Twenty of the 71 Azur trains of the Société de transport de Montréal (STM) are currently at a standstill due to “premature wear” of the wheel bearings, La Presse has learned. This forced pause does not affect the service at the moment, but the carrier cannot assure that no impact will be felt in the longer term.

“We already have mitigation plans ready should we ever have an impact on service. That said, we currently have room for manoeuvre. Not only have we kept more MR-73 [older models] trains, but ridership also remains at around 70% while delivering the same volume of service. However, I cannot tell you that zero risk does not exist, “admitted the company’s general manager, Marie-Claude Léonard, in an interview with La Presse.

His group says it noticed as early as 2019 an “anomaly” in the rolling stock of trains – the equivalent of what is often called a bearing for cars – i.e. the part fixing the wheel to the vehicle and allowing it to turn. Essentially, a construction fault allows electrical current to pass through the bearings, subsequently creating arcs that destroy them.

STM engineers had first found a “temporary solution” at the time by removing the ground braids protecting the electrical cables, in order to avoid premature wear of the parts.

In the fall of 2022, a “permanent” and more durable solution was finally implemented to correct the problem. This involves installing on each of the hubs – the central part of the train wheel – a set of conductive crowns which redirect the electric current elsewhere than on the rolling stock, for example towards the rail which recovers the current by the following. It is the French multinational Alstom which has set up this system.

According to our information, all Azur trains are affected by this “anomaly” on the rolling stock. They will therefore eventually have to go through this upgrade, starting with the twenty or so trains that have just been taken out of service. “Depending on the protocol, we will withdraw the trains and put others in operation. We’re still going to stay at around 20 trains,” says Leonard.

“Currently, we are taking out a few more trains than we are putting them back into operation”, admits the DG, however, who wants to “double the rate” of replacing hubs in the coming weeks, in order to avoid any cuts in services.

For now, the STM is not yet able to determine how much it will cost to upgrade the hubs under its Azur trains. The whole thing would be “under analysis”. The company has 71 of these trains, mostly in service on the Orange and Green lines, as well as 40 MR-63 trains, which are seen mostly on the Blue and Yellow lines.

To date, the situation has caused “no impact on the service” provided in the metro, assures Marie-Claude Léonard. “We follow this issue on a daily basis, we are very rigorous. If there were to be any impacts on the service, we would inform our customers at least two weeks in advance,” she insists.

Saying she is optimistic in the short term, the general manager admits that nothing is guaranteed. “I can’t tell you never,” she agrees of a possible drop in service, should the mechanical issues persist.

The other challenge is supply chains, most of which have been severely disrupted in the midst of the COVID-19 pandemic. According to our information, some replacement parts for the trains are not yet available.

“The required documents, we have them, however assures Marie-Claude Léonard. At the same time, everyone is aware of the issue of global supply. The good news is that we have secured a good number of parts, which tells us that we should be able to double the replacement rate,” she reiterates.

This is not the first time that mechanical problems have been spotted on Azur trains. At the start of 2017, the STM had been forced to withdraw several trains from its network after shoes, pieces of equipment located under the body of the cars used to ensure the power supply, had been damaged on eight Azur car trains and one train of cars MR-73.

At the time, this major event caused a complete interruption of service for 10 hours on part of the orange line of the metro, frustrating users and elected municipal officials. Damage had been caused in particular by defective shoes to the signaling equipment at Du Collège station.