Tunneling in Canada

A Look at the Burgeoning Market North of the Border

Toronto skyline

The tunneling market in Canada is in the midst of a building boom with major projects underway or in the planning stages from coast to coast. Major centers of activity include Montreal, Toronto and Vancouver, with other works in Ottawa, Calgary and Edmonton among others.

These projects range from transit expansion and improvement projects to ease mobility in crowded urban centers, to water and wastewater infrastructure needed to support a growing population. Ontario alone is expected to add 4.2 million additional residents by 2043, according to a projection report by Statistics Canada, with the population of the Greater Toronto Area expected to exceed 10 million in that timeframe.
In the Greater Toronto Area, Metrolinx, the provincial agency created to improve the coordination and integration of all modes of transportation, is overseeing the planning and construction of several transit projects that involve tunneling: Eglinton Crosstown West Extension, Ontario Line, Scarborough Subway Extension, and Yonge North Subway Extension.“The current round of transportation projects was identified as part of the long-term planning by the provincial government, notably Metrolinx’s Big Move, which was

released in 2008,” said Jean Habimana, Global Director for Tunneling at Hatch, a global engineering consulting firm based in the Toronto area. “The plan incorporates regional transportation, whether it is surface infrastructure or subways, and integrates them across political and geographical boundaries throughout the area.”

“The high demand for tunneling in the Greater Toronto Area is largely driven by transit,” said Gary Kramer, senior vice president for Hatch. “The level of traffic congestion in the region has made the support for transit investment something that has broad appeal for the public and politicians alike.”

With the development of transit, water, wastewater and stormwater infrastructure investment is also needed. “The development of water infrastructure goes hand-in-hand with the development of the transit network,” said Marc Gelinas, Principal Project Engineer at Hatch. “The communities that surround Toronto are all expanding quite rapidly, and there is both a need to improve transportation and provide water, wastewater and stormwater services that allow new development.”

On the water infrastructure side, the City of Toronto is undertaking several ambitious multi-billion-dollar programs including a wet weather program to eliminate combined sewer overflows and reduce inflow and infiltration into sewers, and a stormwater infrastructure program to improve storm resiliency and reduce basement flooding. Included within these programs are the construction of a new outfall tunnel under Lake Ontario and three large CSOs tunnels in addition to various collection system and facility improvements.

“In Western Canada the expansion of transit, water and wastewater projects are expanding to service development in large growth centers, including communities within the Lower Mainland of British Columbia, Vancouver, Calgary and Edmonton,” said Derek Zoldy, Western Canada Regional Director, Tunnel Practice at Hatch.

In Calgary, the first phase of the Green Line LRT project is the largest LRT project to be constructed in the City of Calgary’s history. Phase 1 will connect the southeast to downtown and into the existing Red and Blue lines and four MAX BRT routes and will include the build of 13 stations, 18 km of LRT track, three park-and-ride facilities at Shepard, Douglas Glen and Lynnwood/Millican stations, 1 km of elevated track between 26 Avenue S.E. station and Ramsay/Inglewood station, 3 km of tunnel under Beltline and Downtown, four LRT bridge structures that span the Elbow River, Bow River, Deerfoot Trail and Blackfoot Trail, and one LRV maintenance and storage facility.

In Vancouver, Translink’s Broadway Subway Project is a 5.7 km extension of the Millennium Line, from VCC-Clark Station to Broadway and Arbutus. It will provide SkyTrain service to B.C.’s second-largest jobs center, world-class health services, an emerging innovation and research hub, and growing residential communities. The project includes 700 m of elevated track extending from VCC-Clark Station to a tunnel portal near Great Northern Way, 5 km of tunneled section below the Broadway Corridor from Great Northern Way to Arbutus Street, six underground stations, including a direct underground connection to the Canada Line at Cambie Street, and 99 B-Line bus service connection from Arbutus Street to the University of British Columbia. The new line construction is expected to be completed with project planned to open in 2026. On the water side, Metro Vancouver completed Project Definition of the Coquitlam Water Supply Project that is planned to double its capacity to withdraw water from Coquitlam Lake, the largest of its three drinking water sources. Planning is underway to determine the scope of work and design of a new water intake, a water supply tunnel, and water treatment facilities. Construction is expected to begin in the late 2020s, with completion targeted for the late 2030s.

Coquitlam Lake has served as a water source since the late 1890s. Today, it supplies about 370 million liters of water per day, or about one-third of the total drinking water demand of the Metro Vancouver’s 2.7 million residents.

Canada has a rich history in tunnel construction, with the first section of subway opening in Toronto in 1954, followed by Montreal in 1966. And while transit construction enjoys broad support, government agencies are not afraid to experiment when it comes to new tunneling methods or contracting strategies. Tunnel contracts run the range from design-bid-build and design-build, to design-build-finance and now progressive design-build models.

One recent innovation is the use of a large-bore tunnel for subway construction that allows bi-directional traffic in one tunnel vs. the typical twin-bore approach. “On the Scarborough Subway Extension we departed from traditional twin-bore method to a larger, single tunnel (10.7 m ID),” said Hossein Bidhendi, Tunnel Practice Regional Director at Hatch, which served as designer and technical advisor. “This will be the first large subway in Toronto and the largest in Canada.”

“The decision whether to use twin bores or single bores comes down to an analysis of cost, schedule and constructability,” added Dan Ifrim – Regional Director – Tunnel Methodologies at Hatch. “Single-tube subway construction becomes more feasible when you are able to eliminate cut-and-cover structures by using a larger bore.”

Below is look at some of the major works planned or in construction across Canada:

Greater Toronto Area

Ontario Line

Metrolinx awarded the $6 billion contract for the Ontario Line Southern Civil, Stations and Tunnel to Ontario Transit Group on Nov. 9, 2022. Ontario Transit Group comprises: Applicant Lead: Ferrovial Construction Canada Inc., VINCI Construction Grands Projects; Design Team: AECOM Canada Ltd., COWI North America Ltd., GHD Limited, SENER Group; Construction Team: Ferrovial Construction Canada Inc., Janin Atlas Inc.; Financial Advisor: Agentis Capital.

The design-build-finance project spans the southern portion of the Ontario Line, from Exhibition/Ontario Place to the Don Yard portal (west of the Don River). Works include 6 km of twin guideway (mostly in tunnels), one above-ground station to be integrated with the existing GO Transit Exhibition Station, two underground stations to be integrated with the existing TTC Osgoode and Queen subway stations and four new underground stations (King/Bathurst, Queen/Spadina, Moss Park, Corktown).

Major works are to commence in early 2023. The South Civil contract is anticipated to be completed in 2030.

Metrolinx is procuring the approximately $3 billion Ontario Line – North Elevated Guideway and Stations as well as Pape Tunnel and Underground Stations projects through Progressive Design-Build (RFQs Issued Nov. 17, 2022).It includes 10 km of twin track alignment (3 km in tunnel), one underground station integration with existing station (Pape of Line 2), one new underground station, 3 km of elevated guideway, five elevated stations, including two joint corridor elevated stations, two major bridges over the Don Valley and a grade separation.

The entire Ontario Line will be a 15.6-km rapid transit line running between the Ontario Science Centre and Exhibition/Ontario Place in Toronto, with 15 stations, including six interchange stations. The new line will provide more than 40 connections to other bus, streetcar, light-rail transit and regional rail services.

Scarborough Subway Extension

Metrolinx has awarded the Stations, Rail and Systems (SRS) contract portion of the Scarborough Subway Extension to Scarborough Transit Connect (Aecon Infrastructure Management Inc., FCC Construccion S.A. – applicant leads; Mott MacDonald Canada Limited – design prime team member; Aecon Infrastructure Management Inc., FCC Construccion S.A. – construction prime team members). The Scarborough SRS Project includes three new underground stations.

The $757.1 million Advanced Tunneling Contract (ATC) was awarded to Strabag in May 2021. The tunneling portion includes 7.8 km of extension. TBM began tunneling on Jan. 18, 2023, from the launch pit at Sheppard Avenue East and McGowan Road. At 10.7 m internal diameter, this will be the first subway tunnel in Toronto to contain two subway tracks operating in both directions. Hatch was the designer and Technical Advisor for the Advance Tunnel contract.

As tunneling 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 removed from the ground after completing its drive.

Yonge North Subway Extension

Metrolinx’s roughly $6 billion Yonge North Subway Extension (YNSE) will extend Line 1 (Yonge-University) roughly 8 km from Finch Station through to Vaughan, Markham and Richmond Hill with five new stations. It includes 6 km of twin 5.6-m ID running tunnels, constructed in shale and soft ground. The Yonge North Subway Extension will go into service after the Ontario Line is complete. It will be broken into two contracts: an Advanced Tunnel Contract (ATC) and a Systems, Rail, & Stations (SRS) contract. The planned date to begin the main construction of the YNSE is yet to be determined.

Eglinton Crosstown West Extension

Eglinton Crosstown West Extension will expand the Eglinton Crosstown light rail transit (LRT) line another 9.2 km west (6 km of tunnels), to Renforth Drive. Plans are also being explored to extend the line even further to Pearson International Airport. The project is underway by West End Connectors Construction (Aecon Infrastructure Management, Dragados Canada and Ghella Canada), which was awarded a $729 million contract in May 2021 and began tunneling April 2022. Completion is expected by 2025. Hatch was the designer and Technical Advisor for the Advance Tunnel contract.

Don River and Central Waterfront Wet Weather Flow System & Connected Projects

Part of Toronto’s $3 billion, 25-year CSO reduction program, the Don River and Central Waterfront projects comprise three major tunnels spanning 22 km. They are: Coxwell Bypass Tunnel, Taylor-Massey Creek Tunnel, and the Inner Harbour Tunnel.

The first stage is the Coxwell Bypass Tunnel, which comprises 10.5 km of 6.3-m diameter tunnel. The project includes five large shafts, 20 to 22 m in diameter and 50 to 56 m deep, and 11 drop shafts, 2 to 4 m in diameter and 50 m deep.

A $397 million design-bid-build contract was awarded to North Tunnel Constructors ULC, a joint venture team including Jay Dee Canada, Michels Canada and C&M McNally Tunnel Constructors. NTP was issued on Aug. 7, 2018, and the project is expected to be complete by 2024. The tunnel designers are Black & Veatch and R.V. Anderson Associates. The project was approximately 80 percent complete as of October 2022.

The Taylor-Massey Creek Tunnel is a 6-km long, 4.4-m diameter soft-ground tunnel that includes four shafts, 10.5 to 12 m in diameter and up to 60 m deep. Black & Veatch and R.V. Anderson Associates are the preliminary engineers. Design is expected to start in 2023.

The Inner Harbour Tunnel is split into two sections – East and West. Detailed design, being performed by Hatch and AECOM, is expected to be completed in April 2024. Inner Harbour West comprises 5.6 km of tunnel (6.3m ID) in Georgian Bay Shale Formation with three online storage shafts between 38 to 49 m deep and 15 to 30 m ID.

Ashbridges Bay Treatment Plant Outfall

The $300 million project for the City of Toronto, being built by Southland | Astaldi Joint Venture, is expected to be complete by July 2024. It comprises a 16-m diameter shaft, 85 m deep, 3.5 km of 8-m diameter TBM excavated tunnel with 7-m ID precast concrete segmental lining; and 50 each 1-m diameter risers from the tunnel (marine work). Shaft and tunnel excavation are complete. Hatch with Jacob & Baird served as consultant/designer.

Other wastewater tunnel projects in the Greater Toronto area include:

  • West Trunk Diversion, a project for the Region of Peel that includes 6 km of 15 to 45-m deep trunk sanitary sewer (1.2 to 2.4 m OD). Design is underway with construction anticipated from 2024-26. Hatch is the engineer.
  • Toronto Black Creek Tunnel, a project for the City of Toronto that includes microtunneling, EPB tunneling and large diameter CSO tanks. Construction RFP is expected for 2024. Black & Veatch is the engineer.
  • Toronto Midtown/Assignment 17-15, a project for the City of Toronto that includes 8.5 km of storm and sanitary sewers, and a new storm water tank and pumping station. It includes over 1.6 km of infrastructure to be installed by tunneling methods. Hatch is the engineer. Construction RFP is expected in 2023. project for the City of Toronto that includes 8.5 km of storm and sanitary sewer, and a new storm water tank and deep wet well. It includes 1.6 km of infrastructure to be installed by tunneling methods. Hatch is the engineer.



The Réseau express métropolitain (REM) is a new automated light metro network that includes 26 stations and 67 km of tracks. The REM is the largest public transit project undertaken in Québec in the last 50 years. The first trains are scheduled to depart in 2023 between Brossard and Central Station. The segments heading to Anse-à-l’Orme and Deux-Montagne stations are scheduled to begin service at the end of 2024. Finally, the segment to the Montréal Airport is scheduled to open in 2027. The REM involved the construction of a new 2.5 km soft ground tunnel near the city’s Trudeau International Airport (including under runways), and the upgrade of the 100-year-old Mount Royal Tunnel.

In Vancouver, major projects include the Millennium Line Broadway Extension, Annacis Wastewater Outfall, Transmountain Extension Pipeline and the Annacis Water Supply Tunnel.

Millennium Line Broadway Extension

The Broadway Subway Project is a 5.7-km extension of the Millennium Line, from VCC-Clark Station to Broadway and Arbutus. 700 m will be elevated, extending from VCC-Clark Station to a tunnel portal near Great Northern Way. Five km will be tunneled below the Broadway Corridor from Great Northern Way to Arbutus Street. Six underground stations will connect communities and the region, including a direct underground connection to the Canada Line at Cambie Street. Tunnel excavation began in October 2022. The new line will open in 2026. Broadway Subway Project Corp. (Acciona/Ghella) was awarded the $1.7 billion contract.

The upcoming Millennium Line UBC Extension runs includes tunnel and aerial guideway and five stations beginning from the end of the Broadway Extension.

Annacis Water Supply Tunnel

The Greater Vancouver Water District (Metro Vancouver) awarded a $288 million contract to Traylor-Aecon Group for the construction of the Annacis Water Supply Tunnel. a 2,350-m tunnel under the Fraser River that includes two deep vertical shafts on either side of the river. The anticipated completion date is 2027.

Annacis Island Waterwater Treatment Plant Outfall

Bessac, in partnership with Pomerleau Inc., was awarded the $184 million outfall contract by Metro Vancouver for the Annacis Wasterwater Outfall. The project consists of the construction of a new outfall pipeline from the Annacis Island Wastewater Treatment Plant (WTP) to the Fraser River. It includes: two 15 and 10 m diameter 40 m deep shafts inside the WTP; two segmental lining tunnels 4.20 m internal diameter (200 m and 580 m long); one river riser in the Fraser River; a 280-m long and 2.5 m diameter diffuser buried in the Fraser River bottom; and a new water control structure connected to the existing one. The construction started in 2019 and will last until 2024.

Coquitlam Main No. 4 Tunnel

The Greater Vancouver Water District (Metro Vancouver) is currently in the Preliminary Design Stage with Hatch and subconsultant WSP for a new 2.3 km long , 5 m diameter tunnel project to accommodate a 3.5 m diameter steel transmission main within the City of Coquitlam. The anticipated start of construction is in 2026.


Calgary Green Line – Downtown Section

The Green Line Phase 1 comprises 18 km of LRT track with 13 stations and 3 km of tunnel under Beltline and Downtown Calgary. The Green Line Board issued the RFP for Phase 1 to two short-listed proponent teams, Bow Transit Connectors (Barnard Constructors of Canada LP, Flatiron Constructors Canada Ltd, and WSP Canada Inc.) and City Link Partners (Aecon Infrastructure Management Inc., Dragados Canada Inc., Acciona Infrastructure Canada Inc., Parsons Inc., and AECOM Canada Ltd.). Following evaluation, one of the proponents will be selected in early 2023 as the Development Partner. The project is being procured as a design-build-finance with a development phase. Completion of in-market period will launch a 9 to 12-month Development Phase to allow for collaboration, design progression, and better understanding of risks and costs. Hatch is the Owner’s Engineer for the Green Line LRT project.

Comments are closed here.