D.C. Code § 9-1203.04
Subject always to the approval of the Council of the District of Columbia, all such railroad tracks, turnouts, branch tracks, spurs, and sidings may be located and constructed in, upon, along, and through public grounds, space, and streets of the United States and/or of the District of Columbia as same are now or may hereafter be located and established; provided, that except as in §§ 9-1203.01 to 9-1203.09 expressly authorized no tracks, turnouts, branches, spurs, or sidings shall be constructed along or through South Capitol Street or 1st Street Southwest in the north and south direction, at grade or otherwise, but each of said streets, with prior approval of said Council of the District of Columbia, may be crossed to such extent as may be necessary for the establishment of adequate railroad facilities; provided further, that no permit for the construction of tracks, turnouts, branches, spurs, or sidings shall be issued with respect to squares 600, 602, 604, 606, 608, 610, and 612, or any of said squares, until the particular square or squares for which a permit is sought shall have been zoned industrial; and provided further, that the plans for any building fronting on Canal Street from the Anacostia River to P Street Southwest shall have the approval of the Fine Arts Commission as to height and design.
D.C. Code § 9-1203.04