Second, Metrolinx is dangerously putting all it's eggs in one basket by having every single RER line converge at Union. VIA is moving to HFR and with RER going to a minimum of 6,000 trips a week, Union will quickly become too congested with both trains and people.
Metrolinx owns the Union Station platform level and every inch of track used by Via from there to Pickering. Take a wild guess who calls the shots on how its used.
Then consider that one of these two government agencies already has a fully funded project with $13.5 billion in hand and shovels in the ground, and the other is still sketching up a concept and trying to assemble a business plan so as to land its first HFR dollar.
Via can't just start wake up one morning and run three times the trains and steal all the available capacity out from under Metrolinx's nose. If HFR becomes a real thing (and I'm reasonably optimistic it will), and threatens Metrolinx's RER plans (and I'm reasonably optimistic it won't), you can be damn sure they'll either make Via pay for additional capacity upgrades or tell them politely that two-thirds of their trains will have to come to a dead stop in Pickering.
That number will only soar as the RER system increases frequency to meet demand and other inevitable line come on stream like Richmond Hill and especially Milton. RER could easily need 15,000 trains/week by 2040.
Um, I'm pretty sure there are a lot of gentlemen in very expensive pinstriped suits at CN and CP headquarters that don't think its "inevitable" that RER will come to the Milton and Richmond Hill lines. There's the small matter of multiple billions of dollars of further investment that would need to be closed first.
But fine, let's assume we wave a magic wand and get the same kind of train volumes the future Barrie line will have on two more GO lines. That presumably grows the future GO scenario from 6000 train trips a week to the ballpark of, what, 7,500 trips a week?
Now you're saying RER will "easily" get to 15,000 trains/week 15 years after launch? That's another doubling of train frequencies on all seven lines. That's another couple of billion dollars worth of expansion. What, pray tell, convinces you that there is "easily" demand for so much service and that it would be both economic and inevitable for us to get there?
This is made worse by the fact that increasingly more people will need to get beyond 4 blocks of Union creating huge stresses for the already overburdened Yonge Line.
So let me see if I follow here. In order to bring people to destinations further than 4 blocks from Union, we need to bring them to an interchange station 4 blocks from Union, so they can go to places further than there on the very same Yonge Line? (And counterpeak on it in either scenario.)
How on Earth are all these people and thousands of trains going to be able to negotiate just one station?
Assuming they pop into existence? Ask the Japanese. Nicely.
This is made MUCH worse by the fact that if there is an accident or emergency at Union, the entire RER. GO commuter, and VIA rail system would come to a screeching halt effectively immobilizing the city.
Shh. You might scare
these guys, who spent decades longing for a Union Station that would bring together all their S-bahn, region and intercity trains into a single station, but were blocked by pesky politics. So as soon as they got the chance, they spent billions creating
one. But they don't know anything about passenger rail.
A second downtown tunnel as part of DRL down Queen would offer a much needed secondary route thru the core to avoid such inevitability but also greatly relieve the stresses of the soaring number of both trains and people that Union will see over the decades to come.
I actually think a blended RER/local tube under Queen is a pretty cool idea. But you're really, really abusing the word "inevitability".