Sorry Guys, but you are living in a dream world to extend the platforms.
Cost would be out of this world as well take over 100 years to do it. You are looking at about $20-$50 million per station end.
You would have to tear down buildings at each end of the station because their foundation would be in the way and we are not talking small buildings.
What TTC should have done is build the new Subway train 490' long and it would have come in 7 sections. It would meant the cars would be shorter than the T1's, but still do what the the new subway train is going to do with more riders.
This is where the ATO comes into play as you will need it to stop the train at the right spot at the stations.
Doing this expansion of Platforms will also stop service to tear out some of the existing wall as well supporting the tunnel structure. We are talking months.
It would be cheaper to build a new subway line than do what you want to do.
I have call for a Queen St Line that would run from Nevile to Roncesvalles. The line would turn north at Nevile and go up Victoria and Woodbine to 16th St in York to the east and to Jane St to the west that would go up to 16th st also. Both legs would connect with the BD, Eglinton, Sheppard, Steeles and 16th St east-west subways lines. Here is the DRL that ppl have been calling for.
The only place you can extend platforms are at Warden, Victoria, Old Mill, Keel, Kipling, Lawrence, Glencarin, Yorkdale, Wilson, Rosedale, Eglinton W, Summerhill and Davisvale with very little problems.
All new subways will be 3 track using center platforms. The 3 track will be a out of service track, but most of all an express track. I would like to see the new lines 4 track, but cost is the issue as well demand.
The Queen Line would only see haft the station that the BD see now as 501 would remain in service after the subway is built to deal with 300m stops.
Stops for Queen are Roncesvalles, Lansdown, Dufferin, Bathurst, Spadina, University, Yonge, Parliament, Broadview, Coxwell, Woodbine, and Nevile.