The Édouard-Montpetit light-rail REM station in Montreal is the deepest in the network, and the second deepest in North America when it comes to underground public transportation. It's 72 metres deep which is the required depth needed to reach the Mount Royal tunnel. This is part of the network extension into the Deux-Montagnes line. The network now has 19 stations fully operational. »»» Subscribe to CBC News to watch more videos: http://bit.ly/1RreYWS For breaking news, video, audio and in-