Preferred route for Toronto Metro Yonge extension 08 Apr 2021

TunnelTalk reporting

Plans for a fully-underground extension to the Yonge Subway in Toronto have been amended, following analysis of the costs, with part of the route to run at-grade in the preferred option of metro operator, Metrolinx. Two stations are also moved to the surface in order to reduce costs and maintain the financial viability of the project, which still includes a significant length of underground construction.

Fig 1. Three options for Yonge Subway extension
Fig 1. Three options for Yonge Subway extension

As originally proposed, the Yonge extension would have run fully-underground in new 7.6km twin running tunnels connecting five underground stations. Costs of this option were the most expensive of the alternatives analysed, at CAN$5 billion, significantly more than the now-preferred mixed surface-underground alignment which is estimated to cost $4.3 billion. This route runs underground from the existing Finch Station before surfacing as it approaches its northern terminus in the suburb of Richmond Hill (Fig 1).

A second fully-underground alternative comprising a large single-bore stacked excavation was also investigated with costs estimated at $4.5 billion.

Four stations are confirmed along the new route, including an underground station at Steeles Avenue, and two surface stations in Richmond Hill at Bridge and High Tech Road (Fig 2). These three locations are considered essential as they will “contribute a large portion of the ridership. This is particularly true of passengers who will access the subway by bus”, said Becca Nagorsky, Principal Sponsor of Planning and Development with Metrolinx.

Fig 2. Station at Steeles, Bridge and High Tech confirmed
Fig 2. Station at Steeles, Bridge and High Tech confirmed

The location of a fourth station is subject to negotiations between Metrolinx and the municipalities along the route as part of planning work. The metro operator is also exploring funding partnerships that could support a fifth station.

“Input from our partners has been vital to ensuring we understand the needs and aspirations of each municipality,” said Stephen Collins, Metrolinx Program Sponsor for the Yonge North Subway extension. “Given their role in leading the project before Metrolinx assumed responsibility, their knowledge and background was helpful in accelerating our understanding of the corridor.”

Analysis of the route will be continued in the Preliminary Design Business Case, which will also refine the design and delivery plans for the project.

The Yonge extension is one of four metro projects underway in Toronto with the other three in procurement for construction contractors. Preferred bidders were announced in March 2021 for construction of the 7.8km Scarborough Subway and 9.2km Eglinton Crosstown West metro extensions. Shortlisted contractors for construction of the southern part of the 15.5km Ontario Line were announced in January 2021.

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