[Steve X]

Trench with embankment slopes, or with vertical walls. The former requires slopes maybe 1:1 or flatter, so a a 5m deep trench requires 18m (60') of space.
The latter has a lot of earth pressure on the vertical walls, trying to push them in. Thus, it's actually cheaper to put struts across the top. Once your doing this, why not just put a roof on it and sprinkle a foot or so of topsoil along with grass. With the roof, it prevents debris from collecting in the trench, including snow, or thing being deliberately thrown.

Yes they could have totally trenched it with vertical walls in the middle of the street. Convert each major intersection into a bridge structure and have the platforms underneath the roadway. Any shallow construction would be built faster than a deep tube subway. The Mississauga Transitway didn't take 8 years to build. With room available, they could have temporary shifted eastbound traffic lanes 5m south and work in the middle. I don't know how challenging is it to build a shallow trench without relocating the gas line. I'm sure ML didn't want to relocate it in the first place and went with the tunnel. With a shallow subway, they definitely would not be able to for in a concourse and would need separate entrances for a side platform configuration. I don't remember what reason they gave for why a centre platform configuration is not possible. Probably cause the entrance would be stuck in the middle of the road.

Since we are now stuck with the tunnel option. Let's not argue why it's stupid and focus on the technical aspect.

Where would the launch and excavation shaft be located? I think it would be easier to just do two sets of TBM from west of Renforth and from west of Scarlett to and excavation shaft at Kipling. The tunnel doesn't have to align with Eglinton under the 401/427 ramp. This breaks the tunnel into ~3km each and take about 2 years to complete.

How would this connect to Renforth transitway station? The original plans called for a surface alignment right in the middle of the road passing through the traffic lights at Eg/Renfoth. I'm sure ML would hate that idea and has stated that they would operate ATO betweem Renforth and Mt Dennis station. So they'll likely would move the surface alignment onto the empty land just north of the transitway ramps.

I envision something like this. The blue is tunneled, green is at-grade and yellow is elevated (future phase). The station would be offroad opposed to in the middle of Commerce Blvd and they might as well grade separate the pedestrian walkway from the tracks like the transitway. It is the best to build a bridge to connect the LRT to the transitway. This also allows them to install fare gates to reduce fare evasion even through POP is required on the entire line. If they manage to install fare gates at every station from Laird westwards, it'll reduce the number of fare inspectors needed west of Yonge.

Even without stops at Rangoon and East Mall, they would need an emergency exit building as the tunnel between Renforth and Martin Grove is over 2km. That'll be around the 427.

With the surface alignment, there was a plan to build a stop right at Highway 27 with bus platforms on side of the highway connecting to the LRT with stairs. With a deep tunnel, that is obviously not going to work. Any connection with the 927 would have to connect to Martin Grove Station now.

I would suspect the station at Martin Grove would be very very deep to avoid both the Embridge gas substation and Mimico Creek. A bus terminal could be built here to connect to the 46, 111 as well as a branch of 927 and a possible extension of the 52G. With possibility of new routes serving south of Eglinton and short turning the 46 during low ridership times south of Eglinton. A shuttle between the airport can terminate here too as the connection to the airport might nit be built till they sort out where Union Station West would be located.

As riders shift to Line 5, ridership on express buses like 945 and 937 could terminate at Eglinton. Ridership south of Eglinton would be low. However there is barely any space to build a terminal at Kipling. They could short turn and run the buses into the Martin Grove terminal. At Islington, same story about space. It's okay, TTC didn't manage to build a bus terminal at Dufferin on both Line 2 and 5. Bus terminal at Royal York and Scarlett would not be necessary. Jane would benefit from one when ridership shifts to Line 5 although there is enough bus bays at Mt Dennis to make that redundant. A small bus loop at Jane can be sufficient.

 

[W. K. Lis]

Only one section really could be trenched: the Martin Grove/Eglinton/401 ramps, where two simple staircases and a elevator could lead down to a covered centre platform. That’d avoid some long signals. It’s too bad this wasn’t done at Victoria Park/Eglinton Square on the east end.

Perhaps there’s a case even for the elevated section through the Eglinton Flats at Jane Street. But that’s even too much.

You mean ramps. In case the elevator is out-of-service, people with strollers, luggage, bicycles, or wheelchairs can still access them.

From link.

 

[M II A II R II K]

I also wonder how this line is going to work when some of it is off the road with further apart stations and the rest is in the middle of the road with closer stops and traffic lights.

 

[denfromoakvillemilton]

Yes they could have totally trenched it with vertical walls in the middle of the street. Convert each major intersection into a bridge structure and have the platforms underneath the roadway. Any shallow construction would be built faster than a deep tube subway. The Mississauga Transitway didn't take 8 years to build. With room available, they could have temporary shifted eastbound traffic lanes 5m south and work in the middle. I don't know how challenging is it to build a shallow trench without relocating the gas line. I'm sure ML didn't want to relocate it in the first place and went with the tunnel. With a shallow subway, they definitely would not be able to for in a concourse and would need separate entrances for a side platform configuration. I don't remember what reason they gave for why a centre platform configuration is not possible. Probably cause the entrance would be stuck in the middle of the road.

Since we are now stuck with the tunnel option. Let's not argue why it's stupid and focus on the technical aspect.

Where would the launch and excavation shaft be located? I think it would be easier to just do two sets of TBM from west of Renforth and from west of Scarlett to and excavation shaft at Kipling. The tunnel doesn't have to align with Eglinton under the 401/427 ramp. This breaks the tunnel into ~3km each and take about 2 years to complete.

View attachment 236032

How would this connect to Renforth transitway station? The original plans called for a surface alignment right in the middle of the road passing through the traffic lights at Eg/Renfoth. I'm sure ML would hate that idea and has stated that they would operate ATO betweem Renforth and Mt Dennis station. So they'll likely would move the surface alignment onto the empty land just north of the transitway ramps.

I envision something like this. The blue is tunneled, green is at-grade and yellow is elevated (future phase). The station would be offroad opposed to in the middle of Commerce Blvd and they might as well grade separate the pedestrian walkway from the tracks like the transitway. It is the best to build a bridge to connect the LRT to the transitway. This also allows them to install fare gates to reduce fare evasion even through POP is required on the entire line. If they manage to install fare gates at every station from Laird westwards, it'll reduce the number of fare inspectors needed west of Yonge.

View attachment 236036

Even without stops at Rangoon and East Mall, they would need an emergency exit building as the tunnel between Renforth and Martin Grove is over 2km. That'll be around the 427.

With the surface alignment, there was a plan to build a stop right at Highway 27 with bus platforms on side of the highway connecting to the LRT with stairs. With a deep tunnel, that is obviously not going to work. Any connection with the 927 would have to connect to Martin Grove Station now.

I would suspect the station at Martin Grove would be very very deep to avoid both the Embridge gas substation and Mimico Creek. A bus terminal could be built here to connect to the 46, 111 as well as a branch of 927 and a possible extension of the 52G. With possibility of new routes serving south of Eglinton and short turning the 46 during low ridership times south of Eglinton. A shuttle between the airport can terminate here too as the connection to the airport might nit be built till they sort out where Union Station West would be located.

As riders shift to Line 5, ridership on express buses like 945 and 937 could terminate at Eglinton. Ridership south of Eglinton would be low. However there is barely any space to build a terminal at Kipling. They could short turn and run the buses into the Martin Grove terminal. At Islington, same story about space. It's okay, TTC didn't manage to build a bus terminal at Dufferin on both Line 2 and 5. Bus terminal at Royal York and Scarlett would not be necessary. Jane would benefit from one when ridership shifts to Line 5 although there is enough bus bays at Mt Dennis to make that redundant. A small bus loop at Jane can be sufficient.

This is at 2 percent design. Anything can happen in 25 months.

 

[Steve X]

This is at 2 percent design. Anything can happen in 25 months.

They are asking for companies to bid, they would have figure out how many TBMs, how long is the tunnels and where to put the launch shafts by now.

Things like where to put a bus terminal isn't an engineer's job to figure that out. At 0% design, they need to know so they can start the first 2%.

Detail design is exactly how deep is the floor and ceiling. How many steps in a staircase. How many inches in between tunnels, etc. Not what route feed into the station.

 

[44 North]

Trenched (similar to Ottawa) or the Green Line extension in Boston might be a good option, given it's the lower cost for station construction and lower tunneling costs.

If the goal is to reduce noise, not interfere with intersections, remove eyesores, and increase reliability, it could work. There's plenty of space to trench.

Trenched is pretty bad from an urban planning lens. Think about the reduced permeability. Elevated gets a lot of flack, but at least you can pass under it unhindered. Trenched? You got a giant chasm severing entire communities in twain. Better than TBM under Eglinton West, but only for the reason of costs.

Do wonder if Eglinton West should be a separate line. If the Prov now wants to revert their Crosstown into something resembling a subway on the western end, why not just go all the way. Make it a subway line. Perason to Mt Dennis end-to-end. No pantos so smaller tunnels, trains are lighter, nice subway-like high platforms. Wonder why they didn't give this a thought.

 

[Amare]

Having a trenched line on Eglinton West would have worked just fine since the communities are already there are tucked in behind the former Richview Expressway corridor. I would have rather had a giant gaping trench, then the quasi mish-mashed development mess we're seeing take place along there today.

 

[Steve X]

Trenched is pretty bad from an urban planning lens. Think about the reduced permeability. Elevated gets a lot of flack, but at least you can pass under it unhindered. Trenched? You got a giant chasm severing entire communities in twain. Better than TBM under Eglinton West, but only for the reason of costs.

Do wonder if Eglinton West should be a separate line. If the Prov now wants to revert their Crosstown into something resembling a subway on the western end, why not just go all the way. Make it a subway line. Perason to Mt Dennis end-to-end. No pantos so smaller tunnels, trains are lighter, nice subway-like high platforms. Wonder why they didn't give this a thought.

Nothing wrong trenching. The Mississauga transitway and Yonge Line looks fine to me. They can cover it and repurpose it for recreational use later.

What's the point of using subway cars from Pearson to Mt Dennis and then force everyone off to a LRV train? The plan for at grade sections beyond Renforth which they can't do plus they'll have to build another MSF and buy another set of trains? High platforms isn't superior and they could fit both tracks in one tunnel with narrower trains (which Montreal did). With the needs of only 42 LRVs out of 76 on opening day, they'll have plenty of spares around.

Some folks at ML did envision a grade separated Skytrain line along Eglinton but that's dead since LRVs is selected. Even if they did give it a through, it is not worth it. I'm sure if they were to redo the Crosstown, LRVs would not been selected. This is one David Miller legacy as part of TC and the streetcar option. The LRVs were "cheap" and ML made them more expensive themselves.

 

[denfromoakvillemilton]

They are asking for companies to bid, they would have figure out how many TBMs, how long is the tunnels and where to put the launch shafts by now.

Things like where to put a bus terminal isn't an engineer's job to figure that out. At 0% design, they need to know so they can start the first 2%.

Detail design is exactly how deep is the floor and ceiling. How many steps in a staircase. How many inches in between tunnels, etc. Not what route feed into the station.

I'm aware. I was a project manager. My point is that it's still can be changed significantly after any town halls. I'll wait for next year to see how much progress is made.

 

[44 North]

Nothing wrong trenching. The Mississauga transitway and Yonge Line looks fine to me. They can cover it and repurpose it for recreational use later.

What's the point of using subway cars from Pearson to Mt Dennis and then force everyone off to a LRV train? The plan for at grade sections beyond Renforth which they can't do plus they'll have to build another MSF and buy another set of trains? High platforms isn't superior and they could fit both tracks in one tunnel with narrower trains (which Montreal did). With the needs of only 42 LRVs out of 76 on opening day, they'll have plenty of spares around.

Some folks at ML did envision a grade separated Skytrain line along Eglinton but that's dead since LRVs is selected. Even if they did give it a through, it is not worth it. I'm sure if they were to redo the Crosstown, LRVs would not been selected. This is one David Miller legacy as part of TC and the streetcar option. The LRVs were "cheap" and ML made them more expensive themselves.

Yonge is pretty good. Bridges less than 100m apart so barely dented the existing porosity and preexisting urban built form, lined with crabapple trees. Don't think anyone's building anything like that anymore. Sauga Transitway on the opposite end of the spectrum lined with ultra suburban office parks or expressways to begin with so not the greatest example for a corridor like Eglinton. If we want to develop and urbanize an arterial, of the options of in-median, trenched, underground, and elevated - trenched would be the most detrimental and difficult to work around. If you're arguing that we could put a cover on the trench, then ok but that's not trenched.

As for the notion of having a separate subway line west of Mt Dennis, there's some merit. One could simply take the talking points from the Prov's Ontario Line report. Smaller, lighter trains, etc. Could connect to MCC with tweaks to the Transitway and finally building the direct grade-separate connection from the transitway, allowing them to join this newfound subway revolution we're supposedly in. Obviously LRVs are more flexible in that they can get onto roads mixing with cars, but there are drawbacks too. Heavy, big panto that's not retractable requiring large tunnels, costlier trains, lower capacity per sq foot on account of being low floor. And the infrastructure, we could build stations half the length of the Crosstown ones and still have enough capacity for the next millennium, two millenniums if we're to accept the capacity numbers peddled in the Ontario Line report.

 

[Rainforest]

As for the notion of having a separate subway line west of Mt Dennis, there's some merit. One could simply take the talking points from the Prov's Ontario Line report. Smaller, lighter trains, etc. Could connect to MCC with tweaks to the Transitway and finally building the direct grade-separate connection from the transitway, allowing them to join this newfound subway revolution we're supposedly in. Obviously LRVs are more flexible in that they can get onto roads mixing with cars, but there are drawbacks too. Heavy, big panto that's not retractable requiring large tunnels, costlier trains, lower capacity per sq foot on account of being low floor. And the infrastructure, we could build stations half the length of the Crosstown ones and still have enough capacity for the next millennium, two millenniums if we're to accept the capacity numbers peddled in the Ontario Line report.

But that will create a very unpopular linear transfer at Mt Dennis, for a very modest cost reduction. Noone from the west will be going just to Mt Dennis, and relatively few will want to transfer to RER there. The majority of riders coming from the west will want to reach the subway, either at Allen Rd or at Yonge.

 

[W. K. Lis]

But that will create a very unpopular linear transfer at Mt Dennis, for a very modest cost reduction. Noone from the west will be going just to Mt Dennis, and relatively few will want to transfer to RER there. The majority of riders coming from the west will want to reach the subway, either at Allen Rd or at Yonge.

IF... and it's a big IF... they could continue with the discount fare between GO, UPX, and the TTC, then people would want to transfer at Mt. Dennis Station to get to the Union Station. Especially to get to and/or from a game at the Rogers Centre, Scotiabank Arena, or trade shows at the Toronto Convention Centre.

 

[CapitalSeven]

Do we know whether the undisturbed green space this could be built on will be densified? That might justify the hideous expense of digging a bored tunnel and deep stations for 4000 ppdph. Or will it be left there as a monument to "planning" under the Fords?

 

[Steve X]

IF... and it's a big IF... they could continue with the discount fare between GO, UPX, and the TTC, then people would want to transfer at Mt. Dennis Station to get to the Union Station. Especially to get to and/or from a game at the Rogers Centre, Scotiabank Arena, or trade shows at the Toronto Convention Centre.

Most people use transit to commute to work or educational institute. This is what public transit is built for to help the economy flourish. So they are definitely not going to Union. I would say less than 5% of the riders on Eg west would end up near Union.

Union is one of the worst places to transfer between rapid transit as Line 1 and GO/UPX are 5 minutes apart through huge crowds of people.

 

[W. K. Lis]

Most people use transit to commute to work or educational institute. This is what public transit is built for to help the economy flourish. So they are definitely not going to Union. I would say less than 5% of the riders on Eg west would end up near Union.

Union is one of the worst places to transfer between rapid transit as Line 1 and GO/UPX are 5 minutes apart through huge crowds of people.

The south core, the area of downtown Toronto SOUTH of Union Station, is being developed with more commercial spaces. That means the employee's will be using the UPX/GO from Mt. Dennis Station to get an "express" ride downtown.