If we build the line the way the city was planning it will likely cost something close to twice as much. Sure using bigger trains On the same alignment would *only* cost a billion or two, but again this is insane that we are talking about sums of money like that. We have a problem when stuff is costing this much. 1-2B should be enough to add 5K ppdph to the Yonge Line, or ATC to Line 2, or starting building another central rapid transit line.
I don’t really agree that being at 90% forces a line to not run well, it’s really a matter of improving our operations. Another case where yeah we could overbuild and this project would be ok, or we could improve our operational practices and every project we do from now on and all our existing lines would benefit.