TBM Launch for SSE

Tunnelling begins on Scarborough Subway Extension

Diggy Scardust starts its tunnelling journey.

Jan 18, 2023

Tunnelling is officially underway on Scarborough’s 7.8-km subway extension.

The much-needed extension will bring subway service farther north into Scarborough and accommodate as many as 105,000 daily boardings.

Bringing the machine to life

Since arriving from Germany late last year, crews at the project’s launch shaft, located at Sheppard Avenue East and McCowan Road, have been busy preparing the excavation required to bring the tunnel boring machine (TBM) to life.

TBM Launch for SSE

A closer look at the TBM in the launch shaft as it starts to dig. (Metrolinx image)

Crews put numerous measures in place to safely and efficiently dig the deep pit, including building strong reinforced walls along the perimeter.

TBM Launch for SSE

A drone photo of the large excavation that was required for the TBM at the launch shaft site (Metrolinx photo)

The journey ahead

Over the next couple years, the TBM will travel 10 to 15 metres a day, making its way south from the launch shaft site towards Eglinton Avenue East and Midland Avenue. It will dig about 6.9 kilometres of the 7.8-kilometre tunnel that will be required to bring seamless subway service farther into Scarborough.

The remaining portion of the tunnel will be built by the contractor for the stations, rail and systems contract. At 10.7 metres wide, this will be the first subway tunnel in Toronto to contain two subway tracks operating in both directions.

As tunnelling gets underway, crews have already started work at the project’s extraction shaft site at Midland Avenue and Eglinton Avenue East, where the TBM will be extracted from the ground after completing its tunnelling journey.

Learn more about the extraction shaft.

TBM Launch for SSE

Site of the future extraction shaft where Diggy Scardust will re-emerge after tunnelling is complete (Metrolinx photo)

For the latest information on the Scarborough Subway Extension, visit the project website.

by Joshua Patel Metrolinx communications senior advisor, subway program