The Engineer simply said that if the TBM was designed for soil (glacial till), then it can't go through rock. I think the strategy for DRL is the opposite. Go deep and always go through rock (i.e. TBM designed for rock).
Cut and cover is always cheaper than TBM, unless very competent rock is immediately below surface.
 
South of Bloor/Danforth I think the deeper the better. There's not really anywhere else in the city where bedrock is that close to the surface, and we should take advantage of it. And there are indeed advantages. Not all the time, but in an area as built as downtown there certainly can be. Also think a single large diameter bore is the ultimate solution for this stretch, with all stations having side platforms. Not unlike Montreal. With mined stations such as these it might complicate construction to some degree what with separate entrances or a small concourse level to switch platforms, but overall the benefits of having a single tunnel may outweigh two separate tunnels.

Also, for the entire stretch along Queen I believe it'd be wise to switch TBMs and bump the tunnel diameter to allow for a stacked setup - four tracks, two on each level. One level can be filled-in indefinitely, and stations can be reinforced/designed for expansion at some undefined future date. But there's no question doing this would be extremely forward thinking. Whether we wanted to use the second pair of track for express service, a shuttle, a secondary cross-core subway, a 501/504 LRT, etc... a larger central tunnel designed from the get-go for two levels would make any such project that much easier in the future.
 
I'd like to comment that a lot of peoples designs for the subway north of Bloor seem to be underground tunnels.

In Toronto we have a weird fetishization or blinder-vision of the fact that subways must be underground, even in areas outside of dense urban cores. This inability to look for alternatives is bleeding the city dry in the transit department.

Obviously downtown the first phase of the DRL must be underground, but its warranted due to density. Any other option would be intrusive.

We look at subway maps like New York and Chicago and say "hey why can't we have such a sprawling underground subway network?" without realising, 2/3 of their network outside of the core are elevated rail.

It all started in the 1970's when plans for an above ground section of the Yonge subway extension was shut down because of NIMBYISM.

Here you can see a model of the above ground proposal

ttc-york-mills-subway-model-1969.jpg


Apparently a loud, huge 401 overpass was OK, but not a quiet subway line.

(more info here: http://transit.toronto.on.ca/subway/5105.shtml)

Ever since this, from the Sheppard Subway, the Spadina Extension, and now the Scarborough Extension, we are unnecessarily building extensions into the suburbs underground at great cost.

We keep talking about that there is no funding for the DRL, but you know why? Because we are wasting billions in the suburbs by unnecessarily tunneling underground in areas that don't need underground subways!

Just a little rant, and really I hope it doesn't come off as angry and dismissive. I love everyones input into how they think the DRL should proceed after phase 1. But lets not make the same mistake over and over again, and remember that above ground alignments for the suburbs is how many other cities operate, and why they have such a sprawling large subway network while Toronto has tiny stubways.

Perhaps it will turn out that above ground alignments for the north part of the DRL won't work, but it should always be examined and investigated where possible.
 
I also understand that this alignment was less than ideal for various reasons

yrns-surface-subway-jpg.62937


But I think that we shouldn't throw the baby out with the bathwater.

Along Don Mills is the best choice, but there is tons of room on that street, with big grassy shoulders. A trenched, or elevated subway should be investigated along it.

The DRL could continue north underground along Pape, emerge in the Don Valley, run elevated across it to Don Mills Rd, and then run either elevated or trenched along Don Mills.
 
I'd like to comment that a lot of peoples designs for the subway north of Bloor seem to be underground tunnels.

In Toronto we have a weird fetishization or blinder-vision of the fact that subways must be underground, even in areas outside of dense urban cores. This inability to look for alternatives is bleeding the city dry in the transit department.

Obviously downtown the first phase of the DRL must be underground, but its warranted due to density. Any other option would be intrusive.

We look at subway maps like New York and Chicago and say "hey why can't we have such a sprawling underground subway network?" without realising, 2/3 of their network outside of the core are elevated rail.

It all started in the 1970's when plans for an above ground section of the Yonge subway extension was shut down because of NIMBYISM.

Here you can see a model of the above ground proposal

ttc-york-mills-subway-model-1969.jpg


Apparently a loud, huge 401 overpass was OK, but not a quiet subway line.

(more info here: http://transit.toronto.on.ca/subway/5105.shtml)

Ever since this, from the Sheppard Subway, the Spadina Extension, and now the Scarborough Extension, we are unnecessarily building extensions into the suburbs underground at great cost.

We keep talking about that there is no funding for the DRL, but you know why? Because we are wasting billions in the suburbs by unnecessarily tunneling underground in areas that don't need underground subways!

Just a little rant, and really I hope it doesn't come off as angry and dismissive. I love everyones input into how they think the DRL should proceed after phase 1. But lets not make the same mistake over and over again, and remember that above ground alignments for the suburbs is how many other cities operate, and why they have such a sprawling large subway network while Toronto has tiny stubways.

Perhaps it will turn out that above ground alignments for the north part of the DRL won't work, but it should always be examined and investigated where possible.
So much truth it hurts.
 
I'd like to comment that a lot of peoples designs for the subway north of Bloor seem to be underground tunnels.

In Toronto we have a weird fetishization or blinder-vision of the fact that subways must be underground, even in areas outside of dense urban cores. This inability to look for alternatives is bleeding the city dry in the transit department.

Obviously downtown the first phase of the DRL must be underground, but its warranted due to density. Any other option would be intrusive.

We look at subway maps like New York and Chicago and say "hey why can't we have such a sprawling underground subway network?" without realising, 2/3 of their network outside of the core are elevated rail.

It all started in the 1970's when plans for an above ground section of the Yonge subway extension was shut down because of NIMBYISM.

Here you can see a model of the above ground proposal

ttc-york-mills-subway-model-1969.jpg


Apparently a loud, huge 401 overpass was OK, but not a quiet subway line.

(more info here: http://transit.toronto.on.ca/subway/5105.shtml)

Ever since this, from the Sheppard Subway, the Spadina Extension, and now the Scarborough Extension, we are unnecessarily building extensions into the suburbs underground at great cost.

We keep talking about that there is no funding for the DRL, but you know why? Because we are wasting billions in the suburbs by unnecessarily tunneling underground in areas that don't need underground subways!

Just a little rant, and really I hope it doesn't come off as angry and dismissive. I love everyones input into how they think the DRL should proceed after phase 1. But lets not make the same mistake over and over again, and remember that above ground alignments for the suburbs is how many other cities operate, and why they have such a sprawling large subway network while Toronto has tiny stubways.

Perhaps it will turn out that above ground alignments for the north part of the DRL won't work, but it should always be examined and investigated where possible.
The TTC actually like underground lines better as they don't have to worry about Ice and snow building up on the line and interfering with equipment onit like switches and trip arms. On the colder days on both lines they have trains that are equipped with sprayers that they use to spread deicing fluid on the third rail too keep ice from building up on it. Because of the high current flowing through the third rail it snow melts on it but can become sticky and ucy if it's cold enough that's what crippled the TTC during the storm of 99, they had to run trains only in the tunneled sections of the lines.
 
The TTC actually like underground lines better as they don't have to worry about Ice and snow building up on the line and interfering with equipment onit like switches and trip arms. On the colder days on both lines they have trains that are equipped with sprayers that they use to spread deicing fluid on the third rail too keep ice from building up on it. Because of the high current flowing through the third rail it snow melts on it but can become sticky and ucy if it's cold enough that's what crippled the TTC during the storm of 99, they had to run trains only in the tunneled sections of the lines.

New York and Chicago seem to handle snow/ice on their surface rail just fine, thank you very much.
 
New York and Chicago seem to handle snow/ice on their surface rail just fine, thank you very much.

If you want to be rude, at least try not to throw around baseless claims like that.

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I'm in favor of above ground subways wherever possible, but it's incorrect to assume that snow and ice never cause problems. Not to mention that heat waves and strong winds have forced TTC slow orders on surface subways.
 

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If you want to be rude, at least try not to throw around baseless claims like that.

I'm in favor of above ground subways wherever possible, but it's incorrect to assume that snow and ice never cause problems. Not to mention that heat waves and strong winds have forced TTC slow orders on surface subways.

The DRL cannot even be above grade for a majority of its route. There are opportunities for it to be though, depending on the alignment. For instance, the path north of York Mills, crossing the 401 to Parkways Forest Dr (the intersection before Sheppard) could be elevated. Likewise, if the Parkside/Keele/Weston-Galt alignment is chosen for DRL West, elevated adjacent High Park and again north of St Clair.
 
I also understand that this alignment was less than ideal for various reasons

yrns-surface-subway-jpg.62937


But I think that we shouldn't throw the baby out with the bathwater.

Along Don Mills is the best choice, but there is tons of room on that street, with big grassy shoulders. A trenched, or elevated subway should be investigated along it.

The DRL could continue north underground along Pape, emerge in the Don Valley, run elevated across it to Don Mills Rd, and then run either elevated or trenched along Don Mills.

That alignment is stupid. Follows the DVP, then hits the northern edge of Thorncliffe Park, completely avoids getting close to Flemingdon Park, takes the old CN Leaside spur which has single family houses backing onto it, and then it follows DOn Mills. No wonder it failed.

I agree that elevated or trenched needs to be explored along Don Mills, but at the very least, cut and cover would be easy and cheap enough to do and reclaim the land above (and fulfill out underground fetish) in some areas.


Damn, that looks amazing! How the hell did that get rejected, it's like a north-south version of Old Mill!
 
Regarding the subway at York Mills the highway was built when that ar
Damn, that looks amazing! How the hell did that get rejected, it's like a north-south version of Old Mill!

A lot of rich people live in that area.
 
If you want to be rude, at least try not to throw around baseless claims like that.

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I'm in favor of above ground subways wherever possible, but it's incorrect to assume that snow and ice never cause problems. Not to mention that heat waves and strong winds have forced TTC slow orders on surface subways.

New York City has to worry more and more about sea surges as sea level rise due to climate change. (Unless you're a Trump supporter.)

 

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