(2) All moneys on deposit from time to time in the Regional Light Rail Extension Bond Account, together with all investment earnings thereon, shall be pledged and are continuously appropriated to the payment of the bonds issued under ORS 391.140. All investment earnings on moneys on deposit from time to time in the Regional Light Rail Extension Bond Account shall be retained in that account and applied to pay the principal of and interest on bonds issued under ORS 391.140. [1991 c.575 §3]