Soil conditions ‘hampering’ Scarborough subway extension tunnelling, Metrolinx CEO says

The Scarborough subway extension has been touted as one of the Ford government’s signature transit projects, but the president and CEO of Metrolinx says unexpected soil conditions are affecting tunnelling and it raises questions about the state of those efforts.

During his quarterly update in a public session to the Metrolinx board meeting on Thursday, Phil Verster provided a brief update on the $757-million advance tunnel contract being carried out by Strabag Inc.

“We’ve encountered soil conditions different than expected that have hampered the progress of the tunnel-boring machine,” he said.

“We have worked with Strabag on a technical solution and the schedule solution, and we hope to be giving more updates on that in the near future.”

The exact scope and timing of the soil issues, or the financial and scheduling impacts, wasn’t immediately clear. Verster didn’t mention the problem during his public update to the board in September and it hasn’t been shared on Metrolinx’s Scarborough subway extension updates website or X account recently.

Tunnelling of the three-stop, 7.8-kilometre extension began in January 2023 at McCowan Road and Sheppard Avenue East. The launch location is the future end site of the Scarborough subway extension. The tunnel-boring machine (TBM) is supposed to dig around 6.9 kilometres of the extension.

In January 2023, Metrolinx staff boasted the tunnel-boring machine as being roughly the length of three GO Transit train cars and how it would create a tunnel diameter the width of more than three TTC subway cars. Officials have said the machine would move around 10 to 15 metres daily. The whole journey was expected to take a little more than two years to complete.

A reply on the Scarborough subway extension X account dated Sept. 18 said the tunnel-boring machine travelled more than a kilometre and was south of Highway 401.

Officials said on social media in February that a public tracker to follow the tunnel-boring machine’s location and progress would be “launching shortly,” but a link to such a tracker couldn’t be found on the Metrolinx project’s website Friday morning.

CityNews contacted Metrolinx Friday morning to ask for additional information on the issues cited by Verster and to get a better understanding of the current state of tunnelling on the project. The media relations office sent a written statement late Friday afternoon after the publication of this story.

“Work has been paused at times for maintenance, including a planned stop before the TBM began its journey under Highway 401 and now another planned stop after it has reached the other side,” the statement said.

“The TBM has travelled over one kilometre and we are now working on plans to support its continued, steady operation as the project moves forward.

“Scheduling periods of thorough inspection and maintenance work allows crews to pre-emptively address wear and tear and optimize the overall functioning of the machine in relation to the ground it’s encountering.”

The statement referenced ongoing work elsewhere on the project and talked about future benefits, but answers to questions involving a link to the promised TBM tracker, specifics on soil issues, the difference in distance travelled versus the earlier projected timeframe for completion and potential budgetary impacts weren’t directly addressed.

“Updates on tunnelling and other project milestones will continue to be shared publicly through the project’s social media channels,” the statement said.

During an unrelated news conference on federal funding for new TTC Line 2 subway trains, CityNews asked Ontario Transportation Minister Prabmeet Sarkaria about the soil issues and how long those could delay tunnelling. He didn’t directly answer those questions, but praised the work being done and efforts to proceed.

“As we’re building and as we’re working through transit projects, we know it can be difficult, but we have a great team at Metrolinx that can get the solutions to those issues and problems and we’re working very closely,” Sarkaria said.

“We’re in the ground, we’re moving through it, and as the tunnel-boring machine continues to move we’ll continue to manage and we’ll continue to ensure a solution is put forward that works. I’m very confident in that.”

Despite the issues with tunnelling, officials pointed to progress elsewhere during Thursday’s meeting. At Kennedy station, they said extensive early work has carried on and foundational work has occurred on bringing extra electrical capacity as well as a new west ventilation fan plant to expand existing ventilation capacity.

Work on the TBM extraction site at Midland Avenue and Eglinton Avenue East as well as at the Lawrence and McCowan station site has been going on for several months.

Crews also demolished the Progress Avenue bridge over McCowan Road in September in preparation for building the future Scarborough Centre subway station.

The line is scheduled to open for service in 2030.

News of the issues facing part of the Scarborough subway extension comes at a time when there is a heightened interest and scrutiny on tunnelling in the Greater Toronto Area.

Premier Doug Ford announced in September his government was carrying out a feasibility study to explore a proposal for building a lengthy tunnel under Highway 401 to create extra lanes for vehicular traffic. An expert pegged the potential cost of building a tunnel through Toronto and potentially west toward Brampton at more than $50 billion.

Soil issues for tunnel projects aren’t an uncommon issue or consideration. As part of the early Yonge North subway extension work, Metrolinx officials said they’re doing a lot of work right now on figuring out soil conditions in an effort to prepare accordingly.

Meanwhile, excavation of the launch shaft for two tunnel-boring machines on the Ontario Line began earlier in November.