One of the many myths about late Toronto Mayor Rob Ford is that he always chanted "Subways, subways, subways," whenever someone asked him about the transit future of Scarborough. Now, however, the Scarborough subway dream is turning into reality, according to recent news from Metrolinx.

Map of the "Scarborough Subway" project, image courtesy of Metrolinx

The provincial transit agency recently announced that its contractor has launched a tunnel-boring machine (or 'TBM') nicknamed Diggy Scardust from a site near Sheppard Avenue East and McCowan Road, marking a major milestone for the 'Scarborough Subway Extension' project. That project, one of four that the late mayor's brother, Ontario Premier Doug Ford, announced in April 2018, extends the TTC's Danforth Line 2 subway northeastward beyond the current Kennedy terminal, going three stations deeper into Toronto's eastern suburbs.

A closer look at the TBM in the launch shaft near Sheppard Avenue East and McCowan Road, as it starts to dig, image courtesy of Metrolinx

During the next two years, the TBM will travel 10 to 15 metres per day, moving southward from the launch-shaft site toward Eglinton Avenue East and Midland Avenue. It will dig about 6.9 kilometres of the 7.8-kilometre tunnel for the future subway. Unlike most of the recent Toronto transit projects with tunnels, which have had two TBMs drilling parallel twin shafts, the Scarborough subway extension project is a single-bore tunnel. Metrolinx explains that, "At 10.7 metres wide, this will be the first subway tunnel in Toronto to contain two subway tracks operating in both directions."

Crews have already started working at the project’s extraction shaft site, where they'll extract the TBM from the ground after it completes its tunnelling journey.

In May 2021, Metrolinx and its provincial partner Infrastructure Ontario (IO) awarded a fixed-price contract of $757.1 million to Strabag to design, build and finance the tunnel for the Scarborough Subway Extension project.

The Strabag team includes:

  • Construction Team: Strabag Inc.

  • Design Team: Arup Canada Inc., Brian Isherwood & Associates Ltd.

  • Financial Advisor: Strabag Inc.

A drone photo of the large excavation for the TBM at the launch shaft site, image courtesy of Metrolinx

The scope of work includes:

  • tunnelling;

  • designing and building launch and extraction shafts, tunnels and headwalls for emergency-exit buildings and stations;

  • supplying tunnel boring machines and installing segmental precast concrete tunnel liners; and

  • completing other activities necessary to build the tunnel (for example: relocating utilities, supporting shafts and headwalls, supplying temporary power, lighting, ventilation and drainage).

IO says that the team will deliver this contract "using a Design-Build-Finance (DBF) model. Key benefits of a DBF model include significant risk transfer to the private sector over the life of the project agreement, greater cost and schedule certainty and greater potential for design and construction efficiencies and innovation."

In November 2022, Metrolinx and IO selected Scarborough Transit Connect as the development partner (known as the “Dev Co”) to enter the development phase of the Stations, Rail and Systems (SRS) contract for the Scarborough Subway Extension project.

Site of the future extraction shaft near Eglinton Avenue East and Midland Avenue, where the TBM will re-emerge after completing tunnelling, image courtesy of Metrolinx

The Dev Co consortium consists of:

  • Applicant Leads: Aecon Infrastructure Management Inc., FCC Canada Ltd.

  • Design Prime Team Member: Mott MacDonald Canada Limited.

  • Construction Prime Team Members: Aecon Infrastructure Management Inc., FCC Canada Ltd.

The Dev Co scope of work includes:

  • designing and building three new underground stations and bus terminals at each station;

  • designing and building emergency-exit buildings, service buildings and traction-power substations;

  • installing, testing and commissioning all systems and equipment and interconnecting with TTC systems.

  • designing, supplying, installing, testing and commissioning all rail and track components and a pocket track east of Kennedy Station.

  • co-ordinatiing with Strabag on remaining work.

An August, 2022 drone shot looking east to work underway at Eglinton and Midland, image courtesy of Metrolinx

According to IO, "The project is being delivered using a Progressive Design-Build (PDB) model. Key features of a PDB model include the opportunity for greater collaboration between the project owner, the successful bidder, project partners, and communities."

Metrolinx claims that, when open, the subway extension will attract 105,000 daily boardings, including 52,000 by new transit users. It will connect as many as 38,000 daily passengers within a  ten-minute walking distance to transit. It will also improve access to jobs, with as many as 34,000 jobs within walking distance to transit. Metrolinx also says that, by extending the subway, it can reduce yearly greenhouse gas emissions by 10,000 tonnes.

The future subway will allow passengers to connect with GO Transit trains along the Stouffville line and TTC subway trains along Line 5 Eglinton (also known as the Eglinton Crosstown light rail transit line) and a future eastern leg of Line 4 Sheppard. And, they can transfer to and from TTC buses along multiple routes and GO and Durham Region Transit buses.

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UrbanToronto will continue to follow this project as it progresses. What do you think about the project? You can join in on the conversation in the associated Project Forum thread or leave a comment in the space provided on this page.

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