chrisw
Active Member
@reinventingthewheel Ehhh, that sounds like you're giving Metrolinx a pass. I'd think it'd be Metrolinx choosing to keep tight lipped.
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Aplus23
Active Member
Are they even going to start station construction before the tunnel is completed
NIV
New Member
With the TBM stuck under the 401 the province needs to step in and reevaluate the feasibility of this project as presently designed. Obviously we are going to be drastically over budget and many years behind schedule if we continue to forge through with this deep single bore TBM. Hopefully the media and opposition parties start asking questions. Let’s learn our lesson from the crosstown fiasco.
Allandale25
Senior Member
nfitz
Superstar
They wouldn't need to rebore everything. But they would need to redesign stuff. Order one or two new bespoke TBMs. Significantly modify the launch and recovery sites.
They've tunnelled about 1 km so far, in 2 years. There's still over 6 km to go.
But it seems unlikely that even at this point, it would be faster (or cheaper) to switch to dual bore tunnelling.
Kyle Campbell
Senior Member
They could switch to SEM to keep it as a single bore tunnel, if they really needed to
NIV
New Member
They are about 1km of the 8km’s. Could they transition to a dual bore at this stage? Not sure. The single bore made sense when it was a one stop subway, the 3 stop subway inherited the existing design. Never made sense with 3 stops, way too deep!
nfitz
Superstar
Not through the soils that they originally envision. There's probably 40-metres of head at certain locations!
Indeed. Lawrence East station in particular is completely absurd. With the earlier (3-station TTC) design, Lawrence West would have been a lot like Don Mills station. Very shallow with a bridge over Highland Creek just north of the station. Now it's 40 metres deep there. It was always expected to be the difficult spot with this final design - and very expensive now.
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TOtramz
Active Member
micheal_can
Senior Member
Have we even heard of why there is a problem? Without knowing that, even a twin bore may not be the solution.
PL1
Senior Member
Officially no. But the scuttlebutt (including from an engineer friend at the City) is soil conditions.
NIV
New Member
Would a strategic 2-3 year tunneling redesign delay be better then continuing with the current TBM and its delay and increased costs.
micheal_can
Senior Member
dullturtle06
Active Member
Yes i agree, if they soil conditions under the 401 are an issue, i can only imagen what the soil conditions under highland creek are. They should twin bore north to the 401 and bridge over the creek. But i think Metrolinx is allergic to accountability and flexibility.
TOtramz
Active Member
The TBM is already south of the 401, so that would not be needed.
Though I seriously doubt you could cut and cover to the depths that the current tunnel is already at, or perhaps they could do a gradual ramp up?
I have also noticed that all the equipment from the 401 intervention site has been removed, all that is left is some giant concrete blocks. This combined with the increasingly high stacks of tunnel liners at the launch site leads me to believe they might be starting up soon.