The green line finally restarted on Tuesday morning, after a long interruption in the middle of the rush hour on Monday, the deterioration of the concrete in the vault of the tunnel between Berri-UQAM and Saint-Laurent having been deemed “superficial”. Beyond the impacts, however, the event demonstrates that the Montreal metro is coming to a pivotal moment in terms of maintenance.

“We are in the second life cycle of the infrastructure. The Saint-Laurent metro was built when it opened in 1967, so you have to be aware that we have aging infrastructure. We must continue our maintenance efforts,” said the director general of the Société de transport de Montréal (STM), Marie-Claude Léonard, in an interview with La Presse.

In a press release on Tuesday, the Company announced the reopening of the green line around 5 a.m., nearly 12 hours after the total interruption between the Frontenac and Lionel-Groulx stations, a section which serves approximately 150,000 people per day. It was a water leak that detected cracks in the vault of the tunnel between the Berri-UQAM and Saint-Laurent stations.

“After more than six hours of auscultation, hammering and observation, the degradation of the concrete is superficial and the integrity of the vault is not in question”, indicated the STM on Tuesday, ensuring that a team of experts carried out a rigorous assessment of the situation.

Ms Léonard says the emergency work, held overnight from Monday to Tuesday, helped “bring down the concrete that might have fallen by vibration onto the track”. “There is no curve to the armature. The structure is intact and everything is safe, so we reopened. Reopening is never a decision taken lightly,” she said.

However, various preventive works will still have to take place above the tunnel. A metal fence will also be “installed over the next few nights to give us time to carry out work,” says the STM. “Permanent works” will then be undertaken. “We will go to tender for the reconstruction of the surface of the vault as new. This process can take several months,” spokesperson Justine Lord-Dufour confirmed.

Marie-Claude Léonard specifies that “various asset maintenance programs” allow her group to hold “frequent evaluations” of the metro. A “subway tunnel vault structure inspection plan” had already been initiated in recent years, and will continue. “Everything is in place for us to prevent it, but we can never say that it will not happen again”, evokes the DG.

For Pierre Barrieau, an expert in transport planning at the University of Montreal, it is important to understand that the metro is coming at a pivotal moment. “We are entering a long period of permanent work for the entire network. In the medium term, this may mean more and more frequent closings, a longer night period, or an hour or two less of service every day to allow for longer work cycles,” he reasons.

“Already, the metro had a significant accumulated maintenance deficit, but now we are coming to large investments that are coming in the maintenance of assets,” continues Mr. Barrieau.

The latter cites the example of the New York subway, “which entered a period of great decline at the turn of the 1960s because its equipment was reaching the end of its useful life, and the City did not have the financial means. to carry out all the work required”. “We had seen a lot more breakdowns and all kinds of problems then. Maintenance is really fundamental,” he illustrates.

At the start of the day, Tuesday, users were divided. “It worries my wife since she takes the subway every day to go to work. It is certain that she was concerned this morning, ”says Montrealer Marc Biron, who was going to an appointment when La Presse arrested him.

“We must not forget that the metro was built in the late 60s. It is cement, and we have four seasons, a lot of rain, a lot of frost. I think it’s normal what happens. You just have to manage it well, ”continues the 69-year-old man, who will benefit from free public transport from July, a promise fulfilled by the Plante administration.

“I already have my pass ready for this.” The metro is still the best option for getting around town, “said the sixty-something with a smile.

Other users met by La Presse also claim to have certain concerns. “We especially wonder if there is more important work to come,” said one of them, for example, as he entered the metro at Berri-UQAM.