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TTC/Metrolinx: Scarborough Subway Extension

Some cookie, some crumble. Toronto had a comprehensive report on the urgency of the problem and the options in 2006. (You know, two years after "Transit First" on the east waterfront...) And a finalized EPR on the chosen replacement only 3 years later. Sometimes you have to just dip the cookie in milk and eat it, not just sit around arguing till it turns into crumbs.
Yep, my point exactly. Maybe the city should make a long-shot case to get construction on the line 2 extension sped up (with provincial funding of course). No way that just 3 stations along 8 km need to take this long to be built.
 
Yep, my point exactly. Maybe the city should make a long-shot case to get construction on the line 2 extension sped up (with provincial funding of course). No way that just 3 stations along 8 km need to take this long to be built.
I agree it could take far less time to build, however I doubt that its even possible to speed it up at this point. Part of the problem is Metrolinx' 2 stage approach to subway building, where we first tender out the contract for the tunneling, and only after the tunneling is almost done do we start building the stations themselves. Every subway project in effect is 2 completely separate projects that are done mostly independently. Now I'm not a project manager, so I'm not going to make an uninformed take about whether or not this method of constructing subways is better, worse, safer, or a waste of time and money, but I think its safe to look at other cities like Sydney or Moscow where both are done at the same time to highlight that a more parallel construction approach would likely speed up construction time. What matters is whether or not Metrolinx believes that the faster timelines are worth it in exchange for whatever risks they feel they're undertaking by parallelizing the work (which considering how Metrolinx seems to be very averse to risk and delays, seems likely to be the driving force behind their decision making).
 
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From the SSE Newsletter:

The TBM has launched and began tunneling from the launch shaft. The TBM has progressed out of the shaft and has advanced under Sheppard Avenue East. The sidewalk on the East side of McCowan Road remains closed. Utility repair work at the northeast corner of McCowan Road and Sheppard Avenue East are complete and the sidewalk/ roadway has reopened to full capacity.

Site preparation continues at the extraction site for the TBM located at the northeast corner of Eglinton Avenue and Midland Avenue. The first stage of piling works has been completed. Works are no focused on preparations for the upcoming pedestrian and vehicle detour on Eglinton Avenue East to prepare the TBM extraction site.
 
One would think that if the TBM were not progressing as per schedule, there would be an inventory of tunnel liners piling up somewhere..... has anyone seen evidence of this?

- Paul
 
One would think that if the TBM were not progressing as per schedule, there would be an inventory of tunnel liners piling up somewhere..... has anyone seen evidence of this?

- Paul
There would be an inventory of tunnel liners no matter what - they are not shipped just-in-time, but rather as they are made. They are stored on site as there can be peaks and troughs in the production flow, and the last thing anyone wants is to hold up the TBM because there isn't enough liners to fit.

If the TBM wasn't progressing to schedule, what there would be a lack of, however, is spoil.

One other thing to consider is that TBMs are not turned on to 100% immediately upon starting. The first several weeks or months of the drive will be done more slowly, as they break in the various components and test the different systems. Only once they are confident with it will they then begin operating at the full production rate. That's why that "15m/day" number that gets thrown about frequently is also cited as an average - once things are up and running smoothly, it is possible to double the production of that average number.

Dan
 
There would be an inventory of tunnel liners no matter what - they are not shipped just-in-time, but rather as they are made. They are stored on site as there can be peaks and troughs in the production flow, and the last thing anyone wants is to hold up the TBM because there isn't enough liners to fit.

If the TBM wasn't progressing to schedule, what there would be a lack of, however, is spoil.

One other thing to consider is that TBMs are not turned on to 100% immediately upon starting. The first several weeks or months of the drive will be done more slowly, as they break in the various components and test the different systems. Only once they are confident with it will they then begin operating at the full production rate. That's why that "15m/day" number that gets thrown about frequently is also cited as an average - once things are up and running smoothly, it is possible to double the production of that average number.

Dan
Right, but assuming they've only dug 100m so far, the average comes to about 40cm per day, quite far from "15m/day". Surely something's up.
 
Right, but assuming they've only dug 100m so far, the average comes to about 40cm per day, quite far from "15m/day". Surely something's up.
It's tough to judge, but the distance in the photos attached above looks to be far more than 100m to me. The machine itself is longer than that distance, and so even if it's only doubled its own length, that means they've tunneled more than a quarter kilometer thus far.

But again, you don't just turn it on and start at 15m/day. And especially with a much larger machine like this one, it may just take longer to get it up to speed.

Dan
 
Does it really matter if the tunnel is a little behind? The tunnel on eglinton was completed ages ago. My understanding is that it’s the stations which take longer. How are they coming along on the new stations?
 

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