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Assuming that the TBM is under repair near the Freshco work site, it would be so cool if we had some high-vantage footage of the work being done on the cutting face 🥹
 
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Station construction at Lawrence and McCowan.
 
Here's a photo of the SkyTrain Evergreen Line Extension tunnel boring machine. Sources differ, but its diameter was somewhere in the neighbourhood of 9.8- to 10-metres. Regardless, it gives a sense of scale to these remarkable machines and puts the 10.7-metre diameter TBM for the Scarborough Subway Extension into perspective..

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Source
 
Just to be correct. The Scarborough TBM is not 10.7m. It is around 12m.

The tunnel that will be built has an internal diameter of 10.7m.
I'm sure it was mentioned somewhere way back, but why did they end up choosing single bore for this? It seemed for a while twin bore was the default for projects, but it seems single bore is back in vogue. I'm curious as to the reasoning
 
Lots of action at STC in the past few weeks.

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Assuming that the TBM is under repair near the Freshco work site, it would be so cool if we had some high-vantage footage of the work being done on the cutting face 🥹
They recently removed the equipment from the site and it's now sitting idle. Took a peek through the fence but didn't spot a pit.
 
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I'm sure it was mentioned somewhere way back, but why did they end up choosing single bore for this? It seemed for a while twin bore was the default for projects, but it seems single bore is back in vogue. I'm curious as to the reasoning
A single bore can speed up the project significantly if it worked out. The whole station box won't have to be excavated, instead the platforms would be built in the tunnel on two different levels. They just need to dig a few shafts for the stairs, elevators, ventilations and utilities. This would reduce the whole building footprint.

With a twin bore, they would have to either dig the entire station box to fit the platform in between and cover it back up. Alternatively they can use SEM (like OL and a couple line 5 stations) but that still requires digging a shaft first to bring the equipment to track level before cutting the tunnel liners to dig a cavern. Both requires a year or two of excavation before they can even start on the station structure.
 
Lots of action at STC in the past few weeks.

View attachment 668438


They recently removed the equipment from the site and it's now sitting idle. Took a peek through the fence but didn't spot a pit.
https://assets.metrolinx.com/image/...x/SCS_Traffic_Stage_2A_and_SOE_Notice_Eng.pdf
Looks like they are doing piling work to support future excavation
But it's still an open question if they can begin excavation before the TBM has reached the destination......
 

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