Ala. Code § 37-13-13
In the discretion of the authority any bonds may be issued under and secured by an indenture between the authority and a trustee. Said trustee may be a private person or corporation, including (but not limited to) any trust company or bank having trust powers, whether such bank or trust company is located within or without the state. In any such indenture or resolution providing for the issuance of bonds, the authority may pledge, for payment of the principal of and the interest on such bonds, any of its revenues to which its right then exists or may thereafter come into existence and may assign, as security for such payment, any of its leases, franchises, permits and contracts; and in any such indenture, the authority may mortgage any of its properties, including any that may be thereafter acquired by it. Any such pledge of revenues shall be valid and binding from the time it is made, and the revenues so pledged and thereafter received by the authority shall immediately become subject to the lien of such pledge without any physical delivery thereof or further act. The lien of such pledge shall be valid and binding against all parties having claims of any kind in tort, contract or otherwise against the authority, irrespective of whether the parties have actual notice thereof, from the time a statement is filed in the office of the judge of probate of the county in which is located the principal office of the authority (as specified in its certificate of incorporation) and any other county in which any part of the property, the revenues from which are so pledged, is located. Such notice need state only the date on which the resolution authorizing the issuance of the bonds was adopted by the board, the principal amount of bonds issued, a brief description of the revenues so pledged and a brief description of any property the revenues from which are so pledged.
In any indenture or resolution authorizing the issuance of bonds and pledging for the benefit thereof revenues from any of its railroad properties and facilities, the authority shall have the power to include provisions customarily contained in instruments securing evidence of indebtedness, including, without limiting the generality of the foregoing, provisions respecting the collection, segregation and application of any rental or other revenue due to or to become due to the authority, the terms to be incorporated in any lease agreement respecting any property of the authority, the maintenance and insurance of any building or structure owned by the authority, the creation and maintenance of special funds from any revenue of the authority and the rights and remedies available in the event of default to the holders of the bonds or the trustee under the indenture, all as the board shall deem advisable and as shall not be in conflict with the provisions of this chapter. If there be any default by the authority in payment of the principal of or the interest on the bonds or in any of the agreements on the part of the authority that may properly be included in any indenture securing the bonds, any holder of bonds or coupons, or the trustee under any indenture if so authorized in such indenture, may (in addition to any other remedies herein provided or otherwise available) either at law or in equity, by suit, action, mandamus or other proceedings, enforce payment of such principal or interest and compel performance of all duties of the board and officers of the authority, and shall be entitled as a matter of right, and regardless of the sufficiency of any such security, to the appointment of a receiver in equity with all the powers of such receiver for the operation and maintenance of the property of the authority covered by such indenture and the collection, segregation and application of revenues therefrom. The indenture may also contain provisions restricting the individual rights of action of the holders of the bonds and coupons.
Ala. Code § 37-13-13 (1975)