Ala. Code § 11-81-174

Any bonds issued under this article solely for refunding purposes shall, unless it shall be otherwise provided in the authorizing proceedings providing for the issuance thereof, be secured to the same extent and have the same sources of payment as the bonds refunded thereby. Unless otherwise provided in the authorizing proceedings providing for the issuance of any such bonds issued solely for refunding purposes, the holders of such bonds shall be subrogated to all the rights and powers of the holders of the bonds refunded thereby.