One-fifth of the cost of constructing the said bridge (in line of Benning Road over the Anacostia River) and approaches shall be borne and paid by the Washington Railway and Electric Company, its successors and assigns, to the Collector of Taxes of the District of Columbia, to the credit of the District of Columbia, and the same shall be a valid and subsisting lien against the franchises and property of the said railway company and shall constitute a legal indebtedness of said company in favor of the District of Columbia, and the said lien may be enforced in the name of the District of Columbia by a bill in equity brought by the Mayor of the District of Columbia in the Superior Court of the District of Columbia, or by any other lawful proceeding against the said railway company; provided further, that after the completion of said bridge and approaches authorized by the act of June 29, 1932 (47 Stat. 355) no street railway company shall use said bridge or approaches until the said company shall have paid to the Collector of Taxes of the District of Columbia a sum equal to one-fifth of the cost of said bridge and approaches, which sum shall be paid to the Collector of Taxes of the District of Columbia for deposit to the credit of the District of Columbia.
