[Edward]

Thanks for the pictures. With all the talk about Scarborough, Smart Track and cost overruns on Spadina I think many people forget a major line is currently under construction across the middle of Toronto.

 

[Conrad Black]

Exciting times.

 

[DonValleyRainbow]

Okay, is it just me or are TBMs supposed to be longer? Behind the cutterhead, I thought it was a whole assembly line of drilling and liner fitting equipment. Was this moved in smaller pieces?

 

[valvenis]

It may be a silly question, but why didn't they tunnel under the Spadina Subway? Don't they have to eventually do that anyways?

 

[JayBeeGooner]

Risk of the subway tunnel shifting.

 

[valvenis]

Risk of the subway tunnel shifting.

Ok, so the problem will still have to be addressed on the future.

 

[JayBeeGooner]

Ok, so the problem will still have to be addressed on the future.

I'm not sure if it's a problem. I'm not an engineer, but it doesn't seem too big of an issue to shore up the tunnel with steel beams and excavate while the subway is running.

 

[AlvinofDiaspar]

I'm not sure if it's a problem. I'm not an engineer, but it doesn't seem too big of an issue to shore the tunnel with steel beams and excavated while the subway is running.

Yep, it's been done elsewhere before.

AoD

 

[nfitz]

Ok, so the problem will still have to be addressed on the future.

It would have to be addressed in the future anyways. If you'd have kept tunnelling under the existing station, you'd still have had to have dug down to build the platforms and remove all the tunnel segments. And you'd have had to have been deeper under the existing track than if you did it the way they are planning.

 

[TheTigerMaster]

Okay, is it just me or are TBMs supposed to be longer? Behind the cutterhead, I thought it was a whole assembly line of drilling and liner fitting equipment. Was this moved in smaller pieces?

The TBMs are way longer than in the photographs. All we're seeing is the cutter head.

 

[Edward Skira]

Sorry I missed this. Looked like fun.

 

[CDL.TO]

I wonder how this approach compares to the "drag through" approach I've seen used elsewhere. That's where they excavate the station box first and drag the TBM through it.

[video=youtube;EcF1MKfGreU]https://www.youtube.com/watch?v=EcF1MKfGreU[/video]

 

[Voltz]

I wonder how this approach compares to the "drag through" approach I've seen used elsewhere. That's where they excavate the station box first and drag the TBM through it.

I was wondering why they did not try something like this.

 

[JayBeeGooner]

I was wondering why they did not try something like this.

Because TBMs are usually "dragged" through a station box to continue tunneling. Since the station box for the station wasn't built yet, it made more sense to lift the TBMs over the existing subway and continue tunneling to Yonge. If the TTC was building the ECLRT, it's likely the station would have been built, but Metrolinx wants the stations to be built at the same time.

 

[howl]

Ok, so the problem will still have to be addressed on the future.

They plan on tunneling under the both subway lines (Spadina and Yonge) using a much less intrusive method.

Regarding the timing of building the stations and tunnels, obviously you can't build them at the same time. You have to build one first then the other. One of the biggest hold ups for the station construction is they need to acquire all the land. If an owner doesn't want to sell they need to expropriate and it can take up to a year to go through that legal process. If they wanted to build the stations first we would still be waiting to start tunneling. starting the tunneling first means they will be done sooner.