[Leo_Chan]

I'm no engineer, but I doubt that is true.

- Twice the depth means that the tunnel has to support twice as much dirt above it. That means more concrete and building materials to support the weight

- The deeper the tunnel, the harder it is for air to reach those depths. That means bigger, more expensive tunnel ventilation systems, to get air to these depths. These systems make up a non-negligible cost of subway construction. In comparison, Toronto's older subways are shallow enough that they can naturally ventilate, without specialized machinery.

- Deep tunnels increase the costs of emergency exits

- Temperaure control might be a concern so far underground. I recall that when the Russell Hill accident happened, the tunnel was dangerously hot for first responders, not because of fire, but because the tunnel trapped heat. Average tunnel temperatures increase significantly as depth increases, however the difference between seasonal absolute highest and absolute lowest temperatures decrease. Depending on exact conditions, tunnels 20 feet deep might require temperature control, so people down there don't fall ill due to high temperatures.

Walk up the emergency exits would be a pain from 20m underground. Being deep underground does raise ambient temperatures, but we're not talking about kilometres underground, on less than 50m, so it's not the natural temperature, but artificial heat produced by electronics, trains, heater, and humans that is trapped underground. This is why subways have large emergency fans that help ventilate in emergencies. See the TYSSE thread for some pictures/videos. I'm sure the engineers and planners have taken into consideration the depth of the SSE, safety is more important than costs to the TTC.

 

[crs1026]

Yeah, there were a few utilities in the way for the Yonge line. Probably fewer on an arterial road in Scarborough. I wonder whether some of that infrastructure is nearing end of life anyways....they will have been built in the 1950-65 era. In other parts of the City that were built around the same time I see lots of replacement work. Those streets may get dug up in places anyways. Maybe cut and cover would be an opportunity to renew it all at the same time.

- Paul

 

[44 North]

I'm no engineer, but I doubt that is true.

- Twice the depth means that the tunnel has to support twice as much dirt above it. That means more concrete and building materials to support the weight

- The deeper the tunnel, the harder it is for air to reach those depths. That means bigger, more expensive tunnel ventilation systems, to get air to these depths. These systems make up a non-negligible cost of subway construction. In comparison, Toronto's older subways are shallow enough that they can naturally ventilate, without specialized machinery.

- Deep tunnels increase the costs of emergency exits

- Temperaure control might be a concern so far underground. I recall that when the Russell Hill accident happened, the tunnel was dangerously hot for first responders, not because of fire, but because the tunnel trapped heat. Average tunnel temperatures increase significantly as depth increases, however the difference between seasonal absolute highest and absolute lowest temperatures decrease. Depending on exact conditions, tunnels 20 metres deep might require temperature control, so people down there don't fall ill due to high temperatures.

Tunnelling deep does have benefit in the area south of Bloor-Danforth. This is really the only place where we can optimally take advantage of using bedrock to tunnel through. Basically all of TO has a very high water table, and the porous sand/till below the surface makes any kind of subsurface infrastructure project a hard task in this city (dewatering, pumping, diversions, sinkholes, etc). However where the bedrock is closer to the surface (south of Bloor area), we can use rock's general impermeability. It's not 100% optimal, since our shale bedrock is flaky, fractured closer to the surface, and expands when exposed to air. But it's still a lot better than tunneling through waterlogged sand/gravel found everywhere else, and where bedrock would be way to deep to use.

 

[amnesiajune]

Gone are the days when Toronto had the balls to cut-and-cover it's busiest transportation corridor (Yonge St) and leave it an open pit for five years in the heart of downtown.

That was post-WW2, when (A) people really didn't care because they saw how much worse the rest of the world was, (B) the whole city was under construction anyways, and (C) bored tunnels were prohibitively expensive. And the only street that was torn up to build a subway was Yonge Street, south of College and north of Sheppard. The rest of the subway system (aside from stations) was built away from roads or using TBMs.

Anyways, it's not noise-related. There are much better ways to reduce noise and vibrations nowadays than just increasing tunnel depth. It's probably needing to avoid utilities (of which there were a lot fewer downtown - remember that the Yonge subway predates things like cable TV and separated stormwater & wastewater sewage), easier digging at certain depths due to soil composition, or some combination of the two.

 

[Edward Skira]

Yonge subway tunnel between Collage and Wellesley. How many metres deep is this? 3m?

http://urbantoronto.ca/forum/thread...rchitectsalliance.16369/page-128#post-1184703

 

[Adjei]

https://www.thestar.com/opinion/letters_to_the_editors/2017/01/23/scarborough-choke-point.html

From the Stars hate mail bag.

Surely if a parking lot is required to be expanded they can build another level somewhere. Such an empty rant. But he did say boondoggle which met the main criteria to publish

Furthermore his concern sounds more like he thinks it will be a great success bringing in some new commuters of the 401.

Hello coffey..

 

[pstogios]

Hello coffey..

A few weeks ago he admitted he is the same guy.

He also said he wouldn't engage in personal attacks.

But he never said he would stop the paranoia and conspiracy theory.

 

[44 North]

A few weeks ago he admitted he is the same guy.

He also said he wouldn't engage in personal attacks.

Exactly, he admitted his previous ID. And said he doesn't want to engage in attacks. So I don't see the need for people to act like they discovered it's a new account, or pounce on him with their own personal attacks. And really, many of the points he makes aren't all that unique to him or this project.

 

[Forgotten]

I found this alignment on a TTC presentation, but I couldn't find the analysis of routes on why this did not make the short list.

My guess would be that the short list found that the McCowan route is preferred because it hits nodes at Brimley, Lawrence, STC and Sheppard.
The other one to make the short list was Midland, so the STC station could be in the middle of STC.
The final one was along the SRT corridor.

When the short list was being analysed, they realized they had to cut money, so they stripped the stations to save money - even though without intermediate stations they may have screened out a preferred solution.

Does one really need to ask? I'll give you a hint: it starts with Scam and ends with Track. McCowan was selected over SRT or Brimley corridor so it wouldn't steal ScamTrack's thunder. Similarly happened with the selection process for the relief subway. ScamTrack is like anti-gravity. Both subways get pushed away from where they otherwise should be because we're told it makes no sense to put them where they should be because something something ScamTrack is going to be a surface subway with subway like frequencies. How's that working out?

The city had an allegedly objective ranking process but in both cases the lesser of options magically get chosen. Why waste so much taxpayer time and money with the traveling road show presenting all of those fancy pie charts and score cards trying to pull the wool over everybody's eyes when the points don't matter in the end?

Obviously there was a quid pro quo of sorts. John must have promised Jennifer his backing on her own pet projects (her unfunded and legally untested rail deck park, her ill placed transit mall) on the condition she supported his signature re-election project.

 

[Rainforest]

Does one really need to ask? I'll give you a hint: it starts with Scam and ends with Track. McCowan was selected over SRT or Brimley corridor so it wouldn't steal ScamTrack's thunder. Similarly happened with the selection process for the relief subway. ScamTrack is like anti-gravity. Both subways get pushed away from where they otherwise should be because we're told it makes no sense to put them where they should be because something something ScamTrack is going to be a surface subway with subway like frequencies. How's that working out?

The city had an allegedly objective ranking process but in both cases the lesser of options magically get chosen. Why waste so much taxpayer time and money with the traveling road show presenting all of those fancy pie charts and score cards trying to pull the wool over everybody's eyes when the points don't matter in the end?

Obviously there was a quid pro quo of sorts. John must have promised Jennifer his backing on her own pet projects (her unfunded and legally untested rail deck park, her ill placed transit mall) on the condition she supported his signature re-election project.

Not sure why the transit mall on King is "ill placed". To me, that's the perfect place.

Anyway, you are greatly overstating the role of SmartTrack in choosing the SSE corridor. If SmartTrack never existed, the space would still be needed for RER. It is not impossible to place both the subway and the enhanced train service in the Uxbridge sub coridor, but it would be harder to build and operate that way.

Plus, there is a little issue of Kennedy station not being properly positioned for continuing the subway in the Uxbridge sub corridor; this issue is totally independent on SmartTrack.

As of competition for the ridership, that's totally irrelevant if the subway has no intermediate stations and the terminus of all possible routes is in the same place at STC.

 

[micheal_can]

Does one really need to ask? I'll give you a hint: it starts with Scam and ends with Track. McCowan was selected over SRT or Brimley corridor so it wouldn't steal ScamTrack's thunder. Similarly happened with the selection process for the relief subway. ScamTrack is like anti-gravity. Both subways get pushed away from where they otherwise should be because we're told it makes no sense to put them where they should be because something something ScamTrack is going to be a surface subway with subway like frequencies. How's that working out?

The city had an allegedly objective ranking process but in both cases the lesser of options magically get chosen. Why waste so much taxpayer time and money with the traveling road show presenting all of those fancy pie charts and score cards trying to pull the wool over everybody's eyes when the points don't matter in the end?

Obviously there was a quid pro quo of sorts. John must have promised Jennifer his backing on her own pet projects (her unfunded and legally untested rail deck park, her ill placed transit mall) on the condition she supported his signature re-election project.

Last I checked, the rail line that would be used for Smart Track is not close to the STC. They would still need some sort of connecting transit regardless.

 

[TOareaFan]

https://www.thestar.com/news/city_h...ubway-debate-referred-to-auditor-general.html

 

[TransitBart]

The context of the two projects is totally different. TYSSE is mostly built under hydro corridors, woodlots and empty land. SSE is not.

And that accounts for the engineering differences?

 

[OneCity]

https://www.thestar.com/news/city_h...ubway-debate-referred-to-auditor-general.html

Scarborough Transit Action - AKA - A cute spin-off name from the City's downtown political transit special interest group - TTCriders

There was far greater BS Politics for the Vaughan extension amongst billions of other Political debates going on right now. Thank god we have the majority of Politicians listening to the people and standing up for Scarborough Centre. If this Action group truly cares for Scarborough they could surely advocate for more stops or other lines on top of the Scarborough Centre connection instead of the same old backwards promotion of a rejected transfer laden plan which is thankfully never coming back.

At this point I just want to see real action

 

[nfitz]

Scarborough Transit Action - AKA - A cute spin-off name from the City's downtown political transit special interest group - TTCriders.

An interesting comment from someone who named themselves the same as Karen Stintz's aborted OneCity plan