(a) If an authority should realize a surplus, whether from operating the intermodal facilities and other facilities or leasing it or them for operation, over and above the amount required for the maintenance, improvement, and operation of the intermodal facility and other facilities and for meeting all required payments on its obligations, it shall set aside the reserve for future operations, improvements, and contingencies as it shall deem proper and shall then apply the residue of the surplus, if any, to the payment of any recognized and established obligations not then due.
(b) After all the recognized and established obligations have been paid off and discharged in full, the authority shall, at the end of each fiscal year, set aside the reserve for future operations, improvements, and contingencies as prescribed in subsection (a) and then pay the residue of the surplus, if any, to the counties and municipalities in direct proportion to their financial contribution, provided that no such distribution of said residue of the surplus shall violate United States law or the terms of any deed, grant agreement or other agreement with the United States.