Security for the Notes; First Mortgage Bonds. (a) The Notes of each series shall be secured by an equal principal amount of the related First Mortgage Bonds issued by the Company under the Mortgage Indenture to U.S. Bank National Association, as collateral agent for the holders of the Notes. The First Mortgage Bonds will rank pari passu with all other existing and future first mortgage bonds issued pursuant to the Mortgage Indenture.