a large machine tearing away at a building.

Tunnel contract finalized for Scarborough Subway Extension

The Scarborough Subway Extension is picking up pace and long-discussed plans are becoming a reality.

May 25, 2021

The three-stop Scarborough Subway Extension is moving quickly toward breaking ground on major construction now that a contract has been finalized with Strabag for the project’s tunnelling work.

The 7.8-kilometre subway extension will bring reliable and seamless transit further into Scarborough and, once complete, will help reduce gridlock by attracting more than 100,000 riders each day. It’s a key pillar of the Province’s historic $28.5 billion subway expansion program, which also includes the Ontario Line, the Yonge North Subway Extension, and the Eglinton Crosstown West Extension. Together, these projects will add more than 40 kilometres of new subway service to the rapid transit network.


To deliver the project as quickly as possible for the people of Scarborough, Metrolinx and Infrastructure Ontario have split up the delivery of the project into two contracts – the advanced tunnel contract and a stations, railway and systems contract.

This builds on the progress Metrolinx and Infrastructure Ontario made earlier this year when they identified Strabag as the team they were in final negotiations with on the advanced tunnel contract. As part of this contract, Strabag will be responsible for designing and constructing the tunnel for the Scarborough Subway Extension. This includes designing and building the launch and extraction shafts and supplying the tunnel boring machine. The community will even have a chance to weigh in on a name for the tunnel boring machine later this year.

Strabag, as a consortium, is made up of a mix of international and local companies who have extensive experience working on other major tunnelling projects in Canada and around the world. The companies that make up Strabag include the following:

  • Applicant Lead: Strabag AG
  • Construction Team: Strabag Inc.
  • Design Team: Arup Canada Inc., Brian Isherwood & Associates Ltd.
  • Financial Advisor: Strabag Inc.

Once they were first identified First Negotiations Proponent, Metrolinx and Infrastructure Ontario wasted no time in getting agreements in place with Strabag to ensure that they could carry out early works at the launch shaft site, located at the northeast corner of Sheppard and McCowan. This site is where the tunnel boring machine will descend into the ground to begin the tunnelling process. Since April, Strabag’s crews have disconnected utilities, began clearing structures and set up office trailers to prepare for construction.

a large machine tearing away at a building.

Preparatory works underway at the launch shaft site, located at the northeast corner of Sheppard and McCowan (Metrolinx photo)

Now that all aspects of the advanced tunnel contract have been finalized, work continues at the launch shaft site to prepare for the massive excavation required before the arrival of the tunnel boring machine early next year.

As work progresses quickly, Metrolinx will continue to keep the community informed about progress and what to expect during every phase of construction. A virtual townhall is being hosted on May 31 to provide the latest project updates and answer any questions from the community. You can find more details about this session and watch previous virtual sessions by clicking here.

by Joshua Patel Metrolinx communications senior advisor, subway program