The Scarborough subway expansion project will involve a 7.8km-long extension of TTC’s line two Bloor-Danforth subway. Credit: Metrolinx.
The subway extension project will add three new stations. Credit: Metrolinx.
The Scarborough subway expansion project is expected to be completed by 2029 or 2030. Credit: Metrolinx.

The Scarborough subway extension project is a proposed 7.8km-long extension of the Toronto Transit Commission’s (TTC) line two Bloor-Danforth subway in Toronto, Ontario, Canada.

Assigned to the government-owned integrated transit systems (ITS) planner Metrolinx and Infrastructure Ontario (IO), the subway extension will replace the older line three, also known as the Scarborough Rapid Transit (RT) line.

The extension project is among the four priority transit projects of the Province of Ontario in the Greater Toronto and Hamilton area. The other three projects include the Eglinton Crosstown west extension, the Ontario line project, and the Yonge North subway extension. The Scarborough plan is estimated to involve an investment of approximately C$5.5bn ($4.11bn).

The original environmental assessment of the project was released in 2017 and an addendum to the report was updated in August 2020. The project is expected to start in the second quarter of 2021, with its completion scheduled for 2029 or 2030.

Scarborough subway extension details and construction works

The subway expansion project will involve the extension of line two Bloor-Danforth subway from the existing north-east Kennedy station to McCowan Road and Sheppard Avenue. Tunnelling works will be undertaken throughout the length of the alignment. Eight emergency exits will be built to the street level along the line.

Other construction works of the project will include traction power substations, emergency exit buildings and upgrades at Kennedy station.

Scarborough subway extension stations

The line extension will involve the construction of three new stations at Lawrence Avenue and McCowan Road, Scarborough Centre and a terminal station to be built at McCowan Road and Sheppard Avenue.

The stop at Scarborough centre will be located towards the east of the existing Scarborough rapid transit (RT) stop and next to Scarborough Town centre. Passengers will have further travel options through the connections offered by the new station to TTC, GO bus services and Durham region transit bus services.

The terminal station will offer a new and faster transit option to users travelling to and from northern Scarborough. It will also have the option to connect to the future Sheppard Subway (Line 4) extension.

All the stations in the transit subway system expansion project will have vent shafts and traction power substations (TPSS).

Early works

Initial works will mainly include tunnelling along the section. The existing utilities such as internet, telephone, water and natural gas will be relocated to reduce service disruptions during the construction phase. Ongoing preparatory works include surveying, geotechnical drilling investigations and utility relocations.

Ridership and benefits

The extension is estimated to have 105,000 daily commuters, 52,000 of which are expected to be new.

The project will provide increased connections to new jobs across the city, with a projected 34,000 jobs within walking distance from the new stations by 2041.

Travel times will be reduced and access to jobs, schools and other important destinations across the city will be improved.

Contractors involved

A team led by Austrian construction company Strabag was selected as the first negotiations proponent (FNP) to design, build and finance the tunnels for the extension in March 2021.

The team also includes design companies Arup Canada and Brian Isherwood & Associates and will participate in negotiations with Infrastructure Ontario (IO) and Metrolinx to finalise the project implementation details.

A joint venture (JV) with engineering services and construction companies Stantec and Jacobs, 360 Transit Alliance was chosen to lead the programme control services contract for Ontario’s four priority transit projects, including the subway extension project in December 2020. The contractual scope includes the provision of scheduling, risk management and quality assurance services.

Infrastructure Ontario and Metrolinx awarded the technical advisory services agreement to the OneT+ JV for the project in June 2020. The JV partners include Gannett Fleming Canada and IBI Group.

Lakeland Consulting is the fairness advisor while McCarthy Tetrault is the legal advisor for the project.