65 ILCS 5/11-12.1-6

The provisions of this Division 12.1 and of any ordinance or other proceeding authorizing the issuance of bonds under this Division 12.1 shall constitute a contract with the holders of such bonds and any holder of a bond or bonds or any of the coupons of any bond or bonds of such municipality issued under this Division 12.1 may by action, mandamus, injunction or other proceeding, enforce and compel the performance of all duties required by this Division 12.1 including the application of income and revenue from such mortgage loan fund and the faithful performance of any agreement or collateral trust indentures securing the payment of such bonds.