REM construction – It is hard to miss, especially if you travel along Highway 40 in the West Island. Located at the back of the parking lot at the Fairview Pointe Claire mall, a gargantuan sized machine, an enormous yellow beam, seems to hang in the air. It is called a ‘launching gantry’ and its job is to put the pieces of the REM’s elevated structure together, one piece at a time – slowly but steadily building the foundation of the network.
It is one of two launching gantries, with the other assembling the structure between the TechnoparcMontréal in Ville Saint-Laurent to the midway point, which is at Fairview Pointe-Claire. From there the remaining section up to Sainte-Anne-de-Bellevue will be built. The beams are being installed between the columns that will support the almost 10-kilometre structure – and if you had the opportunity to get close enough to them, you would understand the magnitude of the work. Each beam is 105 metres long and will support up to 550 tons. It is a colossal undertaking and the first time launching gantries have ever been used in Quebec.
If you have not seen them in action, this is how it works: Prefabricated concrete segments, weighing in at approximately 50 tons each, are lifted up by the extremely powerful launching gantry. Then they are positioned by sliding them up against one another to form the deck where the REM’s rail cars will run. Because the segments are ‘launched’ one after the other, it explains why they are called ‘launching gantries’. It takes about two days to cover the 30 to 40 metre distance between two columns. Once a span is complete, the beam is moved forward to the next two columns where the process is repeated, ensuring things continue to move forward expeditiously.
REM Stages of construction of the elevated structure
Step 1 – Relocation of the elevated structure
Before construction begins, all of the public utilities (pipelines, buried electrical wires, etc.) along the REM route have to be moved to ensure their integrity remains intact. This painstaking process is carried out in close collaboration with the various suppliers such as Hydro-Québec and Énergir.
Step 2 – Pile Driving
The elevated structure’s columns and stations have to be firmly anchored in the ground. It is therefore necessary to drive foundation piles into the ground all along the route (14.5 km) to reinforce the ground that will bear the structures’ weight.
Ste 3 – Column construction
366 columns have to be built for the 14.5 km of elevated structure – that is an average of one column every 30 to 40 metres. As of last June, a hundred columns have been completed or are under construction on the West Island.
Step 4 – Prefabricated segment construction and delivery
Workers at BPDL’s plant in Saint-Eugène-de-Grantham, near Drummondville, are in the process of prefabricating 4,102 concrete segments.
Step 5 – Assembly using launching gantry
Everything is ready – launching gantries ‘Marie’ (after Marie Curie Street in the Technoparc) and ‘Anne’ (nickname for Sainte-Anne-de-Bellevue) are set into action! Installed between two columns, these gigantic beams hoist the prefabricated segments into the air and assemble them one after the other. (As mentioned above, it takes two days on average to erect one span to cover the 30 to 40 metres distance between two columns).
Step 6 – REM Station construction
This phase will begin later in 2022, once the elevated structure is complete. It will take another several months to build the wood and glass stations, to revitalize the sites (public and green spaces around the stations) and complete the access roads. To watch the gantries in action go to this link.