Kyle Campbell said:
Any idea on what the DRL/RL would actually get as an official name? Also, if the RT is gone at that point, would they reuse the number 3 for the line, or leave a gap and just have line 6? I can't think of any other city in recent memory that's closed an entire line....
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Leo_Chan said:
Line 3 - Relief Line.
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Kyle Campbell said:
Really? It's going to show up on maps as that?! I can hear the comedians telling jokes now.....
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Guys, any idea on how many washrooms the Relief Line will have? With that name, it oughta have more than just one or two.
 
TheTigerMaster said:
My two-cents is that the Spadina Subway Line should be built as an underground LRT line from Bloor down to Queens Quay, where the LRT would continue to Union Station on the existing infrastructure. The Relief Line would continue to the west end (as traditionally planned), intersecting the Spadina Subway at Queen & Spadina.
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TheTigerMaster said:
I've been curious about the potential for a Spadina Subway for some time now. Once the DRL is complete, the 510 will be the most used surface route in the city. With streetcar ridership expected to double in the coming decades, along with enormous increases in Downtown employment and population, I struggle to see how the 510 can continue to efficiently operate. Furthermore, long term projections show that the University Line downtown will also face capacity constraints in the upcoming years; a Spadina Subway Line could act as a University Relief Line to a certain extent.

My two-cents is that the Spadina Subway Line should be built as an underground LRT line from Bloor down to Queens Quay, where the LRT would continue to Union Station on the existing infrastructure. The Relief Line would continue to the west end (as traditionally planned), intersecting the Spadina Subway at Queen & Spadina.
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That would provide plenty of capacity for the foreseeable future. You can get to 26k people per hour in an LRT subway (based on the final capacity of the confederation line with 120m platforms) though in the much shorter term, would the TTC consider running double streetcars on the surface? The flexities can run coupled, and given the route is already segregated it should be possible to lengthen the existing platforms. The problem of course would be Queens quay and the existing loops at Union and Spadina, but it could be done.
 
Another idea for the relief line... Would the TTC consider using an entirely different rolling stock? With a narrower train than the TRs you can use a single bore tunnel which would bring costs down and maybe funding the whole line more likely.
 
Kyle Campbell said:
With a narrower train than the TRs you can use a single bore tunnel which would bring costs down and maybe funding the whole line more likely.
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Why is that?

More specifically, how small does the single bore need to be to adequately fit between building foundations on Queen leaving sufficient buffer soil between the bore and the foundation to continue adequately supporting the foundation (prevent future foundation failure)? Is that difference in bore size really only a couple feet?

Also, given that a single bore needs to be deeper (the bottom will be lower as the top of the tunnel has a limit), how much deeper (and at what cost) do the deployment/extraction shafts around the existing subway lines (like Queen Station) need to be?


The big advantage to a single bore, IIRC, is severe reduction in the cost of the stations (since they can be built into the tunnel area) at a non-trivial increase in the cost of the bore. Madrid is taking this to an extreme and minimizing vertical digging by using elevators only for station access; no escalators. Covent Garden (London) hasn't exactly been a success with that configuration.
 
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rbt said:
Why is that?

More specifically, how small does the single bore need to be to adequately fit between building foundations on Queen leaving sufficient buffer soil between the bore and the foundation to continue adequately supporting the foundation (prevent future foundation failure)? Is that difference in bore size really only a couple feet
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It's not that it's impossible to have a wider single bore tunnel, otherwise you wouldn't have single bore car tunnels. It's that the savings dissapear the wider it gets. 2.5 to 2.6 m trains seem to be the norm for single bore, such as Madrid, Paris, and here in Canada Montreal and Ottawa
 
I think subways should be built in area where you know the population is going to exel rapidly like the downtown core. Then branch outwards with those lines. Why worry about areas that haven't been developed yet like Vaughan. The downtown core is to grow from 250 to 500 thousand in the next twenty years. They should be building more than just one relief line. A good example is to use the Unilever stop as a hub to branch out westward with several subway lines on King ,Queen, Dundas etc. Connecting them to that hub. If they're going to build the downtown area like New York City. They should be preparing for it right now.!!
 
innsertnamehere said:
Queen Street ROW is 20m. A single bore TBM for Toronto is a little over 10m. So you should be fine. It'll have less of an impact when compared to two 6m tunnels beside each other with a buffer.
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The Yonge Line and the PATH connections would make a single bore tunnel quite deep (rock squeeze) - even if the tunnel was mined from Victoria west, it would still need to connect to the existing bore tunnel, no?
 
cd concept said:
I think subways should be built in area where you know the population is going to exel rapidly like the downtown core. Then branch outwards with those lines. Why worry about areas that haven't been developed yet like Vaughan. The downtown core is to grow from 250 to 500 thousand in the next twenty years. They should be building more than just one relief line. A good example is to use the Unilever stop as a hub to branch out westward with several subway lines on King ,Queen, Dundas etc. Connecting them to that hub. If they're going to build the downtown area like New York City. They should be preparing for it right now.!!
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Yes, Downtown Toronto could use at least 3 more subway lines (or 2 U lines). However, there's something we have to deal with: Politics.
 
dowlingm said:
The Yonge Line and the PATH connections would make a single bore tunnel quite deep (rock squeeze) - even if the tunnel was mined from Victoria west, it would still need to connect to the existing bore tunnel, no?
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PATH is very shallow. So is the Yonge Line. Given the proposed depths of the DRL, I doubt PATH would be an issue.

Victoria Line in London actually runs less than a feet under other rapid transit lines. The tolerances are incredible.
 
I don't know, by the time this line gets built, I would have retired, I mean, if I am lucky...
 
innsertnamehere said:
Queen Street ROW is 20m. A single bore TBM for Toronto is a little over 10m. So you should be fine. It'll have less of an impact when compared to two 6m tunnels beside each other with a buffer.
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It was quite the opposite when they did the math for Eglinton. Twin bore had less impact than the single bore option, otherwise it probably would have been a single bore as it was the preferred option in every way except massively increased land expropriation/demolition due to compromised foundations OR significant increase in depth.

IIRC, the general rule seemed to be a tunnel width of buffer on either side. So a 10m tunnel needs, roughly, a 30m corridor. The required buffer, of course, varies significantly by soil type with solid rock needing almost no buffer at all.

A civil engineer familiar with downtown Toronto excavations could wrap up this discussion pretty quickly. When Kyle brought it up I thought he might have some training/experience in the area.


The tunnel design RFP, which closed 5 days ago, for the YRL (Yonge Relief Line) left all options on the table:
https://www.merx4.merx.com/public/solicitations/597794367/abstract
 
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