenture Trustee
to which an Equipment Note relates such Equipment Note on the date of its
stated final maturity, or in the case of any Equipment Note which is to be
prepaid in whole pursuant to the relevant Indenture, on the applicable
prepayment date under the Indenture.

(d) The Pass Through Trustee shall present to the Equipment Trust
Trustee to which an ETC relates such ETC on the date of its stated final
maturity.

SECTION 4.2. Distribution from Certificate Account and Special Payments
Account.

(a) On each Regular Distribution Date or as soon thereafter as the
Pass Through Trustee has confirmed receipt of the payment of the Scheduled
Payments due with respect to the Equipment Notes or ETCs on such date, the Pass
Through Trustee shall distribute to the Certificateholders of the Pass Through
Trust out of the Certificate Account the entire amount deposited therein
pursuant to Section 4.1(a). There shall be so distributed to each
Certificateholder of record on the Record Date with respect to such Regular
Distribution Date (other than as provided in Section 11.1 concerning the final
distribution) by check mailed to such Certificateholder at the address
appearing in the Register, such Certificateholder's pro rata share (based on
the aggregate Fractional Undivided Interest held by such Certificateholder) of
the aggregate amount in the Certificate Account; provided, however, that prior
to the time that any Certificates are issued in the form of Registered
Certificates, each Certificateholder may request in writing that such amounts
be distributed by wire transfer of immediately available funds to an account
specified by such Certificateholder. If a Scheduled Payment is not received by
the Pass Through Trustee on a Regular Distribution Date but is received on a
later date, it shall be

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distributed on the date received in the manner described in the preceding
sentence to the Certificateholders of record on the Record Date with respect to
such Regular Distribution Date.

(b) On each Special Distribution Date with respect to any Special
Payment or as soon thereafter as the Pass Through Trustee has confirmed receipt
of the Special Payments due on the Equipment Notes or ETCs or realized upon the
sale of any Equipment Note or ETCs, the Pass Through Trustee shall distribute
out of the Special Payments Account the entire amount deposited therein
pursuant to Section 4.1(b) of such Special Payment. There shall be so
distributed to each Certificateholder of record on the Record Date with respect
to such Special Distribution Date (other than as provided in Section 11.1
concerning the final distribution) by check mailed to such Certificateholder at
the address appearing in the Register, such Certificateholder's pro rata share
(based on the aggregate Fractional Undivided Interest held by such
Certificateholder) of the aggregate amount in the Special Payments Account on
account of such Special Payment; provided, however, that prior to the time that
any Certificates are issued in the form of Registered Certificates, each
Certificateholder may request in writing that such amount be distributed by
wire transfer of immediately available funds to an account specified by such
Certificateholder.

(c) The Pass Through Trustee shall at the expense of the Company
cause notice of each Special Payment to be mailed to each Certificateholder at
his address as it appears in the Register. In the case of a Special Payment
other than pursuant to the fifth paragraph of Section 2.1(b) or the fifth
paragraph of Section 2.1(c), such notice shall be mailed not less than 15 days
prior to the date any such Special Payment is scheduled to be distributed. In
the case of a Special Payment pursuant to the fifth paragraph of Section 2.1(b)
or the fifth paragraph of Section 2.1(c) such notice should be given as
promptly as practicable after the receipt of notice from the Company that
Postponed Notes or the Equipment Notes or Union ETCs referred to in Section
2.1(c) will not be issued. In the case of any other Special Payments, such
notice shall be mailed as soon as practicable after the Pass Through Trustee
has confirmed that it has received funds for such Special Payment. Notices
mailed by the Pass Through Trustee shall set forth:

(i) the Special Distribution Date and the Record Date
therefor (except as otherwise provided in Section 11.1),

(ii) the amount of the Special Payment for each $1,000 face
amount Certificate (taking into account any payment to be made by the
Company pursuant to
Section 2.1(b) or (c), as applicable) and the
amount thereof constituting principal, Make-Whole Amount, if any, and
interest,

(iii) the reason for the Special Payment, and

(iv) if the Special Distribution Date is the same date as a
Regular Distribution Date, the total amount to be received on such
date for each $1,000 face amount Certificate.

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If the amount of Make-Whole Amount, if any, payable upon the
prepayment of an Equipment Note has not been calculated at the time that the
Pass Through Trustee mails notice of a Special Payment, it shall be sufficient
if the notice sets forth the other amounts to be distributed and states that
any Make-Whole Amount received will also be distributed.

If any prepayment of the Equipment Notes is canceled, the Pass Through
Trustee, as soon as possible after learning thereof, shall cause notice thereof
to be mailed to each Certificateholder at its address as it appears on the
Register.

SECTION 4.3. Statements to Certificateholders.

(a) On each Regular Distribution Date and Special Distribution Date,
the Pass Through Trustee will include with each distribution of a Scheduled
Payment or a Special Payment to Certificateholders a statement, giving effect
to such distribution to be made on such Regular Distribution Date or Special
Distribution Date, as the case may be, setting forth the following information
(for each $1,000 face amount Certificate as to (i) and (ii) below):

(i) The amount of such distribution allocable to principal
and the amount allocable to Make-Whole Amount, if any;

(ii) The amount of such distribution allocable to interest; and

(iii) The Pool Balance and the Pool Factor.

(b) Within a reasonable period of time after the end of each calendar
year but not later than the latest date permitted by law, the Pass Through
Trustee shall furnish to each Person who at any time during such calendar year
was a Certificateholder of record a statement containing the sum of the amounts
determined pursuant to clauses (a)(i) and (a)(ii) of this Section 4.3 with
respect to the Pass Through Trust for such calendar year or, in the event such
Person was a Certificateholder of record during a portion of such calendar
year, for the applicable portion of such year, and such other items as are
readily available to the Pass Through Trustee and which a Certificateholder
shall reasonably request as necessary for the purpose of such
Certificateholder's preparation of its Federal income tax returns. Such report
and such other items shall be prepared on the basis of information supplied to
the Pass Through Trustee by the Clearing Agency Participants and shall be
delivered by the Pass Through Trustee to such Clearing Agency Participants to
be available for forwarding by such Clearing Agency Participants to Certificate
Owners.

SECTION 4.4. Investment of Special Payment Money. Any money received
by the Pass Through Trustee pursuant to Section 4.1(b) representing a Special
Payment which is not to be promptly distributed shall, to the extent
practicable, be invested in Permitted Investments by the Pass Through Trustee
pending distribution of such Special Payment pursuant to Section 4.2. Any

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investment made pursuant to this Section 4.4 shall be in such Permitted
Investments having maturities not later than the date that such moneys are
required to be used to make the payment required under Section 4.2 on the
applicable Special Distribution Date and the Pass Through Trustee shall hold
any such Permitted Investments until maturity. The Pass Through Trustee shall
have no liability with respect to any investment made pursuant to this Section
4.4, other than by reason of the willful misconduct or gross negligence of the
Pass Through Trustee. All income and earnings from such investments shall be
distributed to the Certificateholders on such Special Distribution Date as part
of such Special Payment.

ARTICLE V

THE COMPANY

SECTION 5.1. Maintenance of Corporate Existence. Each of the
Company, at its own cost and expense, will do or cause to be done all things
necessary to preserve and keep in full force and effect its corporate
existence, rights and franchises, except as otherwise specifically permitted in
Section 5.2; provided, however, that neither of the Company shall be required
to preserve any right or franchise if it shall determine that the preservation
thereof is no longer desirable in the conduct of its business.

SECTION 5.2. Consolidation, Merger or Sale of Assets Permitted.

(a) Union shall not consolidate with or merge into any other
corporation or sell or convey all or substantially all of its assets to any
Person, unless the corporation formed by such consolidation or into which Union
is merged or the Person which acquires by sale or conveyance all or
substantially all of the assets of Union, shall be a corporation organized and
existing under the laws of the United States of America or any State or the
District of Columbia, and shall execute and deliver to the Pass Through Trustee
an agreement in form reasonably satisfactory to the Pass Through Trustee
containing an assumption by such successor corporation of the due and punctual
performance and observance of each covenant and condition of this Agreement to
which Union is a party.

(b) Immediately after giving effect to such transaction, no Event of
Default, no Indenture Default, no Equipment Trust Default, and no event that,
after notice or lapse of time, or both, would become an Event of Default, an
Indenture Default or an Equipment Trust Default, shall have occurred and be
continuing.

Upon any consolidation or merger, or any sale or conveyance, of all or
substantially all of the assets of Union, the successor corporation formed by
such consolidation or into which Union, is merged or to which such sale or
conveyance is made shall succeed to, and be substituted for, and may exercise
every right and power of, Union, under this Agreement with the same effect

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as if such successor corporation had been named as Union, herein. No such sale
or conveyance of all or substantially all of the assets of Union, as an
entirety shall have the effect of releasing Union, or any successor corporation
which shall theretofore have become such from its liability hereunder.

(c) The Pass Through Trustee may accept an Officer's Certificate and
an Opinion of Counsel of Union, on behalf of the Company, as conclusive
evidence that any such consolidation, merger, sale, lease or conveyance, and
any such assumption complies with the provisions of this Section 5.2.

ARTICLE VI

DEFAULT

SECTION 6.1. Events of Default. If an Indenture Default under the
Indenture or an Equipment Trust Default under either Equipment Trust Agreement
(an "Event of Default") shall occur and be continuing, then, and in each and
every case, so long as such Event of Default shall be continuing, the Pass
Through Trustee may vote all of the Equipment Notes issued under the Indenture
or ETCs issued under either of the Equipment Trust Agreements, as the case may
be, to which such Event of Default relates that are held in the Trust Property,
and upon the direction of the Certificateholders holding Certificates
evidencing Fractional Undivided Interests aggregating not less than a majority
in interest in the Pass Through Trust, the Trustee shall vote a corresponding
majority of such Equipment Notes or such ETCs, as the case may be, in favor of
directing the Indenture Trustee under the Indenture or the Equipment Trust
Trustee under such Equipment Trust Agreement, as the case may be, to declare
the unpaid principal amount of all Equipment Notes then outstanding under the
Indenture or the ETCs then outstanding under such Equipment Trustee Agreement,
as the case may be, and accrued interest thereon to be due and payable under,
and in accordance with the provisions of, the Indenture or such Equipment Trust
Agreement, as the case may be. In addition, if an Indenture Default shall have
occurred and be continuing under the Indenture or an Equipment Trust Default
shall have occurred and be continuing under either Equipment Trust Agreement,
the Pass Through Trustee may, and upon the direction of the Certificateholders
holding Certificates evidencing Fractional Undivided Interests aggregating not
less than a majority in interest in the Pass Through Trust, shall, vote all of
the Equipment Notes issued under such Indenture or the ETCs issued under such
Equipment Trust Agreement, as the case may be, to which such Event of Default
relates that are held in the Pass Through Trust to direct such Indenture
Trustee or such Equipment Trust Trustee, as the case may be, regarding the
exercise of remedies provided in Article V of the Indenture or Article V of
such Equipment Trust Agreement, as the case may be.

In addition, after an Event of Default shall have occurred and be
continuing with respect to any Equipment Notes or ETCs, the Pass Through
Trustee may in its discretion, and upon the

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direction of the Certificateholders holding Certificates evidencing Fractional
Undivided Interests aggregating not less than a majority in interest in the
Pass Through Trust shall, by such officer or agent as it may appoint, sell,
convey, transfer and deliver (to the extent permitted by applicable law) all or
part of such Equipment Notes or ETCs, without recourse to or warranty by the
Pass Through Trustee or any Certificateholder, to any Person. In any such
case, the Pass Through Trustee shall sell, assign, contract to sell or
otherwise dispose of and deliver such Equipment Note or Equipment Notes or ETC
or ETCs in one or more parcels at public or private sale or sales, at any
location or locations at the option of the Pass Through Trustee, all upon such
terms and conditions as it may reasonably deem advisable and at such prices as
it may reasonably deem advisable, for cash. If the Pass Through Trustee so
decides or is required to sell or otherwise dispose of any Equipment Note or
ETC pursuant to this Section, the Pass Through Trustee shall take such of the
actions described above as it may reasonably deem most effectual to complete
the sale or other disposition of such Equipment Note or ETC, so as to provide
for the payment in full of all amounts due on the Certificates.

If, with respect to any Equipment Notes, an Indenture Default shall
have occurred and be continuing and the Owner Trustee, which is a party to the
Indenture has elected, in accordance with the provisions of Section 5.04(b) of
the Indenture, to purchase all of the then outstanding Equipment Notes issued
under the Indenture at a price equal to the aggregate unpaid principal amount
thereof, together with accrued interest thereon to the date of such purchase,
then the Pass Through Trustee shall sell to such Owner Trustee all of the
Equipment Notes issued under the Indenture held in the Pass Through Trust at a
price equal to the aggregate unpaid principal amount thereof, together with
accrued interest thereon to the date of such sale.

In no event shall (i) an Indenture Default constitute an Equipment
Trust Default or (ii) an Equipment Trust Default constitute an Indenture
Default.

SECTION 6.2. Incidents of Sale of Equipment Notes and ETCs. Upon any
sale of all or any part of the Equipment Notes or ETCs, as the case may be,
made either under the power of sale given under this Pass Through Trust
Agreement or otherwise for the enforcement of this Pass Through Trust
Agreement, the following shall be applicable:

(i) Certificateholders and Pass Through Trustee May Purchase
Equipment Notes or ETCs. Any Certificateholder, the Pass Through
Trustee in its individual or any other capacity or any other Person
may bid for and purchase any of the Equipment Notes or ETCs, as the
case may be, and upon compliance with the terms of sale, may hold,
retain, possess and dispose of such Equipment Notes or ETCs, as the
case may be, in their own absolute right without further
accountability; provided, however, that this provision shall not apply
to the sale of Equipment Notes or ETCs, as the case may be, pursuant
to the last paragraph of Section 6.1.

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(ii) Receipt of Pass Through Trustee Shall Discharge
Purchaser. The receipt of the Pass Through Trustee or of the officer
making such sale shall be a sufficient discharge to any purchaser for
his purchase money, and, after paying such purchase money and
receiving such receipt, such purchaser or its personal representative
or assigns shall not be obliged to see to the application of such
purchase money, or be in any way answerable for any loss,
misapplication or non-application thereof.

(iii) Application of Moneys Received Upon Sale. Any moneys
collected by the Pass Through Trustee upon any sale made either under
the power of sale given by this Pass Through Trust Agreement or
otherwise for the enforcement of this Pass Through Trust Agreement,
shall be applied as provided in Section 4.2(b).

SECTION 6.3. Judicial Proceedings Instituted by Pass Through Trustee.

(a) Pass Through Trustee May Bring Suit. If there shall be a failure
to make payment of the principal of, Make-Whole Amount, if any, or interest on
any Equipment Note or ETC, or if there shall be any failure to pay Rent (as
defined in the Lease) under the Lease when due and payable, then the Pass
Through Trustee, in its own name, and as trustee of an express trust, as holder
of such Equipment Notes or ETC, shall be, to the extent permitted by and in
accordance with the terms of the Note Documents or ETC Documents, entitled and
empowered to institute any suits, actions or proceedings at law, in equity or
otherwise, for the collection of the sums so due and unpaid on such Equipment
Notes or ETCs or under the Lease and may prosecute any such claim or proceeding
to judgment or final decree with respect to the whole amount of any such sums
so due and unpaid.

(b) Pass Through Trustee May File Proofs of Claim; Appointment of
Pass Through Trustee as Attorney-in-Fact in Judicial Proceedings. The Pass
Through Trustee in its own name, or as trustee of an express trust, or as
attorney-in-fact for the Certificateholders, or in any one or more of such
capacities (irrespective of whether distributions on the Certificates shall
then be due and payable, or the payment of the principal on the Equipment Notes
or ETCs, as the case may be, shall then be due and payable, as therein
expressed or by declaration or otherwise and irrespective of whether the Pass
Through Trustee shall have made any demand to the Indenture Trustee for the
payment of overdue principal, Make-Whole Amount (if any) or interest on
Equipment Notes or ETCs, as the case may be), shall be entitled and empowered
to file such proofs of claim and other papers or documents as may be necessary
or advisable in order to have the claims of the Pass Through Trustee and of the
Certificateholders allowed in any receivership, insolvency, bankruptcy,
liquidation, readjustment, reorganization or any other judicial proceedings
relative to the Company, the Owner Trustee, the Owner Participant, the
Equipment Trust Trustees or their respective creditors or property. Any
receiver, assignee, trustee, liquidator, sequestrator (or similar official) in
any judicial proceeding is hereby authorized by each Certificateholder to make
payments in respect of such claim to the Pass Through Trustee and, in the event
that the Pass Through Trustee shall consent to the making of such payments
directly to the

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37

Certificateholders, to pay to the Pass Through Trustee any amount due to it for
the reasonable compensation, expenses, disbursements and advances of the Pass
Through Trustee, its agents and counsel. Nothing contained in this Pass
Through Trust Agreement shall be deemed to give to the Pass Through Trustee any
right to accept or consent to any plan of reorganization or otherwise by action
of any character in any such proceeding to waive of change in any way any right
of any Certificateholder.

SECTION 6.4. Control by Certificateholders. Subject to Section 2.3,
the Certificateholders holding Certificates evidencing Fractional Undivided
Interests aggregating not less than a majority in interest in the Pass Through
Trust shall have the right to direct the time, method and place of conducting
any proceeding for any remedy available to the Pass Through Trustee, or
exercising any trust or power conferred on the Pass Through Trustee under this
Pass Through Trust Agreement, including any right of the Pass Through Trustee
as holder of the Equipment Notes or ETCs, provided that:

(i) such direction shall not be in conflict with any rule of
law or with this Pass Through Trust Agreement and would not involve
the Pass Through Trustee in personal liability or expense,

(ii) the Pass Through Trustee shall not determine that the
action so directed would be unjustly prejudicial to the
Certificateholders not taking part in such direction, it being
understood that (subject to Section 7.1) the Pass Through Trustee
shall have no duty to ascertain whether or not such actions or
forebearances are unjustly prejudicial to such certificateholders,

(iii) the Pass Through Trustee may take any other action
deemed proper by the Pass Through Trustee which is not inconsistent
with such direction, and

(iv) if an Indenture Default under the Indenture or an
Equipment Trust Default under either Equipment Trust Agreement shall
have occurred and be continuing, such direction shall not obligate the
Trustee to vote more than a corresponding majority of the related
Equipment Notes or ETCs, as the case may be, held by the Trust in
favor of directing any action by the Indenture Trustee with respect to
such Indenture Default or by the Equipment Trust Trustee with respect
to such Equipment Trust Default, as the case may be.

SECTION 6.5. Waiver of Past Defaults. The Certificateholders holding
Certificates evidencing Fractional Undivided Interests aggregating not less
than a majority in interest in the Pass Through Trust may on behalf of all of
the Certificateholders waive any past Event of Default hereunder and its
consequences or may instruct the Pass Through Trustee to waive any past default
under the Indenture, either Equipment Trust Agreement or this Agreement and its
consequences, except a default (i) in the payment of the principal of,
Make-Whole Amount, if

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any, or interest on any Equipment Notes or ETCs, as the case may be, or (ii) in
respect of a covenant or provision hereof which under Article IX hereof cannot
be modified or amended without the consent of the Certificateholder holding
each Outstanding Certificate affected.

Upon any such waiver, such default shall cease to exist with respect
to this Pass Through Trust Agreement, and any Event of Default arising
therefrom shall be deemed to have been cured for every purpose of this Pass
Through Trust Agreement and any direction given by the Pass Through Trustee on
behalf of such Certificateholders to the Indenture Trustee or Equipment Trust
Trustee, as the case may be, shall be annulled with respect thereto; but no
such waiver shall extend to any subsequent or other default or Event of Default
or impair any right consequent thereon. Upon any such waiver, the Pass Through
Trustee shall vote all the Equipment Notes issued under the Indenture or ETCs
issued under the relevant Equipment Trust Agreement, as the case may be, to
waive the corresponding Default.

SECTION 6.6. Undertaking to Pay Court Costs. All parties to this
Pass Through Trust Agreement, and each Certificateholder by his acceptance of a
Certificate, shall be deemed to have agreed that any court may in its
discretion require, in any suit, action or proceeding for the enforcement of
any right or remedy under this Pass Through Trust Agreement, or in any suit,
action or proceeding against the Pass Through Trustee for any action taken or
omitted by it as Pass Through Trustee hereunder, the filing by any party
litigant in such suit, action or proceeding of an undertaking to pay the costs
of such suit, action or proceeding, and that such court may, in its discretion,
assess reasonable costs, including reasonable attorney's fees, against any
party litigant in such suit, action or proceeding, having due regard to the
merits and good faith of the claims or defenses made by such party litigant;
provided, however, that the provisions of this Section shall not apply to (a)
any suit, action or proceeding instituted by any Certificateholder or group of
Certificateholders evidencing Fractional Undivided Interests aggregating more
than 10% of the Pass Through Trust, (b) any suit, action or proceeding
instituted by any Certificateholder for the enforcement of the distribution of
payments pursuant to Section 4.2 hereof on or after the respective due dates
expressed herein or (c) any suit, action or proceeding instituted by the Pass
Through Trustee or as to which the Pass Through Trustee is made a party.

SECTION 6.7. Right of Certificateholders to Receive Payments Not to
Be Impaired. Anything in this Pass Through Trust Agreement to the contrary
notwithstanding, including without limitation Section 6.8 hereof, the right of
any Certificateholder to receive distributions of payments required pursuant to
Section 4.2 hereof on the Certificates when due, or to institute suit for
the enforcement of any such payment on or after the applicable Regular
Distribution Date or Special Distribution Date, shall not be impaired or
affected without the consent of such Certificateholder.

SECTION 6.8. Certificateholders May Not Bring Suit Except Under
Certain Conditions. A Certificateholder shall not have the right to institute
any suit, action or proceeding at law or in equity or otherwise with respect to
this Pass Through Trust Agreement, for the appointment of

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a receiver or for the enforcement of any other remedy under this Pass Through
Trust Agreement, unless:

(i) such Certificateholder previously shall have given
written notice to the Pass Through Trustee of a continuing Event of
Default;

(ii) the Certificateholders holding Certificates evidencing
Fractional Undivided Interests aggregating not less than 25% of the
Pass Through Trust shall have requested the Pass Through Trustee in
writing to institute such action, suit or proceeding and shall have
offered to the Pass Through Trustee indemnity as provided in
Section 7.3(v);

(iii) the Pass Through Trustee shall have refused or
neglected to institute any such action, suit or proceeding for 60 days
after receipt of such notice, request and offer of indemnity; and

(iv) no direction inconsistent with such written request has
been given to the Pass Through Trustee during such 60-day period by
the Certificateholders holding Certificates evidencing Fractional
Undivided Interests aggregating not less than an a majority in
interest in the Pass Through Trust.

It is understood and intended that no one or more of the
Certificateholders shall have any right in any manner whatever hereunder or
under the Certificates to (x) surrender, impair, waive, affect, disturb or
prejudice any property in the Trust Property or the lien of the Indenture or
any Equipment Trust Agreement on any property subject thereto, or the rights of
the Certificateholders or the holders of the Equipment Notes or ETCs, as the
case may be, (y) obtain or seek to obtain priority over or preference to any
other such Certificateholder or (z) enforce any right under this Pass Through
Trust Agreement, except in the manner herein provided and for the equal,
ratable and common benefit of all the Certificateholders subject to the
provisions of this Pass Through Trust Agreement.

SECTION 6.9. Remedies Cumulative. Every remedy given hereunder to the
Pass Through Trustee or to any of the Certificateholders shall not be exclusive
of any other remedy or remedies, and every such remedy shall be cumulative and
in addition to every other remedy given hereunder or now or hereafter given by
statute, law, equity or otherwise.

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ARTICLE VII

THE PASS THROUGH TRUSTEE

SECTION 7.1. Certain Duties and Responsibilities.

(a) Except during the continuance of an Event of Default,

(i) the Pass Through Trustee undertakes to perform only such
duties as are specifically set forth in this Pass Through Trust
Agreement, and no implied covenants, duties or obligations shall be
read into this Pass Through Trust Agreement against the Pass Through
Trustee; and

(ii) in the absence of bad faith on its part, the Pass
Through Trustee may conclusively rely, as to the truth of the
statements and the correctness of the opinions expressed therein, upon
certificates or opinions furnished to the Pass Through Trustee and
conforming to the requirements of this Pass Through Trust Agreement;
but in the case of any such certificates or opinions which by
any provision hereof are specifically required to be furnished to the
Pass Through Trustee, the Pass Through Trustee shall be under a duty
to examine the form of the same to determine whether or not they
substantially conform to the requirements of this Pass Through Trust
Agreement, but shall be under no duty to investigate the facts
contained therein.

(b) In case an Event of Default has occurred and is continuing, the
Pass Through Trustee shall exercise such of the right and powers vested in it
by this Pass Through Trust Agreement, and use the same degree of care and skill
in its exercise, as a prudent man would exercise or use under the circumstances
in the conduct of his own affairs.

(c) No provision of this Pass Through Trust Agreement shall be
construed to relieve the Pass Through Trustee from liability for its own
negligent action, its own negligent failure to act, or its own willful
misconduct, except that

(i) this Subsection shall not be construed to limit the
effect of Subsection (a) of this Section;

(ii) the Pass Through Trustee shall not be liable for any
error of judgement made in good faith by a Responsible Officer of the
Pass Through Trustee;

(iii) the Pass Through Trustee shall not be liable with
respect to any action taken or omitted to be taken by it in good faith
in accordance with the direction of the Certificateholders evidencing
Fractional Undivided Interests aggregating not less than a majority in
interest in the Pass Through Trust relating to the time, method and
place of

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conducting any proceeding for any remedy available to the Pass Through Trustee,
or exercising any trust or power conferred upon the Pass Through Trustee, under
this Pass Through Trust Agreement; and

(iv) no provision of this Pass Through Trust Agreement shall
require the Pass Through Trustee to expend or risk its own funds in
the performance of any of its duties hereunder, or in the exercise of
any of its rights or powers, if it shall have reasonable grounds for
believing that payment of such funds or adequate indemnity against
such risk is not reasonably assured to it.

(d) Whether or not herein expressly so provided, every provision of
this Pass Through Trust Agreement relating to the conduct or affecting the
liability of or affording protection to the Pass Through Trustee shall be
subject to the provisions of this Section.

SECTION 7.2. Notice of Defaults. As promptly as practicable after,
and in any event within 30 days after, the occurrence of any default (as such
term is defined below) hereunder, the Pass Through Trustee shall transmit by
mail to the Certificateholders, the Company, the Owner Trustee, the Equipment
Trust Trustees and the Indenture Trustees in accordance with Section 313(c) of
the Trust Indenture Act, notice of such default hereunder known to the Pass
Through Trustee, unless such default shall have been cured or waived; provided,
however, that, except in the case of a default in the payment of the principal
of (or Make-Whole Amount, if any) or interest on any Equipment Note or ETC, as
the case may be, the Pass Through Trustee shall be protected in withholding
such notice if and so long as the board of directors, the executive committee
or a trust committee of directors and/or Responsible Officers of the Pass
Through Trustee in good faith determine that the withholding of such notice is
in the interests of the Certificateholders. For the purpose of this Section,
the term "default" means the occurrence of any Event of Default, except that in
determining whether any such Event of Default has occurred for the purposes of
this paragraph any grace period or notice in connection therewith shall be
disregarded.

SECTION 7.3. Certain Rights of Trustee. Except as otherwise provided
in Section 7.1:

(i) the Pass Through Trustee may rely and shall be protected
in acting or refraining from acting in reliance upon any resolution,
certificate, statement, instrument, opinion, report, notice, request,
direction, consent, order, bond, debenture or other paper or document
believed by it to be genuine and to have been signed or presented by
the proper party or parties;

(ii) any request or direction of the Company mentioned herein
shall be sufficiently evidenced by a Request;

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(iii) whenever in the administration of this Pass Through
Trust Agreement the Pass Through Trustee shall deem it desirable that
a matter be proved or established prior to taking, suffering or
omitting any action hereunder, the Pass Through Trustee (unless other
evidence be herein specifically prescribed) may, in the absence of bad
faith on its part, rely upon an Officer's Certificate of Union, on
behalf of the Company, the Owner Trustee, the Equipment Trust Trustee
or the Indenture Trustee;

(iv) Before the Pass Through Trustee acts or refrains from
acting;

(v) the Pass Through Trustee may consult with counsel and the
advice of such counsel or any Opinion of Counsel shall be full and
complete authorization and protection in respect of any action taken,
suffered or omitted by it hereunder in good faith and in reliance
thereon;

(vi) the Pass Through Trustee shall be under no obligation to
exercise any of the rights or powers vested in it by this Pass Through
Trust Agreement at the request or direction of any of the
Certificateholders pursuant to this Pass Through Trust Agreement,
unless such Certificateholders shall have offered to the Pass Through
Trustee reasonable security or indemnity against the cost, expenses
and liabilities which might be incurred by it in compliance with such
request or direction;

(vii) the Pass Through Trustee shall not be bound to make any
investigation into the facts or matters stated in any resolution,
certificate, statement, instrument, opinion, report, notice, request,
direction, consent, order, bond, debenture or other paper or document;

(viii) the Pass Through Trustee may execute any of the trusts
or powers hereunder or perform any duties hereunder either directly or
by or through agents or attorneys and the Pass Through Trustee shall
not be responsible for any misconduct or negligence on the part of any
agent or attorney appointed with due care by it hereunder;

(ix) to the extent the provisions of this Section 7.3 are
inconsistent with the duties of the Pass Through Trustee as required
by Section 315 of the Trust Indenture Act, the requirements of such
Section 315 shall prevail;

(x) The Pass Through Trustee shall not be required to give
any bond or surety in respect of the performance of its powers and
duties hereunder; and

(xi) the permissive rights of the Pass Through Trustee shall
not be construed as a duty.

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SECTION 7.4. Not Responsible for Recitals or Issuance of
Certificates. The recitals contained herein and in the Certificates, except
the certificates of authentication, shall not be taken as the statements of the
Pass Through Trustee, and the Pass Through Trustee assumes no responsibility
for their correctness. Subject to Section 7.15, the Pass Through Trustee makes
no representations as to the validity or sufficiency of this Pass Through
Trust Agreement, any Note Document, any ETC Document, the Participation
Agreement, the Equipment Notes, the ETCs or the Certificates, except that the
Pass Through Trustee hereby represents and warrants that this Pass Through
Trust Agreement has been, and each Certificate will be, executed and delivered
by one of its officers who is duly authorized to execute and deliver such
document on its behalf.

SECTION 7.5. May Hold Certificates. The Pass Through Trustee, any
Paying Agent, Registrar or any of their Affiliates or any other agent, in their
respective individual or any other capacity, may become the owner or pledgee of
Certificates and, subject to Sections 310(b) and 311 of the Trust Indenture
Act, may otherwise deal with the Company, the Owner Trustee, the Equipment
Trust Trustees or the Indenture Trustee with the same rights it would have if
it were not Pass Through Trustee, Paying Agent, Registrar or such other agent.

SECTION 7.6. Money Held in Pass Through Trust. Money held by the Pass
Through Trustee or the Paying Agent in trust hereunder need not be segregated
from other funds except to the extent required herein or by law and neither the
Pass Through Trustee nor the Paying Agent shall have any liability for interest
upon any such moneys except as provided for herein.

SECTION 7.7. Compensation and Reimbursement. The Company agree,
severally and jointly:

(i) to pay, or cause to be paid, pursuant to separate
agreements between the Company and the Pass Through Trustee to the
Pass Through Trustee from time to time reasonable compensation for all
services rendered by it hereunder (which compensation shall not be
limited by any provision of law in regard to the compensation of a
trustee of an express trust), except for the Pass Through Trustee's
initial fees, which fees shall be paid by the Owner Trustee;

(ii) except as otherwise expressly provided herein, to
reimburse, or cause to be reimbursed, the Pass Through Trustee upon
its request for all reasonable out-of-pocket expenses, disbursements
and advances incurred or made by the Pass Through Trustee in
accordance with any provision of this Pass Through Trust Agreement
(including the reasonable compensation and the expenses and
disbursements of its agents and counsel), except any such expense,
disbursement or advance as may be attributable to its negligence, or
willful misconduct or as may be incurred due to the Pass Through
Trustee's breach of its representations and warranties set forth in
Sections 7.4 and 7.15 and except for the initial reasonable actual
disbursements made by the Pass Through Trustee, which disbursements
shall be reimbursed by the Owner Trustee;

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(iii) to indemnify, or cause to be indemnified, the Pass
Through Trustee, in its individual and trust capacities, for, and to
hold it harmless against, any loss, liability or expense (other than
for or with respect to any tax) incurred without negligence or willful
misconduct on its part, arising out of or in connection with the
acceptance or administration of this Pass Through Trust, including the
costs and expenses of defending itself against or investigating any
claim or liability in connection with the exercise or performance of
any of its powers or duties hereunder, except for any such loss,
liability or expense incurred by reason of the Pass Through Trustee's
breach of its representations and warranties set forth in Sections 7.4
and 7.15. The Pass Through Trustee shall notify the Company promptly
of any claim for which it may seek indemnity. The Company shall
defend the claim and the Pass Through Trustee shall cooperate in the
defense. The Pass Through Trustee may have separate counsel with the
consent of the Company, and the Company will pay the reasonable fees
and expenses of such counsel. The Company need not pay for any
settlement made without their consent; and

(iv) to indemnify, or cause to be indemnified, the Pass
Through Trustee, solely in its individual capacity, for, and to hold
it harmless against, any tax (other than for or with respect to any
tax referred to in the next paragraph, provided that no
indemnification shall be available with respect to any tax
attributable to the Pass Through Trustee's compensation for serving as
such) incurred without negligence or willful misconduct on its part,
arising out of or in connection with the acceptance or administration
of this Pass Through Trust, including any costs and expenses
reasonably incurred in contesting the imposition of any such tax. The
Pass Through Trustee, in its individual capacity, shall notify the
Company promptly of any tax for which it may seek indemnity. The
Company shall defend against the imposition of such tax and the Pass
Through Trustee, in its individual capacity, shall cooperate in the
defense. The Pass Through Trustee, in its individual capacity, may
have separate counsel with the consent of the Company, and the Company
will pay the reasonable fees and expenses of such counsel. The
Company need not pay for any taxes paid, in settlement or otherwise,
without their consent.

In addition, the Pass Through Trustee shall be entitled to
reimbursement from, and shall have a lien prior to the Certificates upon, all
property and funds held or collected by the Pass Through Trustee in its
capacity as Pass Through Trustee for any tax incurred without negligence or
willful misconduct, on its part, arising out of or in connection with the
acceptance or administration of this Pass Through Trust (other than any tax
attributable to the Pass Through Trustee's compensation for serving as such),
including any costs and expenses reasonably incurred in contesting the
imposition of any such tax. If the Pass Through Trustee reimburses itself for
any such tax, it will within 30 days mail a brief report setting forth the
circumstances thereof to all Certificateholders as their names and addresses
appear in the Register.

The Pass Through Trustee shall have a lien prior to the Certificates
upon all property and funds held or collected by the Pass Through Trustee in
its capacity as Pass Through Trustee.

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If the Pass Through Trustee incurs expenses or renders services after
an Event of Default specified in Section 6.1 occurs, such expenses and the
compensation for such services are intended to constitute expenses of
administration under any Bankruptcy Law.

SECTION 7.8. Corporate Trustee Required; Eligibility. This Agreement
shall at all times have a Pass Through Trustee which shall be eligible to act
as a trustee under Section 310(a) of the Trust Indenture Act and shall have a
combined capital and surplus of at least $100,000,000 and the obligations of
which, whether now in existence or hereafter incurred, are fully and
unconditionally guaranteed by a corporation organized and doing business under
the laws of the United States of America, any State or Territory thereof or of
the District of Columbia and having a combined capital and surplus of at least
$100,000,000. If such corporation publishes reports of condition at least
annually, pursuant to law or the requirements of Federal, State, Territorial or
District of Columbia supervising or examining authority, then for the purposes
of this Section 7.8, the combined capital and surplus of such corporation shall
be deemed to be its combined capital and surplus as set forth in its most
recent report of condition so published.

The Pass Through Trustee shall comply with Section 310(b) of the Trust
Indenture Act.

In case at any time the Pass Through Trustee shall cease to be
eligible in accordance with the provisions of this Section 7.8, the Pass
Through Trustee shall resign immediately in the manner and with the effect
specified in Section 7.9.

SECTION 7.9. Resignation and Removal; Appointment of Successor.

(a) No resignation or removal of the Pass Through Trustee and no
appointment of a successor Pass Through Trustee pursuant to this Article shall
become effective until the acceptance of appointment by the successor Pass
Through Trustee under Section 7.10.

(b) The Pass Through Trustee may resign at any time by giving written
notice thereof to the Company, the Authorized Agents, the Owner Trustees, the
Equipment Trust Trustees and the Indenture Trustee. If an instrument of
acceptance by a successor Pass Through Trustee shall not have been delivered to
the Company, the Owner Trustee, the Equipment Trust Trustees and the Indenture
Trustee within 30 days after the giving of such notice of resignation, the
resigning Pass Through Trustee may petition any court of competent jurisdiction
for the appointment of a successor Pass Through Trustee.

(c) The Pass Through Trustee may be removed at any time by Act of the
Certificateholders holding Certificates evidencing Fractional Undivided
Interests aggregating not less than a majority in interest in the Pass Through
Trust delivered to the Pass Through Trustee and to the Company, the Owner
Trustee, the Equipment Trustee Trustees and the Indenture Trustee.

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(d) If at any time:

(i) the Pass Through Trustee shall fail to comply with
Section 310 of the Trust Indenture Act after written request therefor
by the Company or by any Certificateholder who has been a bona fide
Certificateholder for at least six months; or

(ii) the Pass Through Trustee shall cease to be eligible
under Section 7.8 and shall fail to resign after written request
therefor by the Company or by any such Certificateholder; or

(iii) the Pass Through Trustee shall become incapable of
acting or shall be adjudged a bankrupt or insolvent or a receiver of
the Pass Through Trustee or of its property shall be appointed or any
public officer shall take charge or control of the Pass Through
Trustee or of its property or affairs for the purpose of
rehabilitation, conservation or liquidation;

then, in any case, (x) the Company may remove the Pass Through Trustee or (y)
subject to Section 6.6, any Certificateholder who has been a bona fide
Certificateholder for at least six months may, on behalf of himself and all
others similarly situated, petition any court of competent jurisdiction for the
removal of the Pass Through Trustee and the appointment of a successor Pass
Through Trustee.

(e) If a Responsible Officer of the Pass Through Trustee shall obtain
actual knowledge of an Avoidable Tax (as hereinafter defined) which has been or
is likely to be asserted, the Pass Through Trustee shall promptly notify the
Company and the Owner Trustee thereof and shall, within 30 days of such
notification, resign hereunder unless within such 30-day period the Pass
Through Trustee shall have received notice that the Company or the Owner
Trustees have agreed to pay such tax. The Company shall promptly appoint a
successor Pass Through Trustee in a jurisdiction where there are no Avoidable
Taxes. As used herein, an "Avoidable Tax" means a state or local tax: (i) upon
(w) the Pass Through Trust, (x) the Trust Property, (y) Certificateholders or
(z) the Pass Through Trustee for which the Pass Through Trustee is entitled to
seek reimbursement from the Trust Property, and (ii) which would be avoided if
the Pass Through Trustee were located in another state, or jurisdiction within
a state, within the United States. A tax shall not be an Avoidable Tax if the
Company or the Owner Trustee shall agree to pay, and shall pay, such tax.

(f) If the Pass Through Trustee shall resign, be removed or become
incapable of acting, or if a vacancy shall occur in the office of the Pass
Through Trustee for any cause, Union shall promptly appoint a successor Pass
Through Trustee. If, within one year after such resignation, removal or
incapacity, or the occurrence of such vacancy, a successor Pass Through Trustee
shall be appointed by Act of the Certificateholders holding Certificates
evidencing Fractional Undivided Interests aggregating not less than a majority
in interest in the Pass Through Trust delivered to

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the Company, the Owner Trustee, the Indenture Trustee, the Equipment Trust
Trustees and the retiring Pass Through Trustee, the successor Pass Through
Trustee so appointed shall, forthwith upon its acceptance of such appointment,
become the successor Pass Through Trustee and supersede the retiring Pass
Through Trustee. If no successor Pass Through Trustee shall have been so
appointed as provided above and accepted appointment in the manner hereinafter
provided, any Certificateholder who has been a bona fide Certificateholder for
at least six months may, on behalf of himself and all others similarly
situated, petition any court of competent jurisdiction for the appointment of a
successor Pass Through Trustee.

(g) The successor Pass Through Trustee shall give notice of the
resignation and removal of the Pass Through Trustee and appointment of the
successor Pass Through Trustee by mailing written notice of such event by
first-class mail, postage prepaid, to the Certificateholders as their names and
addresses appear in the Register. Each notice shall include the name of such
successor Pass Through Trustee and the address of its Corporate Trust Office.

SECTION 7.10. Acceptance of Appointment by Successor. Every
successor Pass Through Trustee appointed hereunder shall execute, acknowledge
and deliver to the Company and the retiring Pass Through Trustee an instrument
accepting such appointment, and thereupon the resignation or removal of the
retiring Pass Through Trustee shall become effective and such successor Pass
Through Trustee, without any further act, deed or conveyance, shall become
vested with all the rights, powers, trusts and duties of the retiring Pass
Through Trustee; but, on request of the Company or the successor Pass Through
Trustee, such retiring Pass Through Trustee shall execute and deliver an
instrument transferring to such successor Pass Through Trustee all the rights,
powers and trusts of the retiring Pass Through Trustee and shall duly assign,
transfer and deliver to such successor Pass Through Trustee all property and
money held by such retiring Pass Through Trustee hereunder, subject
nevertheless to its lien, if any, provided for in Section 7.7. Upon request of
any such successor Pass Through Trustee, Union, the retiring Pass Through
Trustee and such successor Pass Through Trustee shall execute and deliver any
and all instruments containing such provisions as shall be necessary or
desirable to transfer and confirm to, and for more fully and certainly vesting
in, such successor Pass Through Trustee all such rights, powers and trusts.

No successor Pass Through Trustee shall accept its appointment unless
at the time of such acceptance such successor Pass Through Trustee shall be
qualified and eligible under this Article.

SECTION 7.11. Merger, Conversion, Consolidation or Succession to
Business. Any corporation into which the Pass Through Trustee may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which the Pass Through Trustee
shall be a party, or any corporation succeeding to all or substantially all of
the corporate trust business of the Pass Through Trustee, shall be the
successor of the Pass Through Trustee hereunder, provided such corporation
shall be otherwise qualified and eligible under this Article, without the
execution or filing of any paper or any further act on

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the part of any of the parties hereto. In case any Certificates shall have
been authenticated, but not delivered, by the Pass Through Trustee then in
office, any successor by merger, conversion or consolidation to such
authenticating Pass Through Trustee may adopt such authentication and deliver
the Certificates so authenticated with the same effect as if such successor
Pass Through Trustee had itself authenticated such Certificates.

SECTION 7.12. Maintenance of Agencies.

(a) There shall at all times be maintained in the Borough of
Manhattan, The City of New York, an office or agency where Certificates may be
presented or surrendered for registration of transfer or for exchange, and for
payment thereof and where notices and demands to or upon the Pass Through
Trustee in respect of the Certificates or of this Pass Through Trust Agreement
may be served. Such office or agency shall be initially at Xxxxxx Trust and
Savings Bank, Xxxxxx Trust Company of New York, 00 Xxxxx Xxxxxx, 0xx Xxxxx, Xxx
Xxxx, Xxx Xxxx 00000. Written notice of the location of each such other
office or agency and of any change of location thereof shall be given by the
Pass Through Trustee to Union, the Owner Trustee, the Indenture Trustee, the
Equipment Trust Trustees and the Certificateholders. In the event that no such
office or agency shall be maintained or no such notice of location or of change
of location shall be given, presentations and demands may be made and notices
may be served at the Corporate Trust Office of the Pass Through Trustee.

(b) There shall at all times be a Registrar and a Paying Agent
hereunder. Each such Authorized Agent shall be a bank or trust company, shall
be a corporation organized and doing business under the laws of the United
States of America or any State or Territory thereof or of the District of
Columbia, with a combined capital and surplus of at least $75,000,000, or, if
the Pass Through Trustee shall be acting as the Registrar or Paying Agent
hereunder, a corporation the obligations of which are guaranteed by a
corporation organized and doing business under the laws of the United States of
America or any State or Territory thereof or of the District of Columbia, with
a combined capital and surplus of at least $75,000,000, and shall be authorized
under such laws to exercise corporate trust powers, subject to supervision by
Federal or state authorities. The Pass Through Trustee shall initially be the
Paying Agent and, as provided in Section 3.4, Registrar hereunder. Each
Registrar shall furnish to the Pass Through Trustee, at stated intervals of not
more than six months, and at such other times as the Pass Through Trustee may
request in writing, a copy of the Register.

(c) Any corporation into which any Authorized Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, consolidation or conversion to which any Authorized Agent
shall be a party, or any corporation succeeding to the corporate trust business
of any Authorized Agent, shall be the successor of such Authorized Agent
hereunder, if such successor corporation is otherwise eligible under this
Section, without the execution or filing of any paper or any further act on the
part of the parties hereto or such Authorized Agent or such successor
corporation.

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(d) Any Authorized Agent may at any time resign by giving written
notice of resignation to the Pass Through Trustee, the Company, the Owner
Trustee, the Equipment Trust Trustees and the Indenture Trustee. The Company
may, and at the request of the Pass Through Trustee shall, at any time
terminate the agency of any Authorized Agent by giving written notice of
termination to such Authorized Agent and to the Pass Through Trustee. Upon the
resignation or termination of an Authorized Agent or in case at any time any
such Authorized Agent shall cease to be eligible under this Section (when, in
either case, no other Authorized Agent performing the functions of such
Authorized Agent shall have been appointed), the Company shall promptly appoint
one or more qualified successor Authorized Agents, reasonably satisfactory to
the Pass Through Trustee, to perform the functions of the Authorized Agent
which has resigned or whose agency has been terminated or who shall have ceased
to be eligible under this Section. Union shall give written notice of any such
appointment made by them to the Pass Through Trustee, the Owner Trustee, the
Equipment Trust Trustees and the Indenture Trustee; and in each case the Pass
Through Trustee shall mail notice of such appointment to all Certificateholders
as their names and addresses appear on the Register.

(e) The Company agree, severally and not jointly, to pay, or cause to
be paid, pursuant to separate agreements from time to time to each Authorized
Agent reasonable compensation for its services and to reimburse it for its
reasonable expenses.

SECTION 7.13. Money for Certificate Payments to Be Held in Pass
Through Trust. All moneys deposited with any Paying Agent for the purpose of
any payment on Certificates shall be deposited and held in trust for the
benefit of the Certificateholders entitled to such payment, subject to the
provisions of this Section. Moneys so deposited and held in trust shall
constitute a separate trust fund for the benefit of the Certificateholders with
respect to which such money was deposited.

The Pass Through Trustee will cause each Paying Agent other than the
Pass Through Trustee to execute and deliver to it an instrument in which such
Paying Agent shall agree with the Pass Through Trustee, subject to the
provisions of this Section, that such Paying Agent will:

(i) hold all sums held by it for payments on Certificates in
trust for the benefit of the Persons entitled thereto until such sums
shall be paid to such Persons or otherwise disposed of as herein
provided;

(ii) give the Pass Through Trustee notice of any default by
any obligor upon the Certificates in the making of any such payment;
and

(iii) at any time during the continuance of any such default,
upon the written request of the Pass Through Trustee, forthwith pay to
the Pass Through Trustee all sums so held in trust by such Paying
Agent.

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The Pass Through Trustee may at any time, for the purpose of
obtaining the satisfaction and discharge of this Pass Through Trust Agreement
or for any other purpose, direct any Paying Agent to pay to the Pass Through
Trustee all sums held in trust by such Paying Agent, such sums to be held by
the Pass Through Trustee upon the same trusts as those upon which such sums
were held by such Paying Agent; and, upon such payment by any Paying Agent to
the Pass Through Trustee, such Paying Agent shall be released from all further
liability with respect to such money.

SECTION 7.14. Registration of Equipment Notes and ETCs in Pass
Through Trustee's Name. The Pass Through Trustee agrees that all Equipment
Notes, ETCs, Permitted Investments, if any, and Specified Investments, if any,
shall be issued in the name of the Pass Through Trustee or its nominee and held
by the Pass Through Trustee, or, if not so held, the Pass Through Trustee or
its nominee shall be reflected as the owner of such Equipment Notes, ETCs,
Permitted Investments, or Specified Investments, as the case may be, in the
register of the issuer of such Equipment Notes, ETCs, Permitted Investments or
Specified Investments. In no event shall the Pass Through Trustee invest in,
or hold, Equipment Notes, ETCs, Permitted Investments or Specified Investments
in a manner that would cause the Pass Through Trustee not to have the ownership
interest in such Equipment Notes, ETCs, Permitted Investments or Specified
Investments under the applicable provisions of the Uniform Commercial Code in
effect where the Pass Through Trustee holds such Equipment Notes, ETCs,
Permitted Investments or Specified Investments or other applicable law then in
effect.

SECTION 7.15. Representations and Warranties of Pass Through Trustee.
The Pass Through Trustee hereby represents and warrants that:

(i) the Pass Through Trustee is an Illinois banking
corporation validly existing and holding a valid certificate to
conduct business as an Illinois banking corporation with trust powers
under the laws of the State of Illinois;

(ii) the Pass Through Trustee has full power, authority and
legal right to execute, deliver, and perform this Pass Through Trust
Agreement and the Participation Agreement and has taken all necessary
action to authorize the execution, delivery, and performance by it of
this Pass Through Trust Agreement and the Participation Agreement;

(iii) the execution, delivery and performance by the Pass
Through Trustee of this Pass Through Trust Agreement and the
Participation Agreement (a) will not violate any provision of any
United States or Illinois law or regulation governing the banking and
trust powers of the Pass Through Trustee or any order, writ, judgment,
or decree of any court, arbitrator, or governmental authority
applicable to the Pass Through Trustee or any of its assets, (b) will
not violate any provision of the articles of association or by- laws
of the Pass Through Trustee, or (c) will not violate any provision of,
or constitute, with or without notice or lapse of time, a default
under, or result in the creation or imposition of any lien on any
properties included in the Trust Property pursuant to the provisions
of any

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mortgage, indenture, contract, agreement or other undertaking to which
it is a party, which violation, default or lien could reasonably be
expected to have an adverse effect on the Pass Through Trustee's
performance or ability to perform its duties hereunder or thereunder or
on the transactions contemplated herein or therein;

(iv) the execution, delivery and performance by the Pass
Through Trustee of this Pass Through Trust Agreement and the
Participation Agreement will not require the authorization, consent,
or approval of, the giving of notice to, the filing or registration
with, or the taking of any other action in respect of, any United
States or Illinois governmental authority or agency regulating the
banking and corporate trust activities of the Pass Through Trustee,
other than any such authorization, consent or approval as has been
duly obtained or given and is in full force and effect; and

(v) this Pass Through Trust Agreement and the Participation
Agreement have been duly executed and delivered by the Pass Through
Trustee and constitute the legal, valid, and binding agreements of the
Pass Through Trustee, enforceable against it in accordance with their
respective terms, provided that enforceability may be limited by (x)
applicable bankruptcy, insolvency, reorganization, moratorium or
similar laws affecting the rights of creditors generally and (y)
general principles of equity.

SECTION 7.16. Withholding Taxes; Information Reporting. The Pass
Through Trustee, as trustee of a grantor trust, shall exclude and withhold from
each distribution of principal, Make-Whole Amount, if any, and interest and
other amounts due hereunder or under the Certificates any and all withholding
taxes applicable thereto as required by law. The Pass Through Trustee agrees
to act as such withholding agent and, in connection therewith, whenever any
present or future taxes or similar charges are required to be withheld with
respect to any amounts payable in respect of the Certificates, to withhold such
amounts and timely pay the same to the appropriate authority in the name of and
on behalf of the Certificateholders, that it will file any necessary
withholding tax returns or statements when due, and that, as promptly as
possible after the payment thereof, it will deliver to each Certificateholder
appropriate documentation showing the payment thereof, together with such
additional documentary evidence as such Certificateholders may reasonably
request from time to time. The Pass Through Trustee agrees to file any other
information reports as it may be required to file under United States law. To
the extent that the Pass Through Trustee fails, with respect to any
Certificateholder, to withhold and pay over any such taxes to the appropriate
taxing authority, the Pass Through Trustee shall, upon a claim being made for
such taxes by such authority, and before making any claim to Union for
indemnification under Section 7.1 of the Participation Agreement (if such
indemnification would otherwise be permissible thereunder), take all reasonable
steps to recover such taxes from such Certificateholder, including, without
limitation, withholding the amount of such taxes from subsequent distributions,
if any, to such Certificateholder. To the extent that the Pass Through Trustee
receives any amount from Union for indemnification of such taxes which the Pass
Through Trustee thereafter recovers from the appropriate Certificateholder
(including by

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withholding from subsequent distributions to such Certificateholder), the Pass
Through Trustee shall reimburse Union therefor. The Pass Through Trustee shall
be permitted to rely upon any certificate presented by a Certificateholder
claiming an exemption from withholding absent negligence or willful misconduct
on the part of the Pass Through Trustee.

SECTION 7.17. Trustee's Liens. The Pass Through Trustee in its
individual capacity agrees that it will at its own cost and expense promptly
take such actions as may be necessary to duly discharge and satisfy in full all
Trustee's Liens.

SECTION 7.18. Preferential Collection of Claims. The Pass Through
Trustee shall comply with Sections 311(a) and (b) of the Trust Indenture Act,
excluding any creditor relationship arising under Section 311(b) of the Trust
Indenture Act. A Pass Through Trustee who has resigned or been removed shall
be subject to Section 311(a) of the Trust Indenture Act to the extent
indicated.

ARTICLE VIII

CERTIFICATEHOLDERS' LISTS AND REPORTS BY PASS THROUGH TRUSTEE

SECTION 8.1. The Company to Furnish Pass Through Trustee with Names
and Addresses of Certificateholders. The Company will furnish to the Pass
Through Trustee within 15 days after each Record Date with respect to a
Scheduled Payment, and at such other times as the Pass Through Trustee may
request in writing, within 30 days after receipt by the Company of any such
request, a list, in such form as the Pass Through Trustee may reasonably
require, of all information in the possession or control of the Company as to
the names and addresses of the Certificateholders, in each case as of a date
not more than 15 days prior to the time such list is furnished; provided,
however, that so long as the Pass Through Trustee is the sole Registrar, no
such list need be furnished; and provided further, however, that no such list
need be furnished for so long as a copy of the Register is being furnished to
the Pass Through Trustee pursuant to Section 7.12.

SECTION 8.2. Preservation of Information; Communications to
Certificateholders. The Pass Through Trustee shall preserve, in as current a
form as is reasonably practicable, the names and addresses of
Certificateholders contained in the most recent Register or list furnished to
the Pass Through Trustee as provided in Section 7.12 or Section 8.1, as the
case may be, and the names and addresses of Certificateholders received by the
Pass Through Trustee in its capacity as Registrar, if so acting. The Pass
Through Trustee may destroy any Register or list furnished to it as provided in
Section 7.12 or Section 8.1, as the case may be, upon receipt of a new Register
or list so furnished.

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SECTION 8.3. Reports by Pass Through Trustee.

(a) Within 60 days after May 15 of each year commencing with the year
1997, the Pass Through Trustee shall transmit to the Certificateholders, as
provided in Section 313(c) of the Trust Indenture Act, a report dated as of
such May 15, if required by Section 313(a) of the Trust Indenture Act. The
Pass Through Trustee shall also comply with Section 313(b) of the Trust
Indenture Act.

(b) A copy of each such report shall, at the time of transmission to
Certificateholders, be filed by the Pass Through Trustee with each stock
exchange (if any) upon which the Certificates are listed, and also with the
Commission. The Company will notify the Pass Through Trustee when the
Certificates are listed on any stock exchange and any subsequent change with
respect thereto.

SECTION 8.4. Reports by the Company. Union shall:

(a) file with the Pass Through Trustee, within 30 days after it is
required to file the same with the Commission, copies of the annual reports and
of the information, documents and other reports (or copies of such portions of
any of the foregoing as the Commission may from time to time by rules and
regulations prescribe) which it is required to file with the Commission
pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934,
as amended; or if it is not required to file information, documents or reports
pursuant to either of such sections, then to file with the Pass Through Trustee
and the Commission, in accordance with rules and regulations prescribed by the
Commission pursuant to Section 314(a)(1) of the Trust Indenture Act, such of
the supplementary and periodic information, documents and reports which may be
required pursuant to Section 13 of the Securities Exchange Act of 1934, as
amended, in respect of a security listed and registered on a national
securities exchange as may be prescribed in such rules and regulations;

(b) file with the Pass Through Trustee and the Commission, in
accordance with the rules and regulations prescribed by the Commission, such
additional information, documents and reports with respect to compliance by it
with the conditions and covenants provided for in this Agreement, as may be
required by such rules and regulations, including, in the case of annual
reports, if required by such rules and regulations, certificates or opinions of
independent public accountants, conforming to the requirements of Section 1.2;

(c) transmit to all Certificateholders, in the manner and to the
extent provided in Section 313(c) of the Trust Indenture Act such summaries of
any information, documents and reports required to be filed by Union pursuant
to subsections (a) and (b) of this Section 8.4 as may be required by rules and
regulations prescribed by the Commission; and

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(d) furnish to the Pass Through Trustee, not less often than
annually, a certificate from the principal executive officer, principal
financial officer or principal accounting officer thereof as to his or her
knowledge of Union's compliance with all conditions and covenants under this
Agreement. For purposes of this subsection (d), such compliance shall be
determined without regard to any period of grace or requirement of notice
provided under this Agreement.

ARTICLE IX

SUPPLEMENTS TO PASS THROUGH TRUST AGREEMENT

SECTION 9.1. Supplements to Pass Through Trust Agreement Without
Consent of Certificateholders. Without the consent of the Certificateholders,
the Company may, and the Pass Through Trustee (subject to Section 9.3) shall,
at any time and from time to time enter into one or more agreements
supplemental hereto, in form satisfactory to the Pass Through Trustee, for any
of the following purposes:

(i) to evidence the succession of another corporation to
Union and the assumption by any such successor of the covenants of
Union herein contained;

(ii) to add to the covenants of either of the Company for the
benefit of the Certificateholders, or to surrender any right or power
herein conferred upon the Company;

(iii) to cure any ambiguity, to correct any manifest error to
correct or supplement any provision herein which may be defective or
inconsistent with any other provision herein or to make any other
provisions with respect to matters or questions arising under this
Pass Through Trust Agreement, provided that any such action shall not
adversely affect the interests of the Certificateholders; or

(iv) to modify, eliminate or add to the provisions of this
Pass Through Trust Agreement to such extent as shall be necessary to
continue the qualification of this Pass Through Trust Agreement
(including any supplemental agreement) under the Trust Indenture Act,
or under any similar Federal statute hereafter enacted, and to add to
this Pass Through Trust Agreement such other provisions as may be
expressly permitted by the Trust Indenture Act, excluding, however,
the provisions referred to in Section 316(a)(2) of the Trust Indenture
Act as in effect at the date as of which this instrument was executed
or any corresponding provision in any similar Federal statute
hereafter enacted.

SECTION 9.2. Supplements to Pass Through Trust Agreement with Consent
of Certificateholders. With the consent of the Certificateholders holding
Certificates evidencing Fractional Undivided Interests aggregating not less
than a majority in interest, by Act of such

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Certificateholders delivered to the Company and the Pass Through Trustee, the
Company may (with the consent of the Owner Trustee, if any, such consent not to
be unreasonably withheld), and the Pass Through Trustee (subject to Section
9.3) shall, enter into an agreement or agreements supplemental hereto for the
purpose of adding any provisions to or changing in any manner or eliminating
any of the provisions of this Pass Through Trust Agreement or of modifying in
any manner the rights and obligations of the Certificateholders under this Pass
Through Trust Agreement; provided, however, that no such supplemental agreement
shall, without the consent of each Certificateholder of an Outstanding
Certificate affected thereby:

(i) reduce in any manner the amount of, or delay the timing
of, any receipt by the Pass Through Trustee of payments on the
Equipment Notes or the ETCs held in the Pass Through Trust or
distributions that are required to be made herein on any Certificate,
or change any date of payment on any Certificate, or change the place
of payment where, or the coin or currency in which, any Certificate is
payable, or impair the right to institute suit for the enforcement of
any such payment or distribution on or after the Regular Distribution
Date or Special Distribution Date applicable thereto;

(ii) permit the disposition of any Equipment Note or ETCs in
the Trust Property except as permitted by this Pass Through Trust
Agreement, or otherwise deprive any Certificateholder of the
beneficial ownership of the Equipment Notes or ETCs in the Pass
Through Trust;

(iii) reduce the percentage of the aggregate Fractional
Undivided Interests of the Pass Through Trust required for any such
supplemental agreement, or reduce such percentage required for any
waiver (of compliance with certain provisions of this Pass Through
Trust Agreement or certain defaults hereunder and their consequences)
provided or in this Pass Through Trust Agreement;

(iv) modify Article XII or otherwise release Union from its
obligations under the Guarantee; or

(v) modify any of the provisions of this Section or Section
6.5, except to increase any such percentage or to provide that certain
other provisions of this Pass Through Trust Agreement cannot be
modified or waived without the consent of the Certificateholder of
each Certificate affected thereby.

It shall not be necessary for any Act of Certificateholders under this
Section to approve the particular form of any proposed supplemental agreement,
but it shall be sufficient if such Act shall approve the substance thereof.

SECTION 9.3. Documents Affecting Immunity or Indemnity. If in the
opinion of the Pass Through Trustee any document required to be executed by it
pursuant to the terms of

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Section 9.1 or 9.2 affects any interest, right, duty, obligation, immunity or
indemnity in favor of the Pass Through Trustee under this Pass Through Trust
Agreement, the Pass Through Trustee may in its discretion decline to execute
such document.

SECTION 9.4. Execution of Supplements to Pass Through Trust
Agreements. In executing, or accepting the additional trusts created by, any
supplemental agreement permitted by this Article or the modifications thereby
of the trusts created by this Pass Through Trust Agreement, the Pass Through
Trustee shall be entitled to receive, and shall be fully protected in relying
upon, an Opinion of Counsel stating that the execution of such supplemental
agreement is authorized or permitted by this Pass Through Trust Agreement.

SECTION 9.5. Effect of Supplements to Pass Through Trust Agreement.
Upon the execution of any supplemental agreement under this Article, this Pass
Through Trust Agreement shall be modified in accordance therewith, and such
supplemental agreement shall form a part of this Pass Through Trust Agreement
for all purposes; and every Certificateholder of Certificates theretofore or
thereafter authenticated and delivered hereunder shall be bound thereby.

SECTION 9.6. Conformity with Trust Indenture Act. Every supplemental
agreement executed pursuant to this Article shall conform to the requirements
of the Trust Indenture Act as then in effect.

SECTION 9.7. Reference in Certificates to Supplements to Pass Through
Trust Agreements. Certificates authenticated and delivered after the execution
of any supplemental agreement pursuant to this Article may bear a notation in
form approved by the Pass Through Trustee as to any matter provided for in such
supplemental agreement, and, in such case, suitable notation may be made upon
Outstanding Certificates after proper presentation and demand.

ARTICLE X

AMENDMENTS TO INDENTURE, NOTE DOCUMENTS,
EQUIPMENT TRUST AGREEMENTS AND ETC DOCUMENTS

In the event that the Pass Through Trustee, as holder of any Equipment
Note or an ETC in trust for the benefit of the Certificateholders, receives a
request for a consent to any amendment, modification, waiver or supplement
under the Indenture, other Note Document, either Equipment Trust Agreement,
other ETC Document or the Participation Agreement, the Pass Through Trustee
shall forthwith send a notice of such proposed amendment modification, waiver
or supplement, to each Certificateholder registered on the Register as of such
date. The Pass Through Trustee shall request from the Certificateholders
Directions as to (a) whether or not to direct the Indenture Trustee or such
Equipment Trust Trustee, as the case may be, to take or refrain from taking any
action which a holder of such Equipment Note or ETC, as the case may

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be, has the option to direct, (b) whether or not to give or execute any
waivers, consents, amendments, modifications or supplements as a holder of such
Equipment Note or ETC, as the case may be, and (c) how to vote any Equipment
Note or ETC, as the case may be, if a vote has been called for with respect
thereto. Provided such a request for Certificateholder Direction shall have
been made, in directing any action or casting any vote or giving any consent as
the holder of any Equipment Note or ETC, as the case may be, the Pass Through
Trustee shall vote or consent with respect to such Equipment Note or ETC, as
the case may be, in the same proportion as the Certificates were actually voted
by Acts of Certificateholders delivered to the Pass Through Trustee prior to
two Business Days before the Pass Through Trustee directs such action or casts
such vote or gives such consent. Notwithstanding the foregoing, but subject to
Section 6.4, in the case that an Event of Default hereunder shall have occurred
and be continuing, the Pass Through Trustee may, in its own discretion and at
its own direction, consent and notify the Indenture Trustee or Equipment Trust
Trustee of such consent to any amendment, modification, waiver or supplement
under the Indenture, and other Note Document, any Equipment Trust Agreement,
any other ETC Document or the Participation Agreement.

ARTICLE XI

TERMINATION OF PASS THROUGH TRUST

The respective obligations and responsibilities of the Company and the
Pass Through Trustee created hereby and the Pass Through Trust created hereby
shall terminate upon the distribution to all Certificateholders and the Pass
Through Trustee of all amounts required to be distributed to them pursuant to
this Pass Through Trust Agreement and the disposition of all property held as
part of the Trust Property; provided, however, that in no event shall the trust
created hereby continue beyond the expiration of 21 years from the death of the
last survivor of the descendants of Xxxx X. Xxxxxxxxxxx, father of Xxxxxx
Xxxxxxxxxxx, former Vice President of the United States, living on the date of
this Pass Through Trust Agreement.

Notice of any termination, specifying the Regular Distribution Date
(or Special Distribution Date, as the case may be) upon which the
Certificateholders may surrender their Certificates to the Pass Through Trustee
for payment of the final distribution and cancellation, shall be mailed
promptly by the Pass Through Trustee to Certificateholders not earlier than the
60th day and not later than the 20th day next preceding such final
distribution, specifying (a) the Regular Distribution Date (or Special
Distribution Date, as the case may be) upon which the proposed final payment of
the Certificates will be made upon presentation and surrender of Certificates
at the office or agency of the Pass Through Trustee therein specified, (b) the
amount of any such proposed final payment, and (c) that the Record Date
otherwise applicable to such Regular Distribution Date (or Special Distribution
Date, as the case may be) is not applicable, payments being made only upon
presentation and surrender of the Certificates at the office or agency of the
Pass Through Trustee therein specified. The Pass Through Trustee shall give
such

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notice to the Registrar at the time such notice is given to Certificateholders.
Upon presentation and surrender of the Certificates, the Pass Through Trustee
shall cause to be distributed to Certificateholders amounts distributable on
such Regular Distribution Date (or Special Distribution Date, as the case may
be) pursuant to Section 4.2.

In the event that all of the Certificateholders shall not surrender
their Certificates for cancellation within six months after the date specified
in the above-mentioned written notice, the Pass Through Trustee shall give a
second written notice to the remaining Certificateholders to surrender their
Certificates for cancellation and receive the final distribution with respect
thereto. In the event that any money held by the Pass Through Trustee for the
payment of distributions on the Certificates shall remain unclaimed for two
years and 11 months after the final distribution date with respect thereto, the
Pass Through Trustee shall pay to the Indenture Trustee or each Equipment Trust
Trustee the appropriate amount of money relating to the Indenture Trustee or
such Equipment Trust Trustee and shall give written notice thereof to the Owner
Trustee and Union.

ARTICLE XII

MISCELLANEOUS PROVISIONS

SECTION 12.1. Limitation on Rights of Certificateholders. The death
or incapacity of any Certificateholder shall not operate to terminate this Pass
Through Trust Agreement or the Pass Through Trust, nor entitle such
Certificateholder's legal representatives or heirs to claim an accounting or to
take any action or commence any proceeding in any court for a partition or
winding up of the Pass Through Trust, nor otherwise affect the rights,
obligations and liabilities of the parties hereto or any of them.

SECTION 12.2. Certificates Nonassessable and Fully Paid.
Certificateholders shall not be personally liable for obligations of the Pass
Through Trust, the Fractional Undivided Interests represented by the
Certificates shall be nonassessable for any losses or expenses of the Pass
Through Trust or for any reason whatsoever, and Certificates upon
authentication thereof by the Pass Through Trustee pursuant to Section 3.2 are
and shall be deemed fully paid. No Certificateholder shall have any right
(except as expressly provided herein) to vote or in any manner otherwise
control the operation and management of the Trust Property, the Pass Through
Trust established hereunder, or the obligations of the parties hereto, nor
shall anything set forth herein, or contained in the terms of the Certificates,
be construed so as to constitute the Certificateholders from time to time as
partners or members of an association.

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SECTION 12.3. Notices.

(a) Unless otherwise expressly specified or permitted by the terms
hereof, all communications and notices provided for herein shall be in writing,
and any such notice shall become effective (i) upon personal delivery thereof,
including, without limitation by overnight mail and courier service, (ii) in
the case of notice by United States mail, certified or registered, postage
prepaid, return receipt requested, three days after being so deposited in the
United States mail, or (iii) in the case of notice by facsimile transmission,
upon transmission thereof, provided such transmission is promptly confirmed
(which conformation may be mechanical), in each case addressed to each party
here to at the addresses set forth below:

if to Union, to:

Union Tank Car Company
000 Xxxx Xxxxxxxxxx Xxxxxx
Xxxxxxx, Xxxxxxxx 00000
Attention: Xxxxxx X. Xxxx, Secretary
Facsimile: (000) 000-0000
Telephone: (000) 000-0000

if to the Pass Through Trustee, to:

Xxxxxx Trust and Savings Bank
000 Xxxx Xxxxxx Xxxxxx
Xxxxxxx, Xxxxxxxx 00000
Attention: Indenture Trust Division\Xxx Xxxxxxx
Facsimile: (000) 000-0000
Telephone: (000) 000-0000

(b) The Company and the Pass Through Trustee, by notice to the other
parties, may designate additional or different addresses for subsequent notices
or communications.

(c) Any notice or communication to Certificateholders shall be mailed
by first-class mail to the addresses for Certificateholders shown on the
Register kept by the Registrar and to addresses filed with the Pass Through
Trustee for Certificate Owners. Failure so to mail a notice or communication
or any defect in such notice or communication shall not affect its sufficiency
with respect to other Certificateholders.

(d) If a notice or communication is mailed in the manner provided
above within the time prescribed, it is conclusively presumed to have been duly
given, whether or not the addressee receives it.

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(e) If the Company mail a notice or communication to the
Certificateholders, it shall mail a copy to the Pass Through Trustee and to
each Paying Agent at the same time.

(f) Notwithstanding the foregoing, all communications or notices to
the Pass Through Trustee shall be deemed to be given only when received by a
Responsible Officer of the Pass Through Trustee.

(g) The Pass Through Trustee shall promptly furnish the Company with
a copy of any demand, notice or written communication received by the Pass
Through Trustee hereunder from any Certificateholder, the Owner Trustee, any
Equipment Trust Trustee or the Indenture Trustee.

SECTION 12.4. Communication by Certificateholder with Other
Certificateholders. Certificateholders may communicate pursuant to Section
312(b) of the Trust Indenture Act with other Certificateholders with respect to
their rights under this Pass Through Trust Agreement or under the Certificates,
and the Pass Through Trustee shall comply with Section 312(b) of the Trust
Indenture Act. The Company and the Pass Through Trustee shall have the
protection of Section 312(c) of the Trust Indenture Act.

SECTION 12.5. Governing Law. THIS PASS THROUGH TRUST AGREEMENT SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW
YORK WITHOUT GIVING EFFECT TO ANY CHOICE OF LAW OF CONFLICT OF LAW PROVISION OR
RULE AND THE OBLIGATIONS, RIGHTS, AND REMEDIES OF THE PARTIES HEREUNDER SHALL
BE DETERMINED IN ACCORDANCE WITH SUCH LAWS.

SECTION 12.6. Severability of Provisions. Whenever possible, each
provision of this Pass Through Trust Agreement shall be interpreted in such
manner as to be effective and valid under applicable law, but if any provision
of this Pass Through Trust Agreement shall be prohibited by or invalid under
applicable law, such provision shall be ineffective to the extent of such
prohibition or invalidity, without invalidating the remainder of such provision
or the remaining provisions of this Pass Through Trust Agreement.

SECTION 12.7. Trust Indenture Act Controls. This Agreement is
subject to the provisions of the Trust Indenture Act and shall, to the extent
applicable, be governed by such provisions.

SECTION 12.8. Effect of Headings and Table of Contents. The Article
and Section headings herein and the Table of Contents are for convenience only
and shall not affect the construction hereof.

SECTION 12.9. Successors and Assigns. All covenants, agreements,
representations and warranties in this Pass Through Trust Agreement by the Pass
Through Trustee, the Company shall

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bind and, to the extent permitted hereby, shall inure to the benefit of and be
enforceable by their respective successors and assigns, whether so expressed or
not.

SECTION 12.10. Benefits of Pass Through Trust Agreement. Nothing in
this Pass Through Trust Agreement or in the Certificates, express or implied,
shall give to any Person, other than the parties hereto and their successors
hereunder, and the Certificateholders, any benefit or any legal or equitable
right, remedy or claim under this Pass Through Trust Agreement.

SECTION 12.11. Legal Holidays. In any case where any Regular
Distribution Date or Special Distribution Date relating to any Certificate
shall not be a Business Day, then (notwithstanding any other provision of this
Pass Through Trust Agreement) payment need not be made on such date, but may be
made on the next succeeding Business Day with the same force and effect as if
made on such Regular Distribution Date or Special Distribution Date, and no
interest shall accrue during the intervening period.

SECTION 12.12. Counterparts. For the purpose of facilitating the
execution of this Pass Through Trust Agreement and for other purposes, this
Pass Through Trust Agreement may be executed simultaneously in any number of
counterparts, each of which counterparts shall be deemed to be an original, and
all of which counterparts shall constitute but one and the same instrument.

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IN WITNESS WHEREOF, Union and the Pass Through Trustee have caused
this Pass Through Trust Agreement to be duly executed by their respective
officers, duly attested, all on the day and year first above written.

UNION TANK CAR COMPANY

Attest: By ______________________________
Title:

_________________________
Title:

XXXXXX TRUST AND SAVINGS BANK,
as Pass Through Trustee

Attest: By ______________________________
Title:

_________________________
Title:

-57-
63

EXHIBIT A

FORM OF CERTIFICATE

Unless this certificate is presented by an authorized representative
of The Depository Trust Company, a New York corporation ("DTC"), to issuers or
their agent for registration of transfer, exchange or payment, and any
Certificate issued is registered in the name of Cede & Co. or in such other
name as is requested by an authorized representative of DTC (and any payment is
made to Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch the registered owner hereof,
Cede & Co., has an interest herein.

UNION TANK CAR COMPANY

_______ PASS THROUGH TRUST

Pass Through Certificate,
Series _______

Final Distribution Date: ________________

evidencing a fractional undivided interest in a trust, the
property of which includes certain equipment notes (the "Equipment
Notes") and Equipment Trust Certificates ("ETCs") each secured by
equipment leased to Union Tank Car Company.

Certificate
No. ___ $ __________ Fractional Undivided Interest
representing 100% of the Trust

THIS CERTIFIES THAT Cede & Co., for value received, is the
registered owner of a $___________ (___________________________________________
____________________________________________________________________ dollars)
Fractional Undivided Interest in the Union Tank Car Company ______ Pass Through
Trust (the "Trust") created by _______________, a national banking association,
as trustee (the "Pass Through Trustee"), pursuant to a Pass Through Trust
Agreement ______ dated _______ (the "Pass Through Trust Agreement") among the
Pass Through Trustee, Union Tank Car Company, a Delaware corporation ("Union"),
a summary of certain of the pertinent provisions of which is set forth below.
To the extent not otherwise defined herein, the capitalized terms used herein
have the meanings assigned to them in the Pass Through Trust Agreement. This
Certificate is one of the

duly authorized Certificates designated as "Pass Through Certificates, Series
______" (herein called the "Certificates"). This Certificate is issued under
and is subject to the terms, provisions, and conditions of the Pass Through
Trust Agreement, to which Pass Through Trust Agreement the Certificateholder of
this Certificate by virtue of the acceptance hereof assents and by which such
Certificateholder is bound. The property of the Pass Through Trust (the "Trust
Property") includes certain Equipment Notes and ETCs. Each issue of Equipment
Notes and ETCs is secured by, among other things, a security interest in
Equipment leased to Union or conditionally sold to Procor, as the case may be.

Subject to and in accordance with the terms of the Pass
Through Trust Agreement, from funds then available to the Pass Through Trustee,
there will be distributed on _______ and ______ of each year (each a "Regular
Distribution Date"), commencing on _________, to the Person in whose name this
Certificate is registered at the close of business on the Business Day
preceding the Regular Distribution Date, an amount in respect of the Scheduled
Payments on the Equipment Notes and the ETCs due on such Regular Distribution
Date, the receipt of which has been confirmed by the Pass Through Trustee,
equal to the product of the percentage interest in the Pass Through Trust
evidenced by this Certificate and an amount equal to the sum of such Scheduled
Payments. Subject to and in accordance with the terms of the Pass Through
Trust Agreement, in the event that Special Payments on the Equipment Notes or
the ETCs are received by the Pass Through Trustee, from funds then available to
the Pass Through Trustee, there shall be distributed on the applicable Special
Distribution Date, to the Person in whose name this Certificate is registered
at the close of business on the Business Day preceding the Special Distribution
Date, an amount in respect of such Special Payments on the Equipment Notes or
the ETCs, the receipt of which has been confirmed by the Pass Through Trustee,
equal to the product of the percentage interest in the Pass Through Trust
evidenced by this Certificate and an amount equal to the sum of such Special
Payments so received. If a Regular Distribution Date or Special Distribution
Date is not a Business Day, distribution shall be made on the immediately
following Business Day with the same force and effect as if made on such
Regular Distribution Date or Special Distribution Date and no interest shall
accrue during the intervening period. The Special Distribution Date shall be
the second day of the month, or such other date, if any, determined as provided
in the Pass Through Trust Agreement. The Pass Through Trustee shall mail
notice of each Special Payment and the Special Distribution Date therefor to
the Certificateholder of this Certificate.

Distributions on this Certificate will be made by the Pass Through
Trustee by wire transfer of funds to the Person entitled thereto, without the
presentation or surrender of this Certificate or the making of any notation
hereon, provided, however, that in the event Certificates are issued in the
form of Registered Certificates, distributions on this Certificate will be made
by check mailed to the Person entitled thereto. Except as otherwise provided
in the Pass Through Trust Agreement and notwithstanding the above, the final
distribution on this Certificate will be made after notice mailed by the Pass
Through Trustee of the pendency of such distribution and only

A-2

upon presentation and surrender of this Certificate at the office or agency of
the Pass Through Trustee specified in such notice.

THIS CERTIFICATE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.

Reference is hereby made to the further provisions of this Certificate
set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

Unless the certificate of authentication hereon has been executed by
the Pass Through Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Pass Through Trust Agreement or be valid for
any purpose.

IN WITNESS WHEREOF, the Pass Through Trustee has caused this
Certificate to be duly executed.

UNION TANK CAR COMPANY
_______ PASS THROUGH TRUST

By: ___________________,
as Pass Through Trustee

By: ________________________________________
Title:

A-3
66

[Reverse of Certificate]

The Certificates do not represent a direct obligation of, or an
obligation guaranteed by (except to the extent provided in the Pass Through
Trust Agreement), or an interest in Union, the Pass Through Trustee, in its
individual or trust capacities, any Owner Participant, any Owner Trustee in its
individual capacity, either Equipment Trust Trustee in its individual capacity,
or any affiliate of any thereof. The Certificates are limited in right of
payment, all as more specifically set forth on the face hereof and in the Pass
Through Trust Agreement. All payments or distributions made to
Certificateholders under the Pass Through Trust Agreement shall be made only
from the Trust Property and only to the extent that the Pass Through Trustee
shall have sufficient income or proceeds from the Trust Property to make such
payments in accordance with the terms of the Pass Through Trust Agreement.
Each Certificateholder of this Certificate, by its acceptance hereof, agrees
that it will look solely to the income and proceeds from the Trust Property to
the extent available for distribution to such Certificateholder as provided in
the Pass Through Trust Agreement. This Certificate does not purport to
summarize the Pass Through Trust Agreement and reference is made to the Pass
Through Trust Agreement for information with respect to the interests, rights,
benefits, obligations, proceeds, and duties evidenced hereby. A copy of the
Pass Through Trust Agreement may be examined during normal business hours at
the principal office of the Pass Through Trustee, and at such other places, if
any, designated by the Pass Through Trustee, by any Certificateholder upon
request.

The Pass Through Trust Agreement permits, with certain exceptions
therein provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Certificateholders under the
Pass Through Trust Agreement at any time by the Company and the Pass Through
Trustee with the consent of the Certificateholders holding Certificates
evidencing Fractional Undivided Interests aggregating not less than a majority
in interest in the Pass Through Trust. Any such consent by the
Certificateholder of this Certificate shall be conclusive and binding on such
Certificateholder and upon all future Certificateholders of this Certificate
and of any Certificate issued upon the transfer hereof or in exchange hereof or
in lieu hereof whether or not notation of such consent is made upon this
Certificate. The Pass Through Trust Agreement also permits the amendment
thereof, in certain limited circumstances, without the consent of the
Certificateholders of any of the Certificates.

As provided in the Pass Through Trust Agreement and subject to certain
limitations therein set forth, the transfer of this Certificate is registrable
in the Register upon surrender of this Certificate for registration of transfer
at the offices or agencies maintained by the Pass Through Trustee in its
capacity as Registrar, or by any successor Registrar, in the Borough of
Manhattan, the City of New York, duly endorsed or accompanied by a written
instrument of transfer in form satisfactory to the Pass Through Trustee and the
Registrar duly executed by the Certificateholder hereof or such
Certificateholder's attorney duly authorized in writing, and thereupon one or
more

A-4
67

new Certificates of authorized denominations evidencing the same aggregate
Fractional Undivided Interest in the Pass Through Trust will be issued to the
designated transferee or transferees.

The Certificates are issuable only as registered Certificates without
coupons in minimum denominations of $1,000 and $1,000 integral multiples
thereof, except that one Certificate may be in a denomination of less than
$1,000. As provided in the Pass Through Trust Agreement and subject to certain
limitations therein set forth, Certificates are exchangeable for new
Certificates of authorized denominations evidencing the same aggregate
Fractional Undivided Interest in the Pass Through Trust, as requested by the
Certificateholder surrendering the same.

No service charge will be made for any such registration of transfer
or exchange, but the Pass Through Trustee shall require payment of a sum
sufficient to cover any tax or governmental charge payable in connection
therewith.

The Pass Through Trustee, the Registrar, and any agent of the Pass
Through Trustee or the Registrar may treat the person in whose name this
Certificate is registered as the owner hereof for all purposes, and neither the
Pass Through Trustee, the Registrar, nor any such agent shall be affected by
any notice to the contrary.

The obligations and responsibilities created by the Pass Through Trust
Agreement and the Pass Through Trust created thereby shall terminate upon the
distribution to Certificateholders of all amounts required to be distributed to
them pursuant to the Pass Through Trust Agreement and the disposition of all
property held as part of the Trust Property.

A-5
68

[FORM OF THE PASS THROUGH TRUSTEE'S CERTIFICATE OF AUTHENTICATION]

Dated:

This is one of the Certificates referred to in the
within-mentioned Pass Through Trust Agreement.

_____________________,
as Pass Through Trustee

By:______________________________
Authorized Officer

A-6
69

EXHIBIT C

FORM OF DTC
LETTER OF REPRESENTATIONS

SCHEDULE I

Equipment Notes
to be Issued under Principal
the Indenture: Amount Maturity
---------------------- ---------------- ---------------

On the Issuance Date $

Subsequent to the
Issuance Date

Total Notes $

Equipment Trust Certificates to be
issued under
Equipment Trust Agreements

On the Issuance Date

UTC $

Subsequent to the
Issuance Date

UTC $

Total ETC's $

Total Notes and ETC's $

SCHEDULE II

ETCs
to be Issued under Principal
Equipment Trust Agreements Amount Maturity
-------------------------- ---------------- ---------------

Total $

Reconciliation and tie between Pass Through Trust Agreement _____ dated
________ and the Trust Indenture Act of 1939. This reconciliation does not
constitute part of the Pass Through Trust Agreement.

Trust Indenture Act Pass Through Trust
of 1939 Section Agreement Section
------------------- -------------------

310(a)(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8
(2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8
(3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2; 6.3 (a) & (b)
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8; 7.9; 7.10
(c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
311(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.18
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.18
(c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
312(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.9; 8.1; 8.2
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4
(c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4
313 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3
314(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(c)(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2
(2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2
(3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(d)(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(e) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2
315(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1(a)
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2
(c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1(b)
(d) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1(c)
(e) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6
316(a)(last sentence) . . . . . . . . . . . . . . . . . . . . . . . . . 1.4(c)
(1)(A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4
(B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5
(2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inapplicable
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7
(c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4(d)
317(a)(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3(a)
(2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3(b)
(b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.13
318(a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.7

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