Rainforest
Senior Member
I believe the final configuration of Line 4 is most likely to be Sheppard West Station on Line 1 to McCowan Station on the SSE.
I find it highly improbable it will extend beyond either point; though it is not inconceivable it could make a veer out to provide a station in Malvern.
Isn't that the downside of keeping the existing rolling stock on Sheppard? If we want it to be a crosstown line, or perhaps a cross-region line, then a lighter / more agile technology would probably work better. The line could connect to the Lakeshore East GO in the east, and reach Pearson and/or Mississauga Centre in the west.
The cost of converting the existing 5.5 km is constant, while the saving on the new sections is incremental. More length, greater amount of saving. If the total length is 35-40 km, then the saving should outweight the conversion cost.
However, I understand the political obstacles to conversion. It is hard for any government to commit to a 30+ km line at once. Short extensions are easier to fund, but then the benefit of conversion isn't realized until it is too late. Once we have a full-fledged subway from McCowan to Sheppard West, noone is going to convert it to something else.