Metrolinx Launches Tunneling Project on Scarborough Subway Extension

Written by Kyra Senese, Managing Editor
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A closer look at the TBM, Diggy Scardust, in the launch shaft as it begins to dig.

Metrolinx announced on Jan. 18 that tunneling for Scarborough's 4.8-mile subway expansion has begun.

The expansion will extend subway service farther north into Scarborough, with up to 105,000 daily boardings, the transit agency said in a release.

Since arriving from Germany late last year, Metrolinx said crews at the project’s launch shaft have been busy prepping the excavation necessary to bring the tunnel boring machine to life.

To dig the deep pit safely and effectively, crews implemented a number of procedures, including the construction of reinforced walls surrounding the perimeter, according to a release. 

During the next couple of years, the TBM will travel 33 to 49 feet a day, heading south from the launch shaft site, located at Sheppard Avenue East and McCowan Road, towards Eglinton Avenue East and Midland Avenue.

The machine will dig about 4.3 miles of the 4.8-mile tunnel needed to extend subway service farther into Scarborough, Metrolinx said. The contractor for the stations, rail, and systems contract will construct the remaining segment of the tunnel.

With a width of 35 feet, this will be Toronto’s first subway tunnel with two tracks operating in both directions, Metrolinx said. 

Crews have already begun work at the project’s extraction shaft location near Midland Avenue and Eglinton Avenue East, where the TBM will be retrieved once it has completed its tunneling trip.