TOtramz
Active Member
The little patch of dirt near the 401 ramps was apparently the site of digging down to repair the TBM cutting head, yet from aerial photos you wouldn't be able to tell that much was done there.
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nfitz
Superstar
crs1026
Superstar
Let's see what is said at the next Metrolinx Board Meeting.
It's a shame that we UT'ers didn't get out and drone this thing sooner, but maybe there wasn't a lot to see. We imagined the machine needing some major component replacement that would demand a huge shaft, but maybe the obstruction or failure was a lot smaller and only needed minimal access.
In some ways it's good to see that the site has been completely backfilled already. But the silence about the cost and schedule impact is not acceptable.
- Paul
nfitz
Superstar
I suspect after they've kept the lid on this since 2023, that they'll suddenly become communicative about it now. The only time anything was said at all, was by Verster after he'd already decided to quit. And even then, it was just a whisper.
NIV
New Member
I believe they can’t start digging out the station box until the tunnel is complete. The earth around the tunnel segments keeps the tunnel intact and allows them to move forward. They could probably start other sections of the stations that don’t involve the tunnel.
TOtramz
Active Member
If true, I think it's even more damning that a small repair would derail tunnelling for so many years...
crs1026
Superstar
Well. "small" in size may not be such in timeline impact if, for instance, custom parts had to be procured.
I would think any event that stalled the machine would demand a certain amount of delay - to verify the location of the machine, confirm (without ability to inspect directly, perhaps) what the problem is, leading to enough confidence to design an "intervention shaft", and then execute same.
From the boring that went on directly on the 401, there may have been exploration and then forcing the machine far enough south to reach a diggable spot.
The resolution might actually merit some recognition for the technical people who solved it..... if admitting problems wasn't such a big non starter.
- Paul
TOtramz
Active Member
I imagine that is probably true for Scarborough centre, but apparently there are techniques to stabilize the earth around a station box if you started digging it before the TBM passes through. A prime example would be the western stations on the ontario line.
The more important questions is whether they can start excavating lawrence east station, beyond the 4 pits they already have.
Of course with so much secrecy, nobody knows anything for certain.
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TOtramz
Active Member
I think you forgot to attach the images....
Aplus23
Active Member
Work going on in the parking lot of the Don Montgomery community center, this has to do something with the Danforth extension, They said this will be ongoing for years. Pretty sure the tunnel is under there
nfitz
Superstar
Yes, that's where the tunnel tail tracks are. As they are lowering the elevation of the structure, and then building new tail tracks on top of the new tunnel, that's going to be a very big hole.
I'm not sure where the TBM recovery hole is. That part will be open for years.
Aplus23
Active Member
Huh, so there will be two sets on tunnels under there, a lower tunnel and then a tunnel on-top??
What will the lower tunnel be used for ?
nfitz
Superstar
Yes. The lower tunnel is the subway line to Scarborough Centre. The upper tunnel (it's one big structure really) is the new dead-end tail tracks.
Unless they've re-engineered it since the last drawing set I saw.
JBR
Active Member
Huh? So there will be a crossover east of Kennedy going up to storage tracks? Or will it be a centre track like Chester/Christie?
nfitz
Superstar
I don't remember any more. A single storage track would be simplest.
Looking at the Environmental Project Report amendment from 2020, from the (confusing) figures, it looks like a single track. But the text uses the plural "pocket tracks". I recall though that they were still trying to finalize this in 2021, including making sure there was space on the north side for the (now cancelled) Eglinton East tunnel.