Teams now will spend the next several months detailing how they would design and build the extension of Bloor-Danforth Line 2 subway about 4.8 miles to a new terminus in Scarborough, an outlying district in the city.  Proposals will cover how three stations and emergency exit buildings, fitting the subway tunnel with track and signals, and installing and commissioning systems required for operations.

Officials from Infrastructure Ontario and Metrolinx, the regional transportation authority, are set to select the winning bidder by next fall. The construction contract will be awarded in mid-2024.

At that point, the agencies will enter a “development phase” with that team and reach final agreement on a “detailed design and a negotiated price,” they said in a press statement.

The Scarborough extension is part of a $23.1 billion subway expansion program for greater Toronto and Hamilton that Ontario announced in April 2019. Last year, Canada's federal government committed to fund 40% of eligible costs, more than $8,7 billion, for the extension and three other priority regional rail projects 

The Scarborough project has been one of the longest and most hotly debated mass transit projects in Toronto history, with extension plans eyed for 15 years, said Matti Siemiatycki, an associate professor in urban planning at the University of Toronto. Along the way there were various stops and starts as plans were proposed and rejected, with a shift from less expensive light rail to a more costly subway line.

“This has been a long and winding road for the Scarborough Subway Extension,” Siemiatycki said.

One key issue has been the high cost of building subway service – and a nearly five mile long tunnel – through Scarborough, which has the density of a suburb. A Metrolinx study in 2013 found that to justify the extra cost of building the subway line, 20,000 new condo units would have to be developed along the route, according to the Toronto Star. 

Also evolving is the approach taken by city and provincial transit officials to bidding out project work.

There have been a number of large public-private-partnership (P3) transit projects in Canada that have struggled with cost overruns and other issues, causing some major contractors to pull back, Siemiatycki said.

Infrastructure Ontario and Metrolinx have responded by breaking down the Scarborough project into two more manageable parts. The tunnel boring contract was awarded last year to Austrian contractor Strabag, with work already underway.

“That has been the innovation here – the tunneling in some of these P3 jobs has been a place of great risk, with all sorts of variables and change orders and conflicts,” he said.

Moving Forward

Provincial and regional transit officials also are using the Progressive Design-Build delivery model for the subway, says Ian McConachie, a spokesperson for Infrastructure Ontario.

Instead of coming to the project with its own design plans already hammered out, the winning bidder will work with transit agencies as well as other key stakeholders in a “development phase” for the final design and contract terms.

“Recent market engagements have indicated that the Progressive Design-Build procurement model will attract the highest interest from the market, leading to a more competitive procurement,” McConachie said in an email.

The team supporting Dragados includes AECOM Canada as lead designer.

The Kiewit/SNC-Lavalin venture, KSX Integrated Design-Builders, features both companies as project leads sharing design and construction duties.

The team headed by Toronto-based Aecon, Scarborough Transit Connect, includes Mott MacDonald Canada leading design and Aecon unit Aecon Infrastructure Management and FCC Construction heading the buildout..