The provisions of sections 14 and 15 shall apply to the opening of the following works if they form part of, or are directly connected with, the metro railway used for the public carriage of passengers and have been constructed subsequent to the giving of a report by the Commissioner under section 15, namely:--
         (a) opening of additional lines of metro railway;
         (b) opening of stations and junctions;
         (c) re-modelling of yards and re-building of bridges; and
         (d) any alteration or reconstruction materially affecting the structural character of any work to which the provisions of sections 14 and 15 apply or are extended by this section.