§ 198. Contracts for the adjustment of payments due certain cities. The board of estimate and apportionment, or if such board do not exist, the local authorities which have power to make appropriation of moneys to be raised by taxation, in any city having a population of three hundred thousand or more, shall have the power in their discretion, to enter into a contract or contracts on behalf of the city with any railroad corporation or corporations owning or operating street surface railroads or other railroads in such city, for the purpose of adjusting any or all differences now existing between such corporation or corporations and such city with respect to car license fees, percentages upon gross earnings, rentals and any other payments, other than taxes upon real and personal property, and capital stock, payable or claimed to be payable to the city under existing acts of the legislature, municipal ordinances, grants by, or contracts with, the municipal authorities or otherwise; and any such contract may provide for the payment of an annual amount to be ascertained as in such contract provided in lieu of any or all payments of any of the classes hereinbefore mentioned, other than taxes. Any such contract which shall be with a corporation operating lines of railroad by lease may provide for an annual payment, to be ascertained as in such contract provided, which shall be in lieu of any or all of the payments of any or all of said classes, other than taxes upon real and personal property and capital stock, which would otherwise be payable in respect of the leased lines so long as the lease or leases thereof shall continue. The annual payments provided for in any contract made under the authority of this section shall, so long as such contract is in force, supersede the payments which would otherwise be payable by the corporation or corporations making such contract and in lieu of which the annual payments provided for in such contract are substituted. Any contract made hereunder may, with the approval of the municipal authorities by whom the contract was made or their successors in office, be modified from time to time by the parties thereto for the purpose of meeting changed conditions. No contract shall be made or modified hereunder without the written consent and approval of the mayor and of the comptroller or other chief financial officer of the city.