Toronto Subway: Began in mid-50's, expanded in 60's, 70's, and 80's. Originally envisioned as the solution to transportation problems in the city. Hopes foundered on arguments between
leading population growth, and
following. No longer believed to be adequate for the need, but better than nothing. With the end of provincial subsidies, thanks to
Mike Harris, much more expensive.
(The original subway from Eglington to Union Station was mostly trench built, as Whywait? writes. The first new leg, from Union Station to St. George, was mostly tunnelled. You can see this in the shape of the underground itself: St. Andrew, St. Patrick Stations are rounded. It was tunnelled, I believe, because it was much too much trouble to make tunnelles in the business district, and near The Pink Palace. The Spadina and further north subway, is mostly built above ground as I remember.)
Montreal Metro: Unique in that it travels on rubber wheels. Is without the tooth-wrenching screeching all metal-wheeled subways do. Built to reach the World Exposition held in 1967, it joins islands and suburbs.