[BurlOak]

The minimum required tunnel size has been bumped several times and even the first segment has walkways for workers.

It's the job of the fire chief and various others to make things safer and we almost never say no. At some point they're going to inspect the work done on Spadina and give recommendations which will be used for the next line.

Simply put, at this time nobody knows what specs the DRL will be required to have.

If this is the case, it seems very wrong. Safety regulations should be based on canadian standards, which are reflective of international standards. A local fire chief should have no say in this.

 

[gweed123]

If the Liberals are looking to start the Yonge extension before 2016 they had better begin construction of the Downtown Relief Line immediately. The Yonge extension is a no-go without it.

As long as the two are under construction at the same time, I think it should be ok. Yes, it'll be bad for a couple years if the openings don't sync up, but I don't think it'll be the end of the world.

Start the Yonge construction asap, fast-track the DRL, and have overlapping construction for 2-3 years.

 

[gweed123]

Building code is largely based on lessons learned. We may learn that clearances in Spadina still aren't large enough for a train to pass workers on a curve walkway safely. That, I believe, was the main reason why Spadina bores are larger than Sheppards.

The Yonge extension being fairly straight is much more likely to meet new requirements with the existing TBMs.


Worth noting is that there is no obvious reason why the DRL couldn't use Eglinton's TBMs if additional safety buffer space is required. Even if two are put onto Sheppard LRT, all 4 TBMs would be available for the DRL by 2016.

That's an interesting idea, and you're right. There's no reason that the Eglinton TBMs can't be used for the DRL, even if the tunnel would end up being a little bit wider than what is required. I would imagine the extra cost of the slightly wider tunnel would be negligible, especially if it means not having to buy new TBMs. Might even end up being less expensive.

 

[nfitz]

A local fire chief should have no say in this.

I don't think they do. Simply because someone posts something on a Internet forum, doesn't mean it's true!

 

[rbt]

If this is the case, it seems very wrong. Safety regulations should be based on canadian standards, which are reflective of international standards. A local fire chief should have no say in this.

Where do you think the Canadian (Ontario really since provinces make adjustments) standards come from? Professionals who deal with the problems in the infrastructure give their input and adjustments are made to the standards.

The number of subway systems in Ontario numbers roughly 1 which gives the folks in charge of safety in Toronto an unusually high amount of input since they're the only stakeholders in Ontario.


Ontario has numerous requirements for a subway system, from minimum air movement from smoke exhaust systems being higher than other locations (result of Russel Hill) to the requirement that bathrooms be available in the fare-paid area of terminal stations.

 

[innsertnamehere]

be careful, Ottawa is getting a partial subway in 2018, so the number of subways will double.

 

[Platform 27]

The "if only those dumdums would reuse their TBMs we'd have subways everywhere" thread seems doomed to resurface up every nine months like clockwork.

Arguing that 4 previously-used TBMs is of any consequence in getting a $8b subway started is like claiming the old $50 surge-protected power bar gathering dust in my basement closet is going to encourage me to drive to Future Shop and buy a new $8000 home theatre system to plug into it. And that I'd do so knowing this power bar mightn't still work and mightn't fit the same plugs.

They would be suitable for Yonge because it is fairly straight. The DRL will have curves on all axis (X, Y, and Z) which may require a larger bore hole at those curved points than the Spadina TBMs would create; I don't know but it's possible.

I think it's well beyond us in the peanut gallery to start getting into the game of assuming which TBMs are suitable what which potential drives on what potential line. Every TBM is built-to-order for the soil conditions involved. Are you sure the water tables involved in the vicinity of the Yonge Extension's crossing of the Don are suitable for a Spadina-spec TBM? How does the shale content in the ground at Yonge and Steeles compare to the ground at Jane and Steeles? How is the manufacturer's warranty structured for potential use beyond the current project?

Yonge contracts for tunnelling could be tendered very quickly after funding is established as a quick win. It would be pretty slick politically to issue launch point and tunnel RFQ's on the same day that funding is approved.

I think that's wildly optimistic. I could be corrected on this, but I think the Yonge Extension's design and engineering got taken far enough to finish an EA and no further. EAs are rarely any more detailed from an engineering standpoint than 5% design. To tender a construction contract (in the typical process) you're going to want fully-approved 100% design, and between the two lies tens of thousands of hours of man-hours of engineering consultants staring at AutoCAD. Even a P3 design-build RFP doesn't usually go out in Ontario until the design hits 30%. Granted, you can start pre-qualifying contractors a couple of months ahead of the design work actually being ready to hand over, but it's a total misnomer that most projects are "shovel ready" as soon as their EAs are approved.

 

[Transportfan]

Every TBM is built-to-order for the soil conditions involved. Are you sure the water tables involved in the vicinity of the Yonge Extension's crossing of the Don are suitable for a Spadina-spec TBM?

That's a red herring in the case of crossing the Don. They're supposed to replace the current bridge with a high level one and built the subway under the road deck.

 

[BurlOak]

The "if only those dumdums would reuse their TBMs we'd have subways everywhere" thread seems doomed to resurface up every nine months like clockwork.

I think it's well beyond us in the peanut gallery to start getting into the game of assuming which TBMs are suitable what which potential drives on what potential line. Every TBM is built-to-order for the soil conditions involved. Are you sure the water tables involved in the vicinity of the Yonge Extension's crossing of the Don are suitable for a Spadina-spec TBM? How does the shale content in the ground at Yonge and Steeles compare to the ground at Jane and Steeles? How is the manufacturer's warranty structured for potential use beyond the current project?

The only reason to purchase the TBM is if they are planned for re-use. It would have much simpler to have the tunneling Contractor supply the TBM. That way the Contractor is responsible gor everything. The way it is now, if something goes wrong with the TBM the City is responsible to have the TBM repaired - which may be under warranty - but also for any Contractor down time, which could add up very quickly.

 

[nfitz]

Arguing that 4 previously-used TBMs is of any consequence in getting a $8b subway started is like claiming the old $50 surge-protected power bar gathering dust in my basement closet is going to encourage me to drive to Future Shop and buy a new $8000 home theatre system to plug into it.

A most excellent analogy. My hat is off to you sir.

 

[Platform 27]

That's a red herring in the case of crossing the Don. They're supposed to replace the current bridge with a high level one and built the subway under the road deck.

I said "the vicinity" for a reason. While the line will pass over rather than under the river, I'm speculating as a complete layperson there could be water table considerations to take into account for the tunnels immediately before and after the crossing.

I'm not a geotechnical engineer so I don't pretend to say there definitively will or won't be challenges there, or whether the Spadina TBMs definitively are or aren't up to the task. (Ditto for any other part of the project -- the Don crossing was just an example I pulled out of thin air.) My point is none of us really have the credentials or data to start drawing up fantasy 2016 work schedules for Holey, Moley and co.

 

[TJ O'Pootertoot]

The "if only those dumdums would reuse their TBMs we'd have subways everywhere" thread seems doomed to resurface up every nine months like clockwork.

I think that's wildly optimistic. I could be corrected on this, but I think the Yonge Extension's design and engineering got taken far enough to finish an EA and no further. EAs are rarely any more detailed from an engineering standpoint than 5% design. To tender a construction contract (in the typical process)

I stand to be corrected but I believe they subsequently did the conceptual design study which takes them to something like 10%? They're certainly aiming to be "shovel ready" for when funding is announced but there's probably a limit on how literally "shovel ready" they can be without ongoing funding

That's a red herring in the case of crossing the Don. They're supposed to replace the current bridge with a high level one and built the subway under the road deck.

That's mostly right. There will be a new high-level bridge but I think they agreed the subway would run in a tunnel at the bottom of the valley, rather than right under the road deck.

 

[Platform 27]

The only reason to purchase the TBM is if they are planned for re-use. It would have much simpler to have the tunneling Contractor supply the TBM. That way the Contractor is responsible gor everything. The way it is now, if something goes wrong with the TBM the City is responsible to have the TBM repaired - which may be under warranty - but also for any Contractor down time, which could add up very quickly.

Would it be simpler? You've forgotten to include the step where the winning Spadina tunnelling contractor travels back in time to place the order for a customized TBM with a manufacturer two years in the past so they'd have one ready to supply on Day 1.

 

[Transportfan]

I said "the vicinity" for a reason. While the line will pass over rather than under the river, I'm speculating as a complete layperson there could be water table considerations to take into account for the tunnels immediately before and after the crossing.

If the subway line is running above the valley, I can't see why there would be.

But if TJ O' Pootertoot is correct and the plans have changed, you would have a point.

 

[rbt]

Would it be simpler? You've forgotten to include the step where the winning Spadina tunnelling contractor travels back in time to place the order for a customized TBM with a manufacturer two years in the past so they'd have one ready to supply on Day 1.

The cutting head is dependent on soil type and pressure but a head designed for soft soils can handle a large variation in soft soil. They do not change the head every km as you change from a sand/clay mix to a silt/clay mix or other variations.

Worth noting is that Eglinton TBMs were ordered (June, 2010) long before soil sampling was completed (July, 2012? they were still sampling around Allan Road, June 2012 was ongoing at the future Keele Station). TBM price is impacted by the cutting head and sheilds installed.

In Toronto's previous tunnelling exercises we target the sandy/clay segment which covers the city at varying depths. While condos don't sample as deeply as you might want for subway construction, they (the ones I've followed) haven't found anything unusual between Richmond Hill and Finch for soil. It's pretty safe to assume that our "crap-dirt" vein will exist for the Yonge extension but we have not taken soil samples to determine at exactly what depths it exists.

A deep-bore would be a different story and the moraine will make things interesting for Yonge extensions north of Richmond Hill.