I think Karl's post bears repeating, so I will post it here as well.
Adam said:
The LRT tunnel is much larger than the subway tunnel due to OCS and I am willing to bet that the underground portion will cost just as much as subway if not more.
I wouldn’t say “much†larger; the difference in diameter is less than 1 metre (5.2m for subway (5.4m if it’s a curvy alignment like TYSSE), and 6m for LRT). Yes, it is absolutely true that the LRT will incur more spoil costs and more concrete for lining the tunnels, but remember that there are some additional requirements for subways that counter-balance the savings against LRT in spoil and concrete. Subways require longer X-overs, longer pockets, and bigger station boxes (although the station box difference is marginal given the huge maintenance/service areas being put in to the Eglinton LRT stations, hugely disproportionate compared to subway stations as far as I can tell; they must go well beyond ventilation requirements for their size). I think the cost difference is pretty small, but I’d put subway at a slight notch higher in cost than underground LRT.
James Bow said:
Between Black Creek and Brentcliffe, we are building a subway. Plain and simple. Yes, it’s being operated by LRT vehicles, but it is in every way, shape and form, a subway. It’s underground, like a subway. Using three-car LRT trains at frequent intervals, it will have a higher capacity than the current Sheppard subway and likely carry more passengers. It will have the speed of a subway and possibly be even a little bit faster, since the cars won’t be as heavy, will be powered by 750 Volts instead of 600, and may accelerate faster.
I have to disagree with you on that; it is not “in every way, shape and form, a subway.†I have noticed over the course of the election that people have been told, supposedly by someone from (or on contract with) the TTC, that Eglinton’s tunnel is being built to subway spec. If it actually is someone from/with the TTC, this is very troubling because it is irrefutably false, but only transparently so if you know anything about engineering. This is effectively preying on the general public’s lack of specialized knowledge, and that bothers me
a lot. This should not be tolerated, and the City and TTC should go out of their way to set the record straight that this is not being designed to subway spec (unless there have been substantial and dramatic changes since the EA was approved, which I doubt). This kind of misinformation ultimately only undermines any support for LRT anywhere.
There are a number of elements with the tunnel that make it outright impossible to be served by subway in future. These include:
- Grades (4.x% and 5% grades can be found in the Eglinton tunnel’s proposed design, but 3.5% is the max for HRT)
- Turnouts at X-overs and pockets (turning radii requirements differ dramatically between the two technologies)
- Pocket lengths (far too short for subway in the Eglinton tunnel’s proposed design; only fits LRTs)
- Vertical curvature (minimum “K†value for subway is 35m, but many instances of 25m in Eglinton tunnel, and one at 23m)
This is not a small list, especially when you consider directly related vertical alignment requirements that result in a long series of domino effects. Given the money involved, and the relatively small difference in cost, it should be a subway-compatible tunnel, platform height issues notwithstanding. In my opinion, the design proposed currently for the Eglinton tunnel is unacceptable, as it is not “future proof.â€
I would also disagree with Sheppard’s capacity being lower than the Eglinton LRT’s would be. Even with 4-car trains and no ATO (Sheppard actually does have ATO signals already, just not ATO rolling stock), its practical capacity (if you add rolling stock as required (a non-issue since TTC will soon have a surplus of T1s after TRs are delivered)) is 17,000! Given that the station boxes are roughed in for full-length 6-car trains, there’s no major impediment to a capacity of ~25,000 on Sheppard with T1s (higher still with TRs), truth be told. Not that that would ever be needed, seeing as it only carries 5,000 now (hence its $10M loss per year), but its capacity is far higher than the Eglinton LRT can ever hope to be, with its maximum at 13,000.
Given that Sheppard carries 5,000 now, I find it hard to believe the projections of only 5,400 for Eglinton in 2031. If a proverbial “subway to nowhere†can net a demand of 5,000 today, one that actually goes somewhere will surely hit higher than 5,400 in 20 years from now.
As for the speed, although it is quite probable that the acceleration rates will be superior on the LRT vehicles, the real reason that the Eglinton LRT will be faster than its Bloor-Danforth equivalent is because it has far too few stations along the underground part of the line. This issue was glossed over with an unacceptable frame of reference, comparing the 10-or-so-km Eglinton tunnel with the entire 26km Bloor-Danforth subway, which is itself a piece of repeated misinformation throughout the consultation process.
