TBM for Scarborough Subway Extension nearing completion

9 September 2021

Teams at Herrenknecht’s factory in Schwanau, Germany are progressing with the tunnel boring machine that will bore what will become Toronto’s biggest subway tunnel.

When quality control and testing is completed around the end of this month, the machine will be disassembled and shipped from Germany to arrive in Canada in early 2022. It will then be transported in parts by truck to the launch shaft at McCowan Road and Sheppard Avenue where crews will begin the process of re-assembly. Later in the spring, it will be lowered into the shaft to begin mining southbound under McCowan Road.

The tunnel alignment lies within the South Slope – an area of soft ground comprising mainly glacial till and interglacial granular, with a mix of sand, clay and small boulders. Advance rates of around 10m/day are anticipated.

With a diameter of 10.7m, the single tube tunnel will form part of the 7.8km Scarborough Subway Extension which will run underground for its entire length. It will also be the first subway project in Toronto to operate in both directions within a single tunnel.

Metrolinx – an agency of the Government of Ontario, under the Ministry of Transportation – is the project owner.