Note that the new lines are not TTC lines, they are Metrolinx lines. And Metrolinx is also building LRT systems in other cities that use standard gauge, so it d

Note that the new lines are not TTC lines, they are Metrolinx lines. And Metrolinx is also building LRT systems in other cities that use standard gauge, so it definitely makes the most sense to stick with standard gauge instead of switching to the TTC's unique gauge. Now imagine that Metrolinx's GO trains also used a non-standard gauge? Not only could they not share track with freight trains, or even Via Rail, but simply delivering the train cars from where they are manufactured in Thunder Bay would be a nightmare. As it is, they're just attached to a freight train and pulled along like any other car, and I've even seen them on a CP freight train.