afransen
Senior Member
Toronto subways were expensive before that! The lumber market is tight because of COVID reducing supply and increasing demand (nesting=decks+sheds).
- Thread starter 299 bloor call control.
- Start date
aquateam
Active Member
I think there are some clear advantages to cut and cover that deserve more than a boilerplate "it's disruptive" response. After all, it's not as though using traditional TBM construction on Eglinton hasn't been disruptive. The cost savings of C&C are well-established:
- During construction of the Canada Line, according to court documents SNC-Lavalin was able to save $400 million out of a $2.1 billion project cost (?!) and get back on schedule by C&C'ing a third of Cambie
- The European Commission estimates that C&C is "three times cheaper" (1/3rd the cost) than boring
- Another case study found a 60% reduction in costs using C&C
This construction method isn't appropriate for everywhere: narrow streets lined with tall buildings on shifting foundations, for instance, would not do well with this method (although Milan was able to find ways around that.) And if you are going under other subway lines, very deep into bedrock, boring is the only answer. But this section of Yonge is very wide, with generous setbacks, and we are not going under any other subway line. it is very unlikely that there is a geological reason precluding C&C. In fact, C&C is how Line 1 was extended to its current terminus (for < $100 million/km in 2019 dollars.)
The difference is that unlike other methods of value engineering, C&C improves the final product. Station access times are shorter, there is better connectivity to surface routes. Maintenance and ventilation is a lot easier. All because you are building a 2 story underground building instead of a 7 story underground building.
Given how intensely Metrolinx has been (inconsistently) value-engineering their lines (cutting out bus terminals, stations, wonky alignments), it's unfortunate that outside-the-box thinking doesn't extend to delivering projects in a non-traditional way.
Lets say C&C saves $1 billion (not an unreasonable amount) and allows for the neighbourhood stations to be added back in at the same budget. Would people in the neighbourhood be willing to accept short-term construction pain for the permanent benefit of a station? Maybe not, but without Metrolinx even putting it on the table we wouldn't know.
Elevated is also a good alternative, it's how Vancouver has been able to extend its Skytrain network to be the longest rapid transit system in Canada despite starting 30 years after Toronto. But if Thornhill's Heritage Conservation District is concerned about the lighting of their Tim Horton's drive throughs, then I'm sure they would be apoplectic to have TRs running on guideways through Yonge.
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afransen
Senior Member
If the Heritage District is that precious, it's obvious it could not withstand the development pressure a subway station would create. So, it's pretty clear then that there should be no station there.
Frankly, I think we should be more pragmatic about heritage. Is the risk of damage to the heritage character of that area really in excess of a billion dollars? Is there no price to be put on marginal heritage areas?
TJ O'Pootertoot
Senior Member
Right. And there isn't one. So, everyone is happy.
I mentioned it above, in reference to a potential elevated track. But there isn't one of those either.
Anyway, we dealt with this heritage issue a few pages back. Some of us value it, some think that 150-year-old houses aren't worth very much. It's established.
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afransen
Senior Member
It has a value. I just don't think it would be diminished by the equivalent of a billion dollars. Here's a map.
Surfacing with a portal at the south bank of the Don would have essentially no impact on the Heritage District. If the portal is on the west side of Yonge it is not even in the district! North of this point is essentially strip malls. You would not be able to see the above-ground portion of the extension from any of the individually protected properties in the district.
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W. K. Lis
Superstar
If they use the tunnel boring machine (TBM) deep between stations, but raise it closer to the surface near the stations (and making sure the stations are off to the side), they can be less of a problem. Raising the stations closer to the surface would reduce the cost to dig down for the station box, and will let gravity help to slow the trains entering the stations and accelerate leaving the stations.
An example of such could be the Moss Park Station on the "Ontario" Line. From link.
An example of such could be the Moss Park Station on the "Ontario" Line. From link.
TJ O'Pootertoot
Senior Member
Yes, if you surfaced in the valley you'd be clear of any heritage issues. It's worth mentioning, the initial plan involved briefly popping outdoors here on the north side, crossing on a bridge over the valley, before going back under before Royal Orchard. Would have saved some deep tunnelling under the river and I kinda wish they'd kept that but I suspect the turn made it too hard.
I dunno how the rest of it works but, as I said, people should ask Metrolinx some details at the meeting to shake them out of the "um, it's disruptive" rote response.
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syn
Senior Member
But there are NIMBY types along the rest of the line - which is why, just like Sheppard, most of the line is probably not going to see a lot of development.
Should it pop up and run through a heritage district? Perhaps it should utilize the existing rail corridor much earlier.
The area you're referring to for density is surrounded by a lot of large subdivisions. It isn't terribly large, and I can't help but question what kind of density we'll see there, and it's form. Will it be walkable and pedestrian friendly? How many office towers? How many condo towers? It's going to have to be significant.
In any case, I have to echo what @44 North mentioned earlier:
aquateam
Active Member
If they use the tunnel boring machine (TBM) deep between stations, but raise it closer to the surface near the stations (and making sure the stations are off to the side), they can be less of a problem. Raising the stations closer to the surface would reduce the cost to dig down for the station box, and will let gravity help to slow the trains entering the stations and accelerate leaving the stations.
An example of such could be the Moss Park Station on the "Ontario" Line. From link.
I don't think you can really get shallow stations once you've decided to go with a TBM. That section of the Ontario line is going diagonally under foundations and utilities (including a storm sewer), so there is limited opportunity for it to rise up.
For geotechnical reasons I believe you also need to stay in the bedrock.
Here is the Relief Line Moss Park station drawing: it shows the floor of the station ~25 meters below ground.
Raising the elevation of the tracks at the stations to let gravity do work is smart, I've heard the Montreal Metro does that. But it's not going to make a significant impact on the depth of the stations.
TJ O'Pootertoot
Senior Member
These two things don't necessarily add up. Yes, there will be some NIMBYs but most people know the development is coming. I'm not really worried it won't happen. The Markham plans aren't finalized but have been in progress for years and the Vaughan Secondary Plan was approved 10 years ago; people know the deal.
The first few developments, proposed for Yonge/Steeles, have drawn attention but understandably as they're huge and the subway is still a decade away. But I have zero concerns the density will materialize. Time will tell.
I'm not sure which area you're talking about specifically. Starting at the south end:
-Yonge/Steeles is already seeing mega-proposals (multiple towers, 50-60 storeys) that will extend pretty much all the way to Hilda Ave along Steeles and the car dealerships and strip malls will soon be gone, and the people know that. As I said above, the first few developments are already in excess of what was approved in Vaughan's SP for the area, and I agree that the sheer scale of what they're asking is excessive and residents are right to point it out. But I wouldn't say they're being NIMBY's. It'll mostly be condos, no question, but there will be some office and retail mixed in.
-Yonge/Clark only has subdivision on the east side of Yonge, really. You can see, pretty clearly, where the intensification there will happen. Probably it'll go up to Elgin, where the Farmer's Market is.
-Then there will be a break for the heritage district and the valley. The rest depends a bit on what happens with Royal Orchard. It's a wild card because who knows what will happen with that large site at Royal Orchard if there is no station... but let's assume there is one. Residents know that's gonna be a package deal: subway station + mega development on that site. Then there are strip malls to the north and you're right; they're relatively shallow lots until you get closer to 407 and there will be some pushback, perhaps but again: Markham knows the trade-off they're agreeing to if that station goes in.
I guess I should add a map, to have handy here. (I just made little Xs for the stations).
And, more to the point, this line has something Sheppard doesn't: a couple of hundred of blank-slate acres at the end of the line, ready and waiting for highrise development, wall to wall. That's where most of the development will go, including the vast majority of any employment uses, and that's the pot of gold at the end of the rainbow, the larger corridor will have a decent amount to supplement that. There are some neigbhourhoods north and west of the of the growth centre but they also know what's coming. All the NIMBYs in the world won't put it a dent in it. The Provincial policy is set in stone so even if council, which has supported density there, gets cold feet, the LPAT will shoot them down every time.
Anyway, you can question it but I'd have a look at what is going on north of 7, on either side of 16th. Particularly on the south side of 16th, where there are subdivisions set back not too far from Yonge.
I blocked that dude many moons ago and can't see his posts but I'm sure he has nothing to say I'd find interesting.
Attachments
allengeorge
Senior Member
Oh - I absolutely agree that there are significant benefits to cut-and-cover. I still maintain that one only has to look at the electoral map to figure out why Metrolinx where chooses to use TBM.
44 North
Senior Member
Oh was that when I called you out for manically spamming the board with lies lol
44 North
Senior Member
That's what people said in the 00s. Seems like half the Langstaff site was greenlit for development over ten years ago with or w/out a subway. Nothing's been built. Also appears ridership modeling fell by like 75% for the extension, and that's with an added decade for the projection (2040). Def lots of riders coming from between Finch and Steeles tho which is why dropping Drewry is questionable.
Def huge merit to cut/cover. But if it's not happening on Eg West seems safe to say it's not happening anywhere. That's like A1 for most optimal conditions. Literal vacant transportation corridor set aside for transportation use, but the team at QP decided screw it let's TBM adjacent to it. I would like to see these TBM depths for YNSE tho. It may be extreme.
Leo_Chan
Senior Member
How about realigning Highway 407 south to next to the cemetery so that development can occur on both sides of Highway 7?
ARG1
Senior Member
That would be very expensive for no real benefit.