I just thought of something from last week that I forgot to post.....last week I rode an AMT train......it was a bilevel Bombardier car...one of the new ones and while it was similar in many ways to the GO trains we use....there are obvious differences and one of which is that it appears each car has extra doors...some for high platforms and some for low platforms.....both my departure station and arrival station were low platforms so I never saw if they actually use both doors but (aside from nearly missing my station in confusion trying to use the wrong door) it seemed like a really flexible solution.......one that (if they were used on UP for example) would allow for, say, a weekend addition of the Etobicoke north station as a gathering/car pool/park and ride station for folks in the NW GTA without having to do any platform work.