Tunnelling underway on Metrolinx’s Scarborough’s Subway Extension.

Jan. 19, 2023

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

Related To: Metrolinx

A closer look at the TBM in the launch shaft as it starts to dig.

Tunnelling is officially underway on Metrolinx’s 7.8-km (4.85-mile) Scarborough 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.

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

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

The journey ahead

Over the next couple years, the TBM, named Diggy Scardust, will travel 10 to 15 meters (33 to 49 feet) daily, making its way south from the launch shaft site towards Eglinton Avenue East and Midland Avenue. It will dig about 6.9 kilometers (4.3 miles) of the 7.8-km (4.85-mile) 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 meters (35.1 feet) 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.