With its unpleasant surprises, the Mount Royal tunnel constitutes “a great challenge” for the work of the Metropolitan Express Network (REM), and everything indicates that the electric train will not be able to travel through this section in the fall of 2023 as planned. weather.
Posted at 5:00 am
If the excavation phase is over, the workers still have a lot on their plate, you have seen Press last Wednesday, during a visit to take stock of the progress of the works on this centennial tunnel.
PDQ Infra, promoter of the project, and NouvLR, the consortium in charge of engineering and construction, do not confirm a postponement, but it seems a matter of time.
“It’s quite a challenge,” admits Jean-Philippe Pelletier, director of the Deux-Montagnes sector at CPDQ Infra, when asked about the schedule.
Trampling users hoping to board the REM from Ruisseau station in the Saint-Laurent neighborhood to get to Central Station will probably have to patiently continue to go through the trouble.
Commissioning of the tunnel in the fall of 2023 represents a major challenge. There are still exchanges with the technical teams and meetings with our project partners in the coming months.
Jean-Vincent Lacroix, CDPQ Infra spokesperson
It says that the Quebec woolen stockings subsidiary is on track for the commissioning of the Deux-Montagnes and Anse-à-l’Orme antennas by the end of 2024. As for the Montreal-Trudeau airport stretch, it will enter service after 2024.
Until then, the challenge is on the “execution” side, says Pelletier.
Approximately 90% of the drilling work (more than 60,000 holes were to be drilled in the tunnel) is complete. As a sign that work is progressing, an imposing steel structure has appeared at McGill Station, below McGill College Avenue.
“Six months ago, she wasn’t there,” says Mr. Pelletier.
far from over
Underground, workers are still completing the tunnel repair. The heavy machinery is still there. The lifting of the party wall of several kilometers to separate the two roads for security reasons has not yet been completed. Designed by a subcontractor, the wall segments continue to be delivered daily.
On the ground, where the rock is present, a concrete slab has been placed, but the installation of the railway tracks in the section of about five kilometers has not yet begun.
“It’s a complete transformation of the infrastructure,” argues Mr. Pelletier. It is of significant complexity. There were 60 trains a day before and with the REM we are talking about 500 trains a day. »
In addition, the engineer argues, NouvLR has only had free rein since May 2020. Only since then can the site managers work freely inside the tunnel, they say.
The presence of centuries-old dynamite, which caused an unexpected explosion in July 2020, slowed down the drilling work, which had to be carried out 50 meters away in an armored container. The exercises had to be modified accordingly. No employee could be within 500 meters of the drilling site.
In addition, the further deterioration of the tunnel due to the use of de-icing at McGill College and the absence of waterproofing membranes forced the developers to build a new vault, called the “umbrella vault”, underground for a distance of approximately 90 meters. between McGill Station and Central Station.
COVID-19 and its impact on absenteeism also slowed construction.
a surprise box
When embarking on repairing a tunnel as old as the one under Mount Royal, the unexpected was inevitable, especially in terms of drilling, says Jonathan Aubertin, a professor in the department of construction engineering at the École de Technologie supérieure (ETS ).
“With a virgin project we can carry out geological and geotechnical exploration, which gives us a good idea of what awaits us,” he said in an interview with Press. Of course, there are always surprises, but we control them a little more. In a project like this [le tunnel mont Royal], you will have uncertainty and unpleasant surprises. »
According to the expert, drilling work in the presence of “old explosives” such as in the tunnel that passes under Mount Royal is an “almost unique” situation in Quebec.
With the collaboration of William Leclerc, Press
- The REM network extends over 67 kilometers and includes 26 stations. The start-up of the South Shore branch is scheduled for this fall.
- 7 billion
- It is the invoiceforf the work of REM. The initial budget was 6,300 million.
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