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They better name the tbm for the OL after the Ford Brothers, and I'm not joking.

Should have called them Jones and Jones.

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Does anyone know why they chose to start north and tunnel south, instead of starting south and tunnel north? (Leaving the TBM stranded at Kennedy doesn’t seem to make sense when it’s known that a TBM will be needed oneday for expansion past Shepard.)

EDIT: Changed old question.
 
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Does anyone know why they chose to start north and tunnel south, instead of starting south and tunnel north? (Leaving the TBM stranded at Kennedy doesn’t seem to make sense when it’s known that a TBM will be needed oneday for expansion past Shepard.)

EDIT: Changed old question.
The TBM will be decommissioned after the tunnel is done, so any northern extension would use a new TBM anyway.

As for the direction, not entirely sure, but my guess is that it might be because Kennedy is currently a construction zone for the Crosstown, so it's easier to build a dedicated TBM launch site at Sheppard/McCowan right now. By the time the TBM gets to Kennedy, the Crosstown will be finished so that conflict won't be an issue anymore.
 
The TBM will be decommissioned after the tunnel is done, so any northern extension would use a new TBM anyway.

As for the direction, not entirely sure, but my guess is that it might be because Kennedy is currently a construction zone for the Crosstown, so it's easier to build a dedicated TBM launch site at Sheppard/McCowan right now. By the time the TBM gets to Kennedy, the Crosstown will be finished so that conflict won't be an issue anymore.
But that’s the thing, since Metrolinx is already digging at Kennedy, why didn’t they make use of the pit to launch the TBM this summer, instead of digging a seperate pit? (And collect the rents from the Ford dealership on top of the Sheppard location for a few more years)

Since they have to dig a big hole at Kennedy anyways for the actual station, might as well get it all done in one go.

I think TBMs are built to last 20 km, to give up on it after only digging 8 km seems like leaving money on the table.
 
I've heard stories years ago that for systems in some cities, they started at the outer end, and dug in, because that way they could guarantee that the project wouldn't be shortened before construction was complete.

I'm not sure if this was a factor for either Scarborough or Ontario - but by starting tunnelling at Sheppard for one, and building the yard at the north end of the line for the other, does make it unlikely that a future government will shorten the line!
 
I've heard stories years ago that for systems in some cities, they started at the outer end, and dug in, because that way they could guarantee that the project wouldn't be shortened before construction was complete.

I'm not sure if this was a factor for either Scarborough or Ontario - but by starting tunnelling at Sheppard for one, and building the yard at the north end of the line for the other, does make it unlikely that a future government will shorten the line!
Wow that does make sense. Lack of political reliability in a democratic system requiring effectively a multi hundred million dollar precommitment mechanisms to make sure the project gets completed.
 
But that’s the thing, since Metrolinx is already digging at Kennedy, why didn’t they make use of the pit to launch the TBM this summer, instead of digging a seperate pit? (And collect the rents from the Ford dealership on top of the Sheppard location for a few more years)

Since they have to dig a big hole at Kennedy anyways for the actual station, might as well get it all done in one go.

I think TBMs are built to last 20 km, to give up on it after only digging 8 km seems like leaving money on the table.


From link.

In December 1990, the French and British TBMs met in the middle and completed the Channel Service Tunnel bore. In all of the tunnels the French TBM was dismantled while the U.K. TBM was turned aside and buried.
The Chunnel TBM's were not sold or reused.
 
But that’s the thing, since Metrolinx is already digging at Kennedy, why didn’t they make use of the pit to launch the TBM this summer, instead of digging a seperate pit? (And collect the rents from the Ford dealership on top of the Sheppard location for a few more years)

Since they have to dig a big hole at Kennedy anyways for the actual station, might as well get it all done in one go.

I think TBMs are built to last 20 km, to give up on it after only digging 8 km seems like leaving money on the table.
Saws, chisels, and other cutting tools do not last forever. They will WEAR out. Some last months, other last for years. Depends upon how much they are used. Use them more, and in more strenuous circumstances, it will be less than a year. Only use them once in a while, it can last years (with lubrication to slow rust). Same with the TBMs. Because of the strenuous work they go under, they can only be used once, even though they are lubricated.
 
I think TBMs are built to last 20 km, to give up on it after only digging 8 km seems like leaving money on the table.
The cost of a TBM is such an infinitesimally small portion of the total budget of this project - or really, any major tunneled transit project - that any perceived value "lost" from its lack-of-use or remaining lifespan is really not worth spending too much time discussing. We really are taking about small fractions of a percentage at this point.

Dan
 
But that’s the thing, since Metrolinx is already digging at Kennedy, why didn’t they make use of the pit to launch the TBM this summer, instead of digging a seperate pit? (And collect the rents from the Ford dealership on top of the Sheppard location for a few more years)

Since they have to dig a big hole at Kennedy anyways for the actual station, might as well get it all done in one go.

I think TBMs are built to last 20 km, to give up on it after only digging 8 km seems like leaving money on the table.
I'm fairly sure the excavations at Kennedy would not have been suitable to just launch the TBM from there, probably not quite in the right place. Also there is the issue of truck traffic to the launch pit to remove the excavated dirt and deliver the tunnel liners.
 
The TBM will be decommissioned after the tunnel is done, so any northern extension would use a new TBM anyway.

I think it would make much more sense to curve west and interline with an extended Sheppard line as I can't really see subways ever being needed either north or east of Sheppard and McCowan.
 
I think it would make much more sense to curve west and interline with an extended Sheppard line as I can't really see subways ever being needed either north or east of Sheppard and McCowan.
isnt it only 1 tbm that is starting from sheppard and mccowan and heading south? ending at kennedy area?
 

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