IMO
Sheppard East LRT should be a subway if cost of LRT goes more than $1.6 billion
Eglinton Crosstown LRT should be a subway if cost goes more than $6 billion
At that point there is just no point in going with LRT for such a high capital.
The only problem is, what happens when the cost goes over that mark halfway through construction? Do they stop and start over again? If it's a mistake, the TTC should do their research properly, so that they find out it's a mistake BEFORE they start building, not halfway through. The cost of Transit City as a whole has nearly doubled since it was first proposed, and that's with only half the lines in really detailed levels of planning, and really only 1 project even started construction. That doesn't give me much optimism that the TTC actually did their homework and accurately projected the costs. It's looking more and more like they budgeted for a bare-bones system just to get it passed, and then they beefed it up to what they were actually looking for all along (which was double the cost).