When better batteries are invented no trains may need any overhead wires. Hopefully they could refit the current streetcars with such batteries and then take the overhead wires down afterward.

When it opens hopefully they'll incorporate some convenient pay system crossing the boundaries, certainly not have the current setup where it's a TTC fare at the 905 stations.

Or during rush hour short turn some trains at East Harbour.

Also what is to become of the RT stations do they get preserved to appear in commercials and open up on Doors Open. And save a trainset or 2.

The Line 1 extensions could be extended even further to go around Lake Simcoe and then connect with each other on the north side of the lake to create a gigantic belt line.

And what route to the airport, following the UPX line perhaps.

It needs more east west routes like on Major Mack or 16th Avenue perhaps.

Perhaps the Scarborough wing of Line 2 can be split off from it and parallel the GO route south of Danforth to Gerrard station and add a GO station there, and then continue west along Gerrard to Dundas station and St. Patrick. But not have stops at every bus route south of Danforth, that's...

People exiting from the Ontario Line to go outside will still have to go up 4 flights of stairs if they're not transferring.

City Streets by Terry O'Hagan, on Flickr

Queen Street east could become full of skyscrapers and gentrification.

If it gets too crowded then that's an excuse to add more downtown lines, perhaps one that serves Dundas and Gerrard.

If they're going to spend $50 million on it they should at least keep it when the SSE opens.

The 7th car could be inserted in the middle of the train.

There could be branching that creates a loop and merges back again into one line, like the Northern Line.

In 30 years they’ll shut down the whole line and then build a new underground subway to replace it, and have shuttle busses replace the line until the new subway opens.

Instead of referring to the weight of the vehicle light could instead refer to lighter service than you'd expect from a subway.

Could have at least gone with the TTC colours.

They could also tunnel under Eglinton East so Line 5 could avoid the on street section.

If most of the line is going to be off the road they should have gone with Ontario Line tech, which would have also assured that none of the line would be on the road.