[nfitz]

I'm no engineer or anything but could there be any conceivable benefit to switching away from TBM at this point?

Well, it might save them from digging a rescue shaft to recover it.

Though to be serious, I don't really see how that works - they've gone too far down this path already. I'd be less surprised if they cancelled it (though that would still surprise me too!).

 

[TOtramz]

Well, it might save them from digging a rescue shaft to recover it.

Though to be serious, I don't really see how that works - they've gone too far down this path already. I'd be less surprised if they cancelled it (though that would still surprise me too!).

Honestly, I'm surprised it's taking almost a year to get the TBM moving along again. I mean all they would have to do is dig a hole and swap out the cutting face and it's on its merry way right?

Maybe add some booster rockets on the back end

 

[kev1n1m]

Isn't it under the 401 though?

 

[TOtramz]

Isn't it under the 401 though?

I heard somewhere that they managed to push it south of the 401. Actually when I’m driving along the 401 near mccowan I see crews digging something on near the south east interchange ramp. I wonder if the TBM is near there.

 

[crs1026]

I mean all they would have to do is dig a hole and swap out the cutting face and it's on its merry way right?

Well, if things are bent, or bearings are damaged, or if seals have given out... the repair needed may be in a much more awkward location than the cutting face. The "intervention shaft" may be basically a whole new insertion/removal shaft.

- Paul

 

[TOtramz]

I have a question about how much info we can glean from the launch site near Mccowan and Sheppard.

I pass by the site a couple times a day, and I notice that there is a rope gate in the morning but no gate at night, so I think the site is still active. For a period of time I also saw the main crane dropping blue metal scaffolding into place, wonder what that’s for. I also occasionally see trucks moving in and out of the site.

Assuming the TBM moved back online, I guess we would see much more trucks moving in and out?

 

[NIV]

I also drive by McCowan and Sheppard quite often, I’m looking forward to seeing the elaborate conveyor system for dirt removal working at close to capacity. Hopefully they are able to fix the TBM to make this happen. Unfortunately this single bore TBM is the only option now, system design and contracts for tunnel rings and other components have already been committed to.

 

[crs1026]

I have a question about how much info we can glean from the launch site near Mccowan and Sheppard.

I pass by the site a couple times a day, and I notice that there is a rope gate in the morning but no gate at night, so I think the site is still active. For a period of time I also saw the main crane dropping blue metal scaffolding into place, wonder what that’s for. I also occasionally see trucks moving in and out of the site.

Assuming the TBM moved back online, I guess we would see much more trucks moving in and out?

The most significant things we would see during an operating tbm drive would be
- dump trucks hauling away dirt
- delivery of tunnel sections (one wonders if that contract was paused, or are the liner sections being manufactured and are piling up in storage somewhere ?)
- delivery of conveyor belt, airway tubing, lighting etc to be gradually installed as the tunnel lengthens (ditto?)
- food trucks !

- Paul

 

[smallspy]

I heard somewhere that they managed to push it south of the 401. Actually when I’m driving along the 401 near mccowan I see crews digging something on near the south east interchange ramp. I wonder if the TBM is near there.

The cutterface and main drive are immediately south of the 401.

The trailing portion of the device, however, is still under the 401. The whole device is well over 100 metres long.

Dan

 

[TOtramz]

The cutterface and main drive are immediately south of the 401.

The trailing portion of the device, however, is still under the 401. The whole device is well over 100 metres long.

Dan

Would they be able to access by digging down on mccowan or would they have to mess with 401 lanes as well?

 

[Northern Light]

I'm no engineer or anything but could there be any conceivable benefit to switching away from TBM at this point?

There are engineers here, I am not one.

However, I feel confident in saying that 'no' you can't really make that switch beneficially or easily.

The routing would vary slightly, likely requiring further property acquisition.

But setting that to one side, the depths would be different. So you'd have to get the tunnel up to cut and cover depth, you'd also have to design that. Then there's the small matter of the stations which have all been designed for trains at deep bore depth.

I'm not sure how far along any stations sites are, but comprehensive re-design would add at least 2 years to the project time frame, probably longer.

If construction is at all advanced on any of the stations, there would be demolition and reconstruction to allow for the new depths likely removing a concourse level. It would be a very big deal.

Re-design also costs money, and lots of it.

 

[smallspy]

Would they be able to access by digging down on mccowan or would they have to mess with 401 lanes as well?

It depends on what they're trying to do.

It seems that the fault that stopped the TBM was in the cutterhead or drive, so they only need enough of a pit to access those components. This is the same situation with Seattle's Big Bertha - despite the TBM being even bigger than this one, they only needed to excavate a pit about 20 metres square.

If you need to repair other parts of the TBM, in most cases they can do so from inside. It's really just the drive, cutterheads and drive bearing that can't. And if they wanted to extricate the whole thing, they could so so in sections by driving it into a pit and pulling the section out - opposite the way it was built

Dan

 

[generalcanada]

It depends on what they're trying to do.

It seems that the fault that stopped the TBM was in the cutterhead or drive, so they only need enough of a pit to access those components. This is the same situation with Seattle's Big Bertha - despite the TBM being even bigger than this one, they only needed to excavate a pit about 20 metres square.

If you need to repair other parts of the TBM, in most cases they can do so from inside. It's really just the drive, cutterheads and drive bearing that can't. And if they wanted to extricate the whole thing, they could so so in sections by driving it into a pit and pulling the section out - opposite the way it was built

Dan

Oh interesting, reading up on that, it seems like replacing the blades seemed to have taken about 2 months.
the main bearings failed later on due to overheating which added a year delay due to them needed to extract the whole cutterhead.

Even if we assume everything was going well until mid 2023, thats still 1.5 of delays with nothing to show for it.

 

[NIV]

Having the intervention shaft right at the side of the 401 and the entire length of the TBM under the 401, to me is an indicator that something more serious is wrong. The intervention shaft is at an awkward small location between the 401 and the on ramp, I’m guessing they will have to shut down the eastbound ramp if they need to bring in big equipment once they’ve excavated the shaft. Tough place to pick to only be doing maintenance as metrolinx would have us believe.

 

[TOtramz]

Having the intervention shaft right at the side of the 401 and the entire length of the TBM under the 401, to me is an indicator that something more serious is wrong. The intervention shaft is at an awkward small location between the 401 and the on ramp, I’m guessing they will have to shut down the eastbound ramp if they need to bring in big equipment once they’ve excavated the shaft. Tough place to pick to only be doing maintenance as metrolinx would have us believe.

When I look at that little corner near the 401 ramp, it doesn't seem like they dug much. All I see is a small mobile crane and some trucks. I recall seeing the crews there for a while now, at least 6 months ago, which leads me to wonder what they have been doing at the site all this time.