Tunnelling begins on Scarborough Subway Extension

23 January 2023

Tunnelling is under way on Toronto’s Scarborough Subway Extension.

The Herrenknecht TBM, named Diggy Scardust, will dig about 6.9km of the 7.8km tunnel, advancing 10-15m a day.

The remaining portion of the tunnel will be built by the stations, rail and systems contractor, Scarborough Transit Connect, a consortium of Aecon Infrastructure Management, FCC Canada and Mott MacDonald Canada.

At 10.7m wide, the three-station Scarborough extension will be the first subway tunnel in Toronto to house two tracks operating in both directions. As tunnelling gets under way, crews have also started work at the project’s extraction shaft site.

Strabag was awarded the design, build and finance contract for the tunnel in September 2021.

The Scarborough Subway Extension is one of four priority subway projects in the Greater Toronto area, representing the largest subway expansion programme in Canadian history. The four projects, which also include the Ontario Line, the Yonge North Subway Extension and the Eglinton Crosstown West Extension, will add more than 40km of new subway service to the rapid transit network.