13As from the appointed day, the reference to the Post Office in section 6 of the [1887 c. 65.] Military Tramways Act 1887 (which requires the insertion, in certain cases, in a provisional order made under that Act of provisions for the protection of its telegraphs), and any reference to it in a provisional order so made which is in force at the beginning of that day, shall be construed as referring to the Corporation.