REM - Fact sheet

Planning completed in two years

It took only 24 months to complete the planning phase for the REM, including the financing structure, procurement and technical studies.

First commissioning five years after the start of construction

The first commissioning of the REM in July 2023, linking Brossard to downtown Montréal, took place only five years after groundbreaking in spring 2018.  

A tunnel boring machine named “Alice” was used to dig a 3.5-km-long tunnel to Montréal-Trudeau Airport. This was the first time  that this type of tunnel boring machine, which excavates the rock and assembles the tunnel segments at the same time, was used in Québec. This machine can move up to 1.70 metres per hour.

Two 105-metre launch beams, named “Anne” and “Marie,” were used to build the 13.5-km overhead structure in the West Island. The voussoirs, concrete bridge sections weighing 50 tonnes each, were prefabricated and then assembled piece by piece at the work site. It took two days to construct a span (about 40 metres) compared to three weeks using traditional methods.

At 72 metres underground, Édouard-Montpetit is the deepest station in Canada and the second deepest in North America, with its depth equivalent to a 20-storey building. 

To build it, 50,000 cubic metres of rock had to be excavated, which required 540 blasts, 100,000 kilograms of explosives, and two and a half years of work. The location of the work site in a densely built area  required the utmost precision. An exceptional control mechanism was put in place with about 20 seismographs spread out around the site.

The tunnel under Mount Royal, built in 1918, is a critical network infrastructure extending over 5 km. Major work was required to renovate and waterproof the structure, replace the tracks and electrical systems, and build two new stations. 

This major work was complicated by an unforeseen event at the start of construction in 2020, when drilling detonated a century-old explosive charge. Rigorous measures were quickly implemented, including a 585-metre exclusion zone in order to perform the drilling or excavation using remotely controlled robots.

McGill Station is known for its double arch between the Mount Royal Tunnel and Central Station that dates back to the early 20th century. The structure was experiencing infiltration in the concrete in the walls and corrosion on the steel structure, resulting from the use of surface de-icing salt over the past 60 years and no waterproofing membranes. To remedy this, the 92-metre-long structure was reinforced from the inside using the “umbrella method.” This method involves three steps: creating a temporary arch, demolishing the existing arch, and reinforcing the structure with steel arches.

A railway bridge had to be upgraded over the Rivière des Mille Îles to allow the REM to reach the North Shore. To offset the anticipated impact of the work on fish habitat, CDPQ Infra accepted a proposal from the Ministère de l’Environnement du Québec to create a spawning ground (fish breeding area) in the Rivière des Mille Îles. Biological monitoring in 2024 confirmed that use of the spawning ground exceeded expectations, with the presence of 11 fish species identified in and around the spawning ground, including walleye and lake sturgeon eggs, the two species targeted by the project.

The REM crosses a number of historic sites, including a cemetery in Pointe-Saint-Charles, the location of the remains of 6,000 Irish people who died from typhus shortly after arriving in Montréal in the 19th century. To minimize the impact on the site, the teams reviewed the design of the overhead structure in the area and decided build only one pillar. They also developed an unprecedented archaeological excavation technique that enabled them to discover bone fragments belonging to 14 persons and to learn more about their living conditions.

The REM project took place under the exceptional circumstances of the COVID-19 pandemic. This global crisis caused a number of hindrances, including the temporary shutdown of construction, procurement problems, limited mobility of skilled labour, and stringent health measures that made operations more complicated. However, the teams met the challenge by keeping delays to less than half a year.

Determined to offset all the GHG emissions associated with the construction of the REM, we participated in a tree planting program with the organization Earth Day and supported offset projects in Québec and elsewhere in Canada through the purchase of carbon credits. We track our progress annually in our Sustainability Report.