The canada line uses trains that are only 40m long. (compared to 140m for the new Toronto rockets) This is a huge difference in capacity, and quite frankly if the DRL was to be constructed with 40m long ICTS trains it would be over capacity on opening day. mind you trains with that capacity also allow for much cheaper construction as platforms can be 50-60m long instead of 160-170 for Toronto. there is also the fact that the Canada Line was built Cut and Cover, which could questionably create total traffic havoc in the city for years on end in Toronto.
Translink claims the CL's EMUs can hold ~167 people per car and designed the stations to accommodate 3 car trains. If you had trains running every 90s, which is hardly innovative, that would work out to a peak capacity of about 20k pphpd, nearly a 15% cushion over the biggest estimate for a DRL and a 70% cushion on the simple Pape-King-Downtown alignment.
While cities like Montreal or Vancouver definitely build lower capacity transit systems, the capacity gap isn't as big as you let on and certainly not relative to our capital costs gap. More importantly, there really aren't any routes left in Toronto which have the potential for >20k pphpd.
There is a persistent trend on this board to WAY overestimate capacity requirements and I've got no idea where it comes from. What do people here really think peak demand on a DRL would be? In another thread, rbt guessed 45k pphpd. nfitz just said it would be 'dangerous' not to plan for more than 20k, since one day the DRL may stretch from the 905 to downtown. When subways cost 800m/km or whatever in 2040 I will literally eat my shoe if a DRL, if it even exists, is extended anywhere. As it is I'd be amazed if we got anything more than a Pape-downtown segment as long as prices are coming in at 450-500m/km.
Personally, my opinion based on TTC estimates for a 'full' Eglinton-Pape-King/Queen-Dundas West DRL, by 2050 demand would be in the range of 20-25k. I think the best way to meet that goal is to design a system based around smallish trains running at the highest frequency physics will allow. Bombardier claims it can reach about 48 trains per hour, but 40 is definitely achievable.
Also, re cut/cover. For starters, a substantial portion of the Canada Line was actually bored through downtown Vancouver, but whatever. More importantly though, there's no reason to think cut/covering a section like that along Pape would create 'traffic havoc for years on end' for the City. A good chunk of Toronto wouldn't see anything wrong with tearing down the Gardiner permanently, yet apparently closing a secondary 4 lane road in East York for a couple years would create some kind of super traffic apocalypse! It's totally dissonant. I doubt anyone here would react in horror if King or Yonge or Queen were permanently turned into pedestrian/transit malls, why couldn't Richmond or Wellington or Adelaide or Pape be closed for a few years to build an obviously beneficial piece of infrastructure?
Half elevated as well. Elevating a line typically costs $70ish million a km, so that makes the tunnelled portion more than 200. You are probably looking at 250-300m a km to build the Underground portion of the Canada line with 120m (3 car) trains. This is in much simpler geography than what the DRL requires, (no sharp turns, no mega bridges, no tunnelling around an underground walkway system, etc.) by the time all that is factored in, you are looking at almost no cost savings compared to HRT (standard toronto subway) when built cut and cover, at which point you should probably opt with the $10 million more a km, and built HRT, to allow for hugely larger capacity.
Hugh? Alot of these numbers don't make any sense at all...
'no mega bridges:' The Canada Line has several river crossings. One under False Creek, one along the North Arm Bridge and another along the Middle Arm Bridge.
"to build the Underground portion of the Canada line with 120m (3 car) trains:" A three car train on the Canada Line would be 60 meters, and the system was designed to accommodate that.
Your route costs are extremely bizarre. Using your numbers, the Canada Line would have cost nearly 200m/km. And, if elevated lines cost 70m/km, why does at grade LRT here cost 100m/km, and why don't we just elevate the DRL along the rail corridor and in Thorncliffe/Flemingdon?
You keep mentioning very real ways the TTC could save money (cut/cover, elevating, single tunnel bores) but then just discount them as impossible.
Also, just using your numbers (250m-300m), that's STILL substantially less than what the TTC estimates for the DRL (450m-500m). That's 50-100% premium here!