Nothing in this Article shall impair the right of the City to require the holder of a franchise or other person, required by ordinance or otherwise to pave a portion of street, to move any facility at his or her own expense or to improve a portion of street, to carry out his or her obligation without expense to the City. For this purpose, elimination of grade crossings is a public work and improvement. No duty, express or implied, of the holder of a franchise, contract or permit shall be impaired by amendments to this Chapter subsequent to the grant of franchise, contract or permit. [June 2, 1913, subdn. j, new sec. 372 1/2; 1928 pub., sec. 274; 1942 recod., sec. 9-410; rev. Nov. 8, 1966; am. Nov. 3, 1992.]