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City of Toronto report reveals more details
of "Scarborough subway" project

Update — Thursday, March 30, 9:10 a.m.: City Council approved proceeding with the next steps of the project Tuesday, March 28.

Scarborough subway logo2.pngThe City of Toronto has released its latest review of the “Scarborough subway” - the plan to extend the TTC’s Line 2 (Bloor - Danforth) subway 6 kilometres underground to Scarborough Centre.

Staff are continuing to recommend a line under the “McCowan Corridor”. According to the latest City report, the one-stop, express subway line will now cost $3.35 billion - considerably more than the original estimate of $2 billion. The new price tag includes $187 million to build a two-level bus terminal near Borough Drive and Triton Road in the Scarborough Centre development area.

Staff are recommending that the City and TTC work with Infrastructure Ontario to pursue a Design-Build-Finance procurement process to build the extension. According to Infrastructure Ontario, with this model, a consortium could use private-sector resources and expertise to finance and build the project. This process transfers project risks to the consortium, which is accountable for delivering the project on time and on budget.

Unfortunately, ths latest report reveals that the extension would only attract 2,300 new riders to the TTC. However the report also emphasizes the need to encourage development in Scarborough Centre. The report’s authors write:

“Transforming Scarborough Centre into a denser urban node will benefit the city in many ways, and could encourage greater development around Scarborough Centre.

“Overall, ensuring that the Scarborough Centre Station is integrated with the surrounding urban neighbourhood will maximize the benefits realized from the investment in the [Line 2 extension].”

The City’s report contains multiple secondary documents that detail other information about building this new line: the property that the City and TTC would need to build it, the “extra” subway structures, such as emergency exits and power substations that it would also build and the methods it would use for building all of it.

What happens next?
The City’s Executive Committee will consider the report during its meeting of Tuesday, March 7. City Council will review the report — and the Executive Committee’s actions — during its meeting on Tuesday, March 28. The Toronto Transit Commission will discuss the report during its meeting on Wednesday, March 22.

At each stage of this process, councillors or transit commissioners may move to approve, delete or amend any of the staff recommendations that could affect the scope of the project.

You can read the report and its various appendices here


“McCowan corridor”
City Council received an initial business base for the Scarborough Subway for its July 12 - 15, 2016 meeting. In that document, City staff recommended that the best option for extending Line 2 was under Eglinton Avenue East and Danforth and McCowan Roads, express from Kennedy Station to Scarborough Centre.

In the initial business case, staff also identified other corridor options, including tunnels under the current route of Line 3 (SRT or Scarborough rapid transit), Midland Avenue or Brimley Road.

route alternatives.jpg

However, staff ruled out options that required the TTC to close Line 3 during construction. Closing that line would result in Scarborough Centre being without rapid transit service for several years and presented no compelling advantage relative to the McCowan corridor. Not surprisingly, closing Line 3 would also present major impact on transit passengers. It would result in greater travel times, less convenient and reliable transit service and would likely reduce transit ridership in Scarborough Centre for the long term.

The July 2016 report also identified a cost of about $171 million to shut down Line 3 during construction of the Line 2 subway extension.

Subway extension alignments.jpg

“Brimley corridor”
During the July meeting, Council directed staff to continue to analyze an alignment under Eglinton Avenue East, Brimley Road and Triton, because it would allow the TTC to keep Line 3 operating during construction and cost less than the McCowan option. An express extension under Brimley would place the new Scarborough Centre Station under Progress Avenue (oriented towards the north-east, east of Brimley and west of Scarborough Town Centre.)

City staff have estimated the Brimley subway route would cost about $214 million less than the McCowan alignment. Most of the cost savings result from the alignment being shorter and from the future Scarborough Centre Station lying on a less constrained site. Nearby buildings do not surround the site and it has fewer roads or underground infrastructure. It is, essentially, an empty field and parking lot, not near any major destinations. However, significant growth in this area is not anticipated as it is near a successful industrial area that is incompatible with a mixed use urban area.


Line 3 corridor
In July 2016, Council also directed staff to re-assess and prepare a cost estimate for reusing the Line 3 corridor, with surface or above-ground track from a point south of Lawrence Avenue East. This proposal differs from the option that was part of the original business case, which would have placed a subway in the Line 3 corridor completely underground.

With this option, the line would extend through a tunnel east of Kennedy station, turn back to the west below a residential neighbourhood and meet the Line 3 corridor south of Lawrence East. The subway would emerge from the ground through a portal on the south side of Lawrence. North of Ellesmere Road; it would rise on an elevated structure to cross over the GO Transit’s Stouffville line. The rapid transit line would remain elevated along the current SRT corridor and into Scarborough station.

City staff have estimated that the cost for this option is $2.966 billion. But it would again require the TTC to close Line 3 during construction, because the portal and elevated track for the extension would need to occupy the same area as the current track. Accordingly, staff have removed the Line 3 corridor from the list of possible subway routes.


The Brimley route would attract about 1,300 new riders to the TTC, while the McCowan route would attract about 2,300. (Both ridership estimates fall far below original City / TTC projections of 4,000 new riders!)

Nevertheless, staff have concluded that the express subway under McCowan best supports the goal of developing Scarborough Centre as a vibrant urban node, because:

It better serves current destinations, population and employment on both sides of McCowan Road; It is close to the area which City Planning staff have dubbed “the McCowan Precinct”, where they’re planning for future growth and development pressure is greatest; and It supports plans to orient development around the McCowan Road corridor and, specifically, the Bushby / Town Centre Court gateway, including expanding the Scarborough Town Centre to this central area.

“The Big Bend
The Glen Andrew Community Association introduced yet another option. The community was concerned because the McCowan alignment presents a line that diverts slightly to the west off McCowan Road south of Ellesmere Road. While this provides a direct route to the Scarborough Town Centre, it also requires the TTC to tunnel under homes in the Glen Andrew neighbourhood. The original plans for the line also required the TTC to remove trees from the Frank Faubert Woodlot on the northwest corner of McCowan and Ellesmere to use as the tunnel-boring machine launch site.

This “Big Bend” route is similar to the McCowan alignment, but the subway remain under McCowan to just north of Ellesmere Road, where it would turn westward, with a station near the current Scarborough Centre Station. With this alignment the subway’s tail tracks - where the TTC could store trains overnight — would terminate in a vacant lot on the north-east quadrant of Brimley Road and Triton Road.


The community has suggested the Big Bend, if constructed with a large-diameter tunnel, would:

  1. Place a station at the current site of Scarborough Centre Station, without cut-and-cover construction or the decommissioning of Line 3;
  2. Avoid tunnelling under 10 residential properties on Stanwell Drive; and
  3. Avoid the necessity for a tunnel work site at Ellesmere / McCowan.

Designing and building a terminal subway station has significant complexities that require a width greater than the available space between the current Scarborough Centre Station and the Scarborough Town Centre. While TTC has undertaken significant work around this proposal, it has not identified any station concept - regardless of tunnel diameter or construction method - that it could build in the area between the mall and the Scarborough RT structure without having to close Line 3.

TTC staff have based two alternate alignments on the Big Bend concept by applying current design standards. They determined that both of these alignments would cause much greater impact to private residences; one would require tunnelling under 22 homes, while the other would require tunnelling under two multi-storey buildings (YMCA and a 300-unit condominium at 61 Town Centre Court). Either of these alignments would impact more property owners than the McCowan alignment.

Although staff did not prepare cost estimates for these Big Bend alignments, both were longer than the recommended McCowan alignment , which suggests that costs would also be higher.

The Big Bend concept would also require the TTC to remove Line 3 during construction and would affect more property owners than the preferred McCowan alignment. The TTC has also found a feasible alternative tunnel work site away from the Ellesmere / McCowan intersection. This has resulted in City and TTC staff not recommending the Big Bend idea for the subway extension.

Tunnel construction site
The July 2016 report to Council identified five potential tunnel work sites that each had significant community impact, so Council directed TTC staff to research alternatives. Accordingly, the TTC now proposes to locate the tunnel construction site near Highway 401.

Scarborough Centre bus terminal

Two-level bus terminal
According to the most recent staff report, a key component of the alignment is the station design, including all elements for the station to operate as a transit hub. One significant station element is a bus terminal. The bus terminal is integral to the success of the subway extension, since it provides a key transfer for many local and regional routes. A bus terminal that offers seamless transfers, with good connections, is essential to support existing riders, and can act as an incentive to attract new transit riders.

With this in mind, staff are recommending a new bus terminal to accommodate wider bus networks, including TTC, GO Transit, Durham Region Transit (DRT) and private inter-city carriers. Close to the Scarborough Town Centre and in the core of Scarborough Centre, the terminal will offer fast and easy connections to this regional destination. The terminal will likely require 34 bus bays, nine for articulated buses.

This large terminal provides:

  • TTC - 24 bays, including eight for the larger, articulated buses;
  • GO Transit - 6 bays;
  • Durham Region Transit - 1 bay for “artics”; and
  • inter-city buses - 3 bays.

The terminal would likely have two levels. The lower level would be in a wider Triton Road and accommodate 18 bus bays. An upper level off Borough Drive, would accommodate another 12 bays. Buses would also drop off or pick up passengers at four more bays on the east side of a new extension of Borough Drive. (The City was already planning this road extension and now will be building it as part of this project.)

A two-level terminal will reduce its overall surface area or “footprint” and protect future development potential near the subway station (Figure 6).

terminal site.jpg

The report reads that “City staff will continue to refine this concept to ensure the design supports growth and development in the area while potentially reducing cost. This conceptual design allows for a terminal that also supports the development of Scarborough Centre into a dense downtown with an urban street network that enables denser development and improved pedestrian connections.”

Development potential.jpg

Figures 7 and 8 illustrate how Scarborough Centre could develop around the subway station and bus terminal. This illustration represents a long-term vision and has not taken specific plans of current land owners into account. This illustration also assumes that a street network consistent with approved planning policy is implemented. The street grid that will best support the development of Scarborough Centre will be further articulated through the ongoing Scarborough Centre Transportation Master Plan.

The planners envision the intersection of McCowan Road and Bushby Drive / Town Centre Court as the gateway to the Centre. Today, McCowan Road is a challenging environment for pedestrians, including transit users. The road primarily for vehicles, with grade-separated intersections at Progress Avenue and several free-flow access ramps. To achieve the vision for Scarborough Centre, pedestrians must be able to access destinations, including the subway station, and they must feel safe walking along McCowan Road and crossing it.

Figure 8 shows how the bus terminal could transform McCowan Road.

McCowan development.jpg

City and TTC staff will continue to refine this concept to make sure the design supports growth and development in this area while reducing cost and impact to private properties. Landowners in the area surrounding the bus terminal, including Oxford Properties and the Government of Canada, will be key stakeholders in further refinements.

Street-Level Bus Terminal
The cost estimate that staff presented to Council in July resulted from plans for an at-grade bus terminal concept. This concept would span about 400 metres from Triton Road to Corporate Drive, between McCowan Road and Borough Drive (Figure 9).

at grade terminal.jpg

City staff no longer support this this terminal concept because it fails to deliver on several project objectives. It:

  1. Creates a physical barrier between the subway and the McCowan Precinct - where the City staff anticipate the greatest growth potential;
  2. Precludes a finer grain street grid for creating a vibrant urban node; and
  3. Eliminates prime development potential between Borough Drive and McCowan Road (both future main streets).

development - at-grade terminal.jpg

Figure 10 illustrates how this bus terminal would negatively impact development potential and create a barrier between the subway station and the McCowan Precinct, where future growth is planned and development pressure is the greatest.

The at-grade terminal design would prevent planners from significantly changing the street grid around McCowan Road by requiring developers to build any new east-west streets over the terminal. The terminal would also reinforce McCowan’s hostile environment for pedestrians, including transit users, by requiring more substantial free-flow ramps coming off McCowan and completely “sterilizing” the west side of the road.

Figure 11 illustrates how McCowan Road could look if an at-grade bus terminal was constructed.

at-grade-bus terminal illustration.jpg




The TTC has identified a cost for the McCowan alignment of $3.35 billion. The cost includes an at-grade bus terminal. The staff-recommended Triton Road bus terminal concept is estimated to cost $187 million more than the at-grade bus terminal.

In an article in the Toronto Star, City Hall reporter Jennifer Pagliaro writes that the tally of the total costs for one-stop subway extension may not even end at $3.35 billion.

Pagliaro explains,

“But that figure does not include nearly $600 million in additional costs that are detailed in the report but left out of that total.

“Currently $3.56 billion is dedicated to transit in Scarborough from three levels of government.

“The city’s chief planner Jennifer Keesmaat in conjunction with Mayor John Tory said by reducing the number of planned subway stops from three to one, a 17-stop LRT from Kennedy Station along Eglinton Ave. East to the University of Toronto Scarborough campus could be funded within that same $3.56 billion envelope. At that time, the six-kilometre subway extension was approved by council and estimated to cost $2 billion. “But in just one year, the cost of the subway has ballooned by 67 per cent, leaving the $1.6 billion LRT line Tory and staff promised short by $1.4 billion…

“The $3.35 billion estimate covers construction of the subway tunnel, new station, associated infrastructure, including a new bus terminal on Triton Rd. at the Scarborough Town Centre, and the decommissioning of the existing Scarborough RT.

“The report outlines several additional costs that are not included in that base number.

“The additional costs include $14 million for platform edge doors that line up with subway doors at the station — a safety feature that has not been implemented elsewhere in the system but council requested the TTC consider as part of future expansions.

“There is also an estimated $11 million for public realm improvements like wider sidewalks, plazas and street furniture.

“According to consultants hired by the city to review cost estimates, the city should also establish a reserve in case of changes to the scope of the project. While the city staff report said the TTC believes that $100 million is adequate for that reserve, the consultants recommended that fund be twice as much.

“Staff said the city must also build in a contingency for construction cost overruns and costs related to construction schedule delays — estimated, at what staff said are upset limits, of $115 million and $190 million respectively.

“The base cost also does not include an estimated $40 million needed for the construction financing model recommended by staff or an additional $15 million required for project advisory fees.

“Those additional costs, when you consider the higher-end estimates, total $585 million, putting the cost of the subway at $3.93 billion — leaving the subway $370 million short on funding.

“At that cost, the city would not have any funding for the LRT line and would also be short on the cost of the subway extension…

“In the report, staff also made a point of noting a large caveat on the $3.35 billion estimate. Because so little design work has been done to date, the estimate is only accurate with a very wide range and could be off by up to 50 per cent — what would put the base cost of the subway, without the above costs, at $5.02 billion.”

Property needs

By building a subway under the McCowan corrider, the City would permanently require all or part of 42 properties:

  1. Full property interest in one commercial property (for a traction power substation).
  2. Partial property interests in 35 private properties and 6 properties under City of Toronto, provincial or federal ownership.

The temporary tunnel construction site is on Scarborough Town Centre lands. The City and TTC will confirm temporary property requirements for construction during design.

Subway “extras”

Special trackwork”
The TTC uses the term “special trackwork” to describe track, other than standard parallel running tracks, that support the operation of the subway. A Line 2 extension would require this special trackwork in four locations:

  1. crossover tracks about midway along the length of the subway extension - near Lawrence Avenue East - to allow trains to switch tracks, to ‘cross over’ to the other directiond to address service reliability issues on the line or in emergency situations.
  2. crossover tracks just south of the subway platform at Scarborough Centre Station to enable eastbound trains to terminate and turn back westbound.
  3. crossover tracks north of the station to allow for potential future conditions where the time between trains is much shorter.
  4. tail tracks north of the station. These parallel tracks, together with the north crossover, provide the extra length to allow trains to operate safely at high speed into the station. They also provide a space to temporarily store trains overnight.

Station and tunnel ventilation
Ventilation shafts balance air pressure in the tunnels and the new station and provide an emergency exhaust and fresh air supply in the event of an underground fire. Ventilation fans also moderate high summer temperatures in the underground station.

Early studies recommend a mid-tunnel ventilation structure near Lawrence Avenue East. The structure will also be an emergency exit. These studies propose a surface-level footprint of about 1,000 square metres.

The TTC has already slated Kennedy Station is for upgrading its for fire ventilation system. It’s now proposing that some of this work will occur as part of the subway extension project. New fans at the east end of the station would ventilate the tunnel between Kennedy and the fire ventilation structure near Lawrence East.

Emergency-exit buildings
The structures are the surface element of stairways that extend from the tunnel to offer an emergency exit for passengers and an emergency access for firefighting crews. They often also provide a site for emergency ventilation and secondary power sources.

Each exit requires direct road access by a fire pumper truck and two parking spaces for TTC maintenance crews. The at-grade footprint of each Emergency Exit Building is about 30 square metres.

In accordance with national and TTC standards, the distance to an exit is never greater than 381 metres. The distance between emergency exits cannot exceed 762 metres.

Therefore, the subway extension requires eight emergency-exit buildings:

  • Eglinton Avenue East at Winter Avenue;
  • Danforth Road at Eglinton Avenue East;
  • Danforth Road at Savarin Street;
  • Danforth Road at Barrymore Road;
  • McCowan Road at Lawrence Avenue East;
  • McCowan Road at Meldazy Drive;
  • McCowan Road at Hurley Crescent; and
  • Corporate Drive at Progress Avenue.

The McCowan / Lawrence East building also includes a ventilation structure.

Traction Power Substations
Electric traction power operates the trains, lights, equipment and safety systems. Electrical substations connect the subway with Toronto Hydro’s power distribution grid. The substations contain transformers, switches and circuit panels to support the extension’s electrical requirements. To meet the traction power requirements for TTC’s subway system, substations are typically 2.0 to 2.5 kilometres apart. The TTC usually locates the electrical substations near subway stations, but, because this extension is 6.2 kilometres long, it requires three substations:

  • Danforth Road at Eglinton Avenue East;
  • McCowan Road at the “Gatineau Hydro Corridor” (across from St. Andrews Road); and
  • at Scarborough Centre Station.

The mid-tunnel traction power substations will also house communications and subway signaling equipment rooms. The substations would likely occupy and area of about 1,000 square metres.



As Torontonians have seen with other recent transit tunnelling projects, a tunnel boring machine would excavate or dig out the tunnel, remove the excavated material and place the initial tunnel lining in a continuous, highly automated process. The front end of the machine consists of a circular cutting face that excavates the soil and pulls it into its round shell. Recently, tunnelling in Toronto has used the “twin-bore” technique — two separate tunnels, one for each direction, with a six-metre diameter for each machine.

However, this project will probably require a large single-bore machine with a diameter of 10.7 metres to accommodate both set of tracks in a single tunnel. This approach also allows contractors to build the special trackwork in the tunnel rather than needing long sections of cut-and-cover construction with twin bore tunnelling. This approach significantly reduces the impact and cost of construction.

Cut-and-cover construction
For some sections of the future subway line, using a tunnel-boring machine is not practical or economical and cut-and-cover construction is necessary. Crews open the ground surface at a sufficient depth to build the subway tunnel structure. Vertical temporary walls to reduce the volume of material for removal and to protect nearby areas usually support the sides of the excavation. The walls require cross -bracing or tiebacks for support.

Once the contractors have finished digging, they build the structure from the bottom to the top. Once they’ve completed the structure construction, they backfill the remaining excavation is and restore the surface. When the construction takes place under a roadway, crews usually install decking to allow vehciles to travle along the road, while the construction occurs below.

For this project, expect cut-and-cover construction:

  • at the station - the large spans (station platform widths), relatively short lengths and complicated spatial arrangements normally prevent economical tunnelling;
  • at emergency exits and and vent structures; and
  • at the shallow section immediately east of Kennedy Station.

Launch and extraction shafts and tunnel-construction sites
Tunnel construction would begin at the north end of the alignment to complete tunnelling to the south side of the station site as quickly as possible. This allows the contractors to build the station at the same time as tunnel construction.

Crews would launch the tunnel-boring machine in an area north of the station and south of Highway 401. This requires a very large excavation, roughly 90 metres long and 20 metres wide. The machine would proceed southward, past the station site. The contractors would then establish the primary tunnel work site immediately south of the station box and the Line 2 guideway.

The tunnel work site is a temporary construction site where many key functions of the subway construction take place, including point-of-entry for the tunnel liners and tracks, and removing discharged tunnel soil. Trucks bring the tunnel liners to this site and take excavated soil away. This work site requires an area of about 10,000 square metres (1 hectare) and the contractors will use this site for most of the construction.

tunnel work sites.jpg

The tunnel-boring machine launch site must act as a temporary work site until the machine reaches the primary work site, south of the station. As a result, this area will be subject to the greatest level of impact during construction.

The current plan is to extract the tunnel boring machine through a shaft on the south side of Eglinton Avenue East near Town Haven Place. Crews would dismantle the machine in the tunnel and take it out in sections, requiring a significantly smaller shaft. A section of cut-and-cover construction immediately east of Kennedy Station will incorporate the extraction shaft.

Two-phase construction of the bus terminal
The current Line 3 structure is an impediment to finishing the new bus terminal. For this reason, contractors must build and open the terminal in two separate phases:

  • Phase 1: Contractors will complete that part of the bus terminal that they can complete with the Line 3 structure in place before the subway opens. Buses will use the current bus terminal during this time. However, construction activities around the station area will block Triton Road west of McCowan - potentially for long periods - and most of the buses now using the Scarborough Centre bus terminal will have to enter and exit terminal along the Triton Road access on the Brimley Road side of the Scarborough Town Centre.
  • Phase 2: Once the subway is open, Line 3 and current bus terminal will close and buses can use that part of the new terminal that the contractors build was constructed during Phase 1. Transit agencies will have to develop an interim plan for buses to serve the new subway station, using the partly completed terminal as much as possible, with temporary bus stops in the southbound bus-only right-turn lane on McCowan Road at the station entrance or on the newly build Borough Drive extension. Crews will demolish Line 3 and the current Scarborough Centre station and bus terminal will be demolished and build the rest of the new new bus terminal. The entire new bus terminal will likely be available 1.5-to-2 years after the subway opens.