To add to your rough crayoning Lines 7 and 8 could have an interchange station (possibly replacing King-Liberty) at the intersection/area of Wellington & Strachan, where the Kitchener and Lakeshore corridors meet. Here you could have Line 8 switch corridors and terminate at Union. Big bonus of...

I don't think a merger is unreasonable, but I think keeping them seperate while making the UPX a new dedicated electrified line is enough to transform the west end. Keeping this new hypothetical UPX and the OL seperate gives a huge amount of flexibility to a western OL extension - whether that's...

This is a key component of my transit fantasy map - converting the UPX into a new electrified line with tight headways. I think that having a commuter train that serves the airport is more needed than an airport train that is overloaded with commuters. Union, Spadina-Front, King-Liberty...