You have to remember that the Yonge Line will remain the preferred n-s corridor for most travel in Toronto, as it offers better access to a wider area of downtown and amenities to the north.
It's hard for me to imagine how or why a customers originating from east of Leslie would favour the Yonge Line over the Ontario Line to get Downtown. That's another 5 kilometres stuck in a mixed traffic bus. The Ontario Line
will get them Downtown faster. And even if it didn't, I'm sure most of them would still pick the OL just out of passenger comfort.
The Yonge Line will remain very busy, but at peak hours it'll be reduced to serving customers from York Region and the narrow band of Toronto residents between the OL and Spadina Line (which, to be fair, is the densest part of the city).
if it does end up hitting 30k+ in 2077.. we could always just build a third subway line
There is no way it'll take 55 years to hit 30,000 pphpd. Not unless something goes catastrophically wrong with Toronto's economy.
With a capacity of 30,000, and an extension to Sheppard moving
at least 20,000 pphpd, that leaves 10,000 pphpd for growth. That sounds like a lot, but to put that in perspective, that's equivalent to just 2/3rds the capacity of the Eglinton Crosstown (which is itself a line that some people insist doesn't have capacity for long term growth).
The idea that 55 years worth of employment growth would produce only another 10k pphpd is a complete fantasy. Not unless our economy is in the toilet. If our economy is strong, we'll fill up that 10,000 pphpd with quickness.
And please keep in mind that nothing I've said here even factors in transfers from RER at East Harbour. That's at least thousands more OL seats being taken up at peak hour. So in reality we have even less than 10k pphpd for growth.
Toronto exceptionalism at it's finest is almost every other large city on the planet getting by just fine with subway capacities in the 30k range, by building new lines when the existing one gets overloaded (as Toronto is doing today), but nope, in Toronto, we have to build mega-subways to accommodate 100 years of growth. Nowhere else does that.
I'm all for new subway lines. I've said before that I believe that we should be targeting a third line downtown by 2040. However, Toronto really doesn't have the greatest track record here.
Even putting that aside though, the additional capacity is useful just for flexibility into the future. Lower capacity today means we'll have less flexibility tomorrow.
Had the OL been designed with extra capacity, extending it into York Region would've been rather trivial and inexpensive. We could've seen that extension to York Region done by 2040. But now that's just not going to be a possibility (not without catastrophically low employment growth). And it's not like we can just trivially just build another subway line from Downtown to York Region either; it would almost certainly be too expensive to be worthwhile. These capacity constraints mean that a subway from Downtown to eastern York Region has gone from a cheap, no brainer extension, to something that probably isn't going to ever happen.
Likewise, it's unlikely that the OL could serve deep into the west end of the city either, due to capacity constraints.
