77. Notwithstanding the temporary stopping up or diversion of any highway pursuant to article 8, a company shall be at liberty at all times to execute and do all such works and things in, upon or under any such highway as may be reasonably necessary or desirable to enable it to maintain or use any apparatus which at the time of the stopping up or diversion was in that highway provided that this provision shall not apply where alternative apparatus has been installed to replace the apparatus in question and is in operation or the apparatus is otherwise redundant.