This series works through the three-part presentation of the proposed Eglinton LRT design that appears on the project’s website. Part 1 brought us east from the Airport to Black Creek, and Part 2 covered most of the remainder east to Warden.
Part 3 of the presentation deals with the short section from Warden to Kennedy as well as various construction issues, notably an alternative scheme for tunnelling.
Birchmount Stop: Like many others, this intersection gets the left turn relocation treatment, but with farside stops that allow the retention of right turn lanes.
Kennedy Station: This station will be a complex project in its own right linking the existing subway and GO services to the Eglinton LRT, the Scarborough-Malvern LRT and the S(L)RT. This station and its surroundings have always been rather sad as a major transit terminal both because it hides beside the Eglinton overpass, and because Scarborough Council, in its wisdom, chose to downplay the importance of this location for development to avoid competition with the Town Centre.
Three options are given for the Eglinton LRT’s route into the station, two on the surface and one underground. All appear to be designed to use the existing passageway from the kiss-and-ride into the mezzanine level of Kennedy Station, and it is unclear how this structure would be affected. It is also the unused loop from the Scarborough RT above.
An alignment is also shown for a Scarborough-Malvern loop around the existing bus platform, although how exactly this line would get across the rail corridor is unclear.
From other discussions, we already know that the SRT station will move underground as part of the line’s reconstruction with a connection at the mezzanine level.
Various layouts are possible, but we need to see more details including provision for transfer moves between buses, LRT and subway. Demand on the bus loop itself will not be significantly changed until both Eglinton LRT lines open and replace east-west bus services.
Depending on the technology choice for the SRT, there may a requirement for tracks linking this route with the east-west Eglinton lines. Also, if the SRT through-routes with Eglinton (not a good idea to my mind because Eglinton is long enough already, and has a different service level requirement from the SRT), the track connection would have to include the station. If this were only a service connection for carhouse moves, then there would be more flexibility in the design.
Construction Methods: Three basic types of construction are introduced on Panel 57 (Page 3 of the PDF) — surface construction in the manner of streetcar lines, twin tunnels such as are used on Yonge north of Eglinton and on the Sheppard line, and cut-and-cover construction with a box tunnel commonly seen on much of the Yonge and B-D subways.
Twin bored tunnels reduce the construction effects at street level, except at stations, but can be more expensive because they tend to lie deeper underground.
Station construction for this line may be a bit less intrusive than conventional subways, but this depends on whether provision is made for eventual expansion to 500-foot platforms. If so, then the station structures would need to be built out to that size even though it may never be used. Moreover, at that eventual length, all stations would need provision for two separate exits to meet fire code.
Tunnelled lines tend to be deeper, and this affects station structures both for cost of construction and for the facilities (elevators and escalators) needed to get passengers between surface and platform levels.
Panel 62 shows an alternative construction with a single large tunnel 13m in diameter. This technique has certain advantages:
- A single tunnel is cheaper to build than two small ones.
- For street sections where space between building foundations is at a premium, there may not be enough space for twin tunnels plus the clearance needed between them for structural stability (the “column” of earth separating them).
- As shown on the display, stations can be accommodated within the tunnel itself and do not require separate construction except for the vertical access paths. One disadvantage is that the lower platform is further under the street than would be the case with a common centre platform.
- Lengthening a station would not require additional pre-construction provisions.
This tunnelling method has been used for part of the new Line 9 in Barcelona, and is proposed for an extension of the Washington DC system.
The project is now accepting public comments on the proposed designs, and will return with another round of meetings in November. These will include design details for complex locations such as the junctions with other lines, and the alignments at Weston and at the airport.
Steve Munro 
Could you please comment on the impact that the single-bore approach would have on portal design?
Steve: Since it is possible to have two tracks side by side in the tunnel, the changeover to a single level would happen near the portal mouth, and it could emerge in a conventional box structure.
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It’s a little surprising to see so much design work for the Eglinton line. It seems like it was just yesterday that Transit City was announced! A few questions Steve:
Are they still going to build the central tunnel to subway standards? That was the original plan, but it certainly doesn’t look like it will be anymore.
Steve: The single bore tunnel can be used by any technology, and is the easiest one for accommodating station expansion. However, any conversion must address the low platform LRT versus high platform “subway” operation. An important point here is that nothing prevents the Eglinton “subway” from being isolated with longer trains of LRT cars. After all, the new Transit City cars will be longer than subway cars, and you don’t have to run “subway” technology just because the line is underground. The proposed carhouse at Black Creek is located in a way that trains would never have to operate on street between Weston and Leaside, and a “subway” extension to Don Mills would not be difficult to build given the available land along Eglinton.
Will the tunnel section have ATC? It would be especially useful if Eglinton is interlined with the Don Mills and Jane lines.
Steve: There have been suggestions that at least some form of cab signalling, will be used. Whether full automation is actually needed is another matter.
It seems like you’re pretty confident that the Don Mills line will end at Eglinton, where it would meet the DRL. But the current plans for the intersection don’t reflect that, and the DRL isn’t really on the TTC’s radar at all, as far as I know. Do you know something we don’t?
Steve: City Council has asked for a detailed report on DRL options, and this line at least to Danforth is part of the Metrolinx RTP. There has been a major problem with TTC planners being stuck in the mindset and routing options of the original Don Valley corridor study, and they have three routes coming all the way down to the BD subway (at Castle Frank, Broadview or Pape). None of these is practical as a surface operation, but this doesn’t stop them from trying.
Once it is accepted that the line (whatever the technology) from Danforth to at least Thorncliffe Park will have its own dedicated structure (tunnel and bridge), then a northerly extension of the DRL is quite logical. At the very least, the Eglinton study should allow for this possibility.
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One other question is will this, and the other, light rail transit lines be operating 24/7? They are to be POP. If enough crossovers are employed on the route, maintenance can be done on one side, while the other side could alternate with the wider headways in the morning hours. So where would the crossovers be, for overnight maintenance and short-turns?
Steve: As far as I know, the TTC plans the usual hours of “rapid transit” service with surface bus operations at night. I have no idea where crossovers, etc., might be on the route. Come back in November when we see the more detailed version of the line.
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Would Zeppelins, flying majestically through the air, cause any of these complicated issues and problems? Think of the tourism.
Steve: Motorists will be distracted by the aerial displays, traffic would slow to a halt, and gridlock would result. All turn lanes will have to be reoriented so that the Zeppelins were invisible. This could be challenging. Possibly we may put the roads underground leaving the surface for landing pads at major destinations.
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The board for Kennedy Station is… how should I put this mildly?, unimpressive, and frankly contrary to what staff have said at earlier open houses.
The Morningside line was supposed to be capable of through-routing with Eglinton, the current design doesn’t facilitate this at all. The LRT should extend above the existing tail tracks and then swing back under Eglinton.
That proposal to relocate the existing brand new GO platform also makes you wonder how much thought and co-ordination was going on when GO first built the Kennedy station for their trains.
Steve: I think we are seeing the effect of many cooks in the same kitchen.
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Adam Hawkins Says:
July 6th, 2009 at 12:25 pm
“It’s a little surprising to see so much design work for the Eglinton line. It seems like it was just yesterday that Transit City was announced! A few questions Steve:
“Are they still going to build the central tunnel to subway standards? That was the original plan, but it certainly doesn’t look like it will be anymore.”
I asked this question of one of the young subway engineers and he said that the diameter of the tunnel for the LRT is slightly larger than needed for a subway because of the extra vertical clearance for the overhead. If they did do a large single bore, there would be space to build a short high platform to be used by high platform short trains while they replaced the rest of the low platform with high platform before introducing full length high platform service. You would have to shut down the line for conversion with the other systems if you did not pre-build 500 foot long platforms.
I also seem to remember that there will be air shafts near the stations that can be used for emergency exits or they could walk 800 m to the next station as there is no third rail.
Steve jumps in: But if the line is converted to true subway, then it would acquire a third rail unless we would run that route with pantographs. This would create an isolated line with unique equipment.
I think that the TTC was hoping to use the Brentcliffe station for the Leslie bus. A woman from transportation said that there would be surface buses from Brentcliffe to Yonge. I agree that they go under the new road to be built east of Brentcliffe and should also go under Don Mills road as that is a nightmare intersection in rush hour.
Steve: Brentcliffe is not that far from Laird Drive, and the Leslie bus is not exactly the most frequent of routes. Stations should be located where they are convenient for riders, not for a connection to an infrequent service. I could even make an argument for amalgamating the Leslie bus with Leaside.
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This is a bit long so bear with me.
Steve: I am publishing this comment in the interest of discussion, but my own take on the matter is quite clear. Claims for a full blown-subway on Eglinton are, so to speak, overblown, especially in the context of a downtown relief line from, say Weston to Don Mills and Eglinton. If we build a subway, that’s where it should be, not on Eglinton.
The Eglinton LRT subway, if built as proposed with a single bore tunnel, will not need to have allowance for future expansion pre-built into the stations (other than gradient constraints), and there is nothing to prevent running frequent service with LRV trains in the “subway” rather than converting the line to a conventional high-platform subway. This approach leaves the outer parts of Eglinton with surface operation.
Demand in this corridor will be distributed over a wide area and will be bidirectional. We must be careful in projecting a total ridership figure into a peak point count.
There are many aspects of this plan that are disappointing to say the least. In spite of the TTC’s own analysis regarding projected ridership growth levels along the Eglinton corridor, one needs to bear in mind that as a Crosstown route the Eglinton Line will do far more than serve a local populus adjacent to the actual street. Eglinton could easy well siphon away tens of thousands of commuter traffic heading inbound towards the Bloor-Danforth subway line daily, making it a credible alleviator relief line in its own right and can simplify interregional cross-GTA commutes as well. Now after hearing about the Crosstown LRT plan in greater detail, I’m more convinced than ever before that a subway belongs in this corridor. And if the LRT’s expenditure is already climbing astronomically up into subway range and beyond, why not?
Firstly, PIA and the Airport Corporate Centre. ACC is a very large business park and most area employees will certainly not be within easy walking distance of a “rapid transit” station. They’ll continue to use feeder buses as they do today connecting to the RT service. This is why after Martin Grove the subway alignment could and should skip Renforth altogether and instead via a hydro corridor, which conveniently runs perpendicularly up to Hwy 27, run elevated across Dixon/Airport Rd to the airport’s Terminal 1 where the station can seamlessly connect with the People Mover tram. This would in the process include station(s) at Hwy 27 and/or Carlingview (transfer point with the 112 bus) where a number of airport area hotels, offices and conference centers are congregated. Note too that an Hwy 27 Stn would also be the jump-off point for Woodbine Entertainment, Humber College, even Albion Mall area-bound excursions; lessening the need for a full-length Finch West LRT corridor; which commuters coming in from the south and west may find cumbersome to use.
From Martin Grove to Royal York, the line could be done in a mixture of at-grade and open-trench configurations, and be elevated from Royal York to Mount Dennis Stn with Scarlett Rd Stn occurring on the SW corner of the intersection (making the western exits near grade level for easy access to Mulham Pl). Conversely I recommend skipping Jane Street for cost and travel time advantages due to the unlikelihood of redevelopment of the surrounding parklands and low walk-in prospects other than it being an arbitrary transfer point for the Jane LRT.
Mount Dennis Stn rather has quantifiable significance. It could one day be the western terminus of a Downtown subway line and a direct transfer connection with GO Transit. Given its “hub” appeal status and the reality that Weston Rd from Jane to Eglinton has more residents than the latter, a Jane LRT would be far more beneficial to riders by running underneath Weston Rd through this short stretch (only a Queens Quay-esque stop at Ray Ave is required within the LRT tunnel). This sets up a rationale to continue either LRT or subway technology adjacent to the Weston-Galt Sub between Bloor and Eglinton, further alleviating our system’s core lines. Such a subway connection nullifies any purpose/function for Jane LRT south of Eglinton. It also retains the close-knit stop spacings of the 35 Jane bus south of Weston Rd, which local residents will appreciate. The 35 bus could also take over the 32D’s loop around Emmett/West Park, whilst long-haulers from North York and Vaughan would be getting their limited-stopping LRT shuttle service.
Keele North Stn’s about the only thing I like so far. I think it’d be a good idea to merge the 32C Trethewey bus with Route 59 Maple Leaf such that both ends of the route terminate at a metro (service along Church St and Gary Dr would be bi-directional on a single routing). Caledonia Stn however is too far over from its namesake. Were the station to be centered underneath Croham instead, with exits on both ends, there’d be no reason to time-consumingly detour the 47 bus when a simple on-street transfer could be done instead. The future GO connection and access to Westside Mall/Gabian Way is still achievable with customers not having to walk further than 100m over. Dufferin North should have some sort of on-street loop where the 90 bus can turnaround, and possibly include a westerly exit onto Ennerdale given the huge spacing gap between Dufferin and Caledonia. Why are these underground stations only 90m in length anyway, if the TTC has stated they’ll one-day be accommodating HRT trains? They should be subway standard length (150m) whereby these spacing gap issues are minimized.
Chaplin Stn is okay but should have exits out to Spadina Rd, seeing that the area’s comprised of several apartment complexes, a large high school and library. The gaps through East York are odd. Laird Dr is the principle street of Leaside, so why exclude it? A Brentcliffe Stn could easily be merged with Leslie, there’s little reason for two separate stops here as it’s mainly parkland. Put Brentcliffe Stn on a elevated guideway parallel to Aerodrome Cr, such that it’s level with the housing development to the east of Brentcliffe with escalators/elevators leading down to street level just to the west of Leslie/Eglinton. Having the subway continue along this elevated guideway through the Don Parklands (all the way til Bermondsey) is a great way to conserve funds not to mention readily provide easy access to major destinations close-by but not directly along Eglinton proper itself (i.e. the Science Centre and the Wynford Hts-Concorde business park just northeast of the DVP). At Don Mills of course a side-of-the-roadway transfer to the DMLRT would be possible as would access to a shallow tunneled DRL.
Separate Victoria Park and Pharmacy stops would not be needed were this a subway either, particularly if the station’s centered on Eglinton Square. It is quite possible to route the section through the Golden Mile at-grade, although it would close off access to some minor streets and freeway-dize the Warden intersection. Were a new southwest-northeast configured station platform to be designed for the Bloor-Danforth Line, this new Eglinton subway could takeover operations through the existing east-west platform at Kennedy Stn. This sets a precedence for continuing the B-D Line northeast to the Scarborough Centre through the hydro corridor and the parkland in-between Brimley and McCowan north of Lawrence. Such an acquisition would also bolster the case for continuing subway operations underneath Eglinton from Birchmount through to Kingston Rd (with a terminus likely in the vicinity of Guildwood Pkwy-Scarborough Golf Club Rd). This would minimize the need for a Scarborough-Malvern LRT as through-service BRT operations along Kingston Rd could seamlessly connect outer nodal areas such as West Hill, UTSC, Highland Creek and the Zoo to the subway at this location (as well connect to the B-D and DRL subways further southwest).
The costing for all this could be very affordable, from as little as $150 million/km for the at-grade portions and $175 million/km for elevated/open-trenched options (at least that’s what the international standard is). And the funding for this subway would already exist per the reallocation of preexisting granted Transit City funding (9-13 Billion federal dollars). So a 37 kilometre subway line stretching from the airport to Guildwood using a mixture of above-, at- and below-grade configurations may cost just a billion and a half more than the $4 Billion estimates of a mere 31km LRT line lacking true signal priority nor exclusive right-of-way and with one too many minor stations where instead a reduced service parallel bus route could easily serve the low-density residential areas in-between the major arterials. This would still leave ample funds over with which to create a citywide mass transit network but with more emphasis of course on affordable BRT routings over costlier light-rail. Bolstering our existing network however by merely introducing more limited-stopping express bus routes (as is being proven successful along Finch East and Wilson) at no additional cost will ensure that everyone gets a rapid service but areas already exhibiting near subway levels of demand (over 153,500 customer trips or 9594 pphpd begin or end along the Eglinton corridor on a daily basis) should be treated within that regard.
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A note on ATC: perhaps, of all places, the underground portion of Eglinton is actually a good candidate for platform edge barriers (which would apparently necessitate ATC). My logic: the low platforms will increase the allure/possibility of unauthorised track entry by ‘unscrupulous’ or wayward customers, possibly forcing lower-speed operation. Thoughts?
Steve: For counterexamples, please see Spadina Station, St. Clair West Station and Union Station Loops. I really am tired of adding bells and whistles to transit projects, especially if this creates linkages such as “doors need ATC”. The “unscrupulous” will always find their way to track level, doors or not.
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I think that it is essential that it be possible to convert the underground sections to some sort of subway operation in the future, as 30 years in the future Eglinton will be much more important that it is today, and density will be high enough that reliever lines will not help. Underground infrastructure is expensive, very difficult to expand once built and designed for the very long term (some subways are over 100 years old). Surface infrastructure is cheap and easy to expand or move underground when necessary. Rapid transit lines have a long history of in the long term, attracting development (both near the line and via feeder buses) and eventually reaching capacity and requiring expansion.
I have to disagree with your idea of using long trains of LRVs for underground “subway-like” operations. You would need trains of 4 of them to be equivalent to a 6 car subway train, which would require some sort of oddball design as I strongly doubt that unmodified LRVs are designed for operation in 4 car trains. Furthermore, they would be confined underground as they cannot run on city streets due to length. Thus you would need some sort of oddball low-floor subway design which is unique to Toronto. High platform cars with a narrower loading gauge (think Montreal) are a more realistic possibility but again this would forever eliminate the possibility of interlining with the existing subway at Kennedy. The new Eglinton LRT subway should be designed to handle the loading gauge of a standard Toronto subway car, with provision for expansion to 6-car subway platforms.
Steve: This is already technically possible as discussed elsewhere in this thread. However, six-car subway trains represent a big increase in capacity and in the short term LRT cars will work just fine. As I mentioned, the Black Creek carhouse would connect to the portion of the Eglinton line that will likely be grade separated and the issue of running 4-car trains on street is moot. As for technical capabilities, that’s a question of setting up the electronics on the trains properly. LRT and subway cars are simply different bodies on the same underlying technology.
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Excuse my ignorance, but would not building a single bore tunnel, that is big enough to fit two LRV’s be more expensive than two tunnels, as there is more “dirt” being moved? Also, would they not need to also be wide enough to fit a “station”?
I don’t understand how this can be cheaper, but if it is, I say go for it.
Steve: It’s not the quantity of dirt that is the prime factor here. Also, if you look at the display panels, you will see that a station fits into the tunnel quite nicely making them cheaper to build.
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Really, Steve, this is getting ridiculous. This line needs to be EMUs or nothing at all.
Steve: An “EMU” is nothing more than a subway car or LRT dressed up in the guise of a commuter rail car.
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I know these stations are supposed to be low cost, but especially with the single bore tunnel they’re reasonably deep. Any chance of having three escalators where the TTC plans to install two, so that there’s always a backup? If the stations are unstaffed, I shudder to think how long it’ll take to restart an escalator after some kid hits the emergency stop button.
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Emus? I thought we had already decided on swans.
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With regards to escalators I have seen in other countries on other systems, most notably in Budapest Hungary where the stations are unstaffed that there are 4 escaltors, two off and two on in both directions at all times.
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Swans only work on the Don. Emus in tunnels are necessary to avoid flooding. Sand will generously be provided should head burying become necessary.
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Escalators are neither fish nor fowl – fully accessible (elevators) or easy to maintain (stairs). It might make the LRT more palatable for airport passengers, for instance, if multiple large elevators made it easier to bring suitcases to track level.
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I feel like we need a post about the difference between a streetcar and a subway. When it comes down to it they are both electric. I imagine based on some of what I’m reading from the go electrification that overhead power is better in a number of respects, safety and voltages that can be delivered without arcing. Are there limitations on how many streetcars can be put in a train. How is a high platform any different from a low platform. Can streetcars be ran as a subway, ie fares collected at the station. Can streetcars be built wider to provide the same capacity as a subway and those cars only operated in the tunnels/right of ways? Could a streetcar use a third rail and we could call it a subcar would that be enough to end the debate? For that matter could a subway be converted to use overhead and we could run them down the streets and call it a streetway?
Steve: First off, the fundamental difference between “light” and “heavy” rapid transit (streetcar or LRT vs subway, broadly speaking) is that a “light” implementation does not require a completely segregated right-of-way and allows pedestrians, vehicles, etc. to cross the right of way. Whether we actually let people do this is another matter, but the point is that nothing inherently prevents it.
By that standard, to qualify as “light”, a route must not use third rail pickup, and operation must be by operators rather than computers. Platforms for “light” systems typically are low, street level but this is not absolutely necessary as it is possible for streetcars to run with high platforms and with grade crossings (Calgary is a good example).
High and low platforms can be a bit confusing due to evolution in technology. Before low-floor cars were common, everything was high-floor because clearance was needed over the supporting trucks. Subways were built with platforms at the floor-height of cars, while streetcars used steps so that people could access them from the pavement. Again in some cases, a streetcar system might be built with high platforms (Calgary again), but this increases the cost and complexity of surface stops because the stations have a more significant physical presence.
Streetcar and subway electrification typically is done at 550 to 750 volts DC, and all (or most) axles are powered. Power pickups are on each car and so there is no problem with trainlining power from a single contact with the overhead or third rail. Railways are typically powered at 25KV to reduce transmission losses. This voltage requires greater clearance to avoid arcing both for the overhead and for power equipment on trains. That’s why railway overhead will be suspended with longer insulators than you would see on subways or streetcar systems.
Streetcars can run in subways, and have done so for over a century with Boston being the oldest streetcar subway in North America (1892). The number of cars that can run in a train is generally determined by the surface parts of routes where the trains have to fit into on-street infrastructure (waiting platforms, etc.). Cleveland ran five-car PCC trains on the Shaker Heights line at one time, and three-car trains of PCCs used to be common in Boston. These days, the cars are longer, and so the trains have fewer units.
Streetcars can also vary in width to carry more people, but the basic limitation is of road geometry for lines that occupy regular street lanes, or isolated rights-of-way that were designed for narrower cars. Toronto subway cars are unusually wide, and although this gives them greater capacity than cars on some other systems, it also increases tunnelling costs.
Fare collection can be on-board or through station payment. We have a mixed system in Toronto where most of the time, streetcars are pay-as-you-enter, but at stations fares are paid at the entrance.
Mixing subway cars and streetcars raises many problems including the difference in floor height, and the greater dynamic clearance required for subway cars due to their length and width. For example, an ALRV streetcar is roughly the same length as a T1 subway car, but the ALRV pivots in the middle, and is narrower. This allows it to fit in locations a subway car would not fit.
There is a lot of overlap betwen “light” and “heavy” rapid transit, and there is no simple cutoff point between them. Above certain demand levels, surface operation is impractical because of competition for road space, both for the trains and for the pedestrians walking to and from the stations. Some places don’t have available right-of-way in which a streetcar right-of-way can be added, and this might force underground operation for a demand that would otherwise be borderline. The essential difference is that a “light” implementation can be built “light” where appropriate.
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I would like to see the Subway get extended from Kennedy east along Eglington to Kingston Rd. They could have a station on this alignment at Brimley Rd and Eglinton serving the 12B Bus and the 21 bus. Their could be another station at the Eglinton GO station servicing the 9 bus route and the GO station and finally they could have the Kingston Rd station servicing the 113 Morningside bus, 86 Scarborough east bus and the 34 Eglinton east bus. The 34 bus would only enter the Kingston Rd Station and Kennedy station. The Eglinton LRT would service Eglinton from Kennedy station to Yonge/Eglinton. While I’m dreaming like this I would like the Bloor line extended westward from Kipling Station to Sherway Gardens with some kind of platform for whatever kind of system Mississauga ends up with. I figure the Yonge/University/Spadina might be extended on both ends so why not the Bloor Danforth line.
One thing I do appreciate about the plans talked of in the article it that the SRT will have and one level down platform for the SRT. That will make transfers from Subway to SRT just one level. These types of plans for transit show the TTC is really trying to make tranferring and commuting much more convenient. This type of planning will surely increase ridership.
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I welcome the last comment. A few years ago TTC wanted to put LRT in some sort of huge triangle from Eglinton to Kingston and back SW to Victoria Park and Kingston Rd. and again N to Vic Park station. I have visited the area put down my rose-coloured glasses , and I realized that Eglinton east to Kingston Rd. is really ripe for a huge re-development. The southern side could be completely destroyed, the tringle at McCowan/Brimley/Eglinton is full of weeds and cannot be used for anything. Conditions (1) TTC would not be able to reduce number of trains on the Bloor-Danforth until about 1030. (2) – this change may reduce a need for DRL.
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From this thread I gather that the cost of building an LRT tunnel is more than a Subway tunnel. Where would one get a copy of the cost comparison report?
Steve: There isn’t a specific comparison. However, tunnel costs are tricky. The important difference for LRT is that the cars take their power from overhead wires that tend to require more clearance than a subway train. That applies more to box tunnels than to round, bored tunnels. With a box tunnel, there must be enough headroom for the contact wire and the pantograph on top of the car. Transit City cars will not use trolley poles, and this reduces the headroom needed in the tunnel.
Standards for round tunnels have evolved over the years, and they are now wider for safety reasons. Making them wider also makes them taller. It is my understanding that there is enough room in the Sheppard Subway tunnels for overhead power, and the Spadina extension tunnels will be even larger.
The scheme for a single large tunnel for Eglinton is probably overkill. It may solve some problems, but it creates others including depth and the larger amount of spoil that must be removed. Much of the tunnel will be empty except at stations where the platform structure will use the spare width. There are tradeoffs in every design, and I believe that the TTC is still trying to decide which one to use.
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I’ve been reading as much as I can find about the TransitCity plans, but there’s one thing I haven’t been able to get a clear answer to:
Since there were originally plans for a Eglinton Subway (with some construction) that was canceled, doesn’t it make sense to build the Eglinton LRT subway (single tube or twin tubes) so it is designed to fit subway trains even though it will initially be used for LRT trains? When the Eglinton LRT needs to be upgraded to subway capacity in 50 or 75 years, the tubes don’t need to be rebuilt, even though the platforms, tracks and signals will be changed or replaced for subway use.
It might cost millions extra to build slightly wider diameter tubes, and some people might complain about the wasted money, but I would think this is cheaper than having to spend billions later on rebuilding the tubes, or even having to build completely new subway tubes under the LRT tubes.
Granted, this is thinking about a situation that might occur beyond our lifetimes, but as you mention this kind of capital construction lasts for generations. We seem to forget that mistakes we make today with short-term thinking will need to be fixed (and paid for) by our children and grandchildren while muttering “geez what were they thinking back then … trying to save some construction dollars … ”
Steve: The tunnels that will be dug for Eglinton are big enough for LRT or subway. The larger issues will be found at the stations and turnback points.
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