I once watched the TTC (Toronto Transit Commission) close a section of doorways from the street into a station (Runnymede) to replace a small section of tile floor on the inside. It was about 10 ft x 4 ft section, it took somewhere around 2.5 years. After they ripped out the tile on in the first week, I didn't see anyone until it was done 2.5 years later. It took about another 2-3 weeks to remove the plywood and caution tape so people could use the doors again instead of having to walk around to another entrance.

The Eglinton line has taken 15 years and good portion is above ground where they don't even have to tunnel. Still not done, probably another 15-20 years left.

It's why I laugh when Carney proposes a high speed rail link between Toronto and Montreal, it would take a couple of centuries to build.

Some cities and countries are inept, they can no longer build anything because of the bureaucracy and the need for consensus from 100000 different interest groups.