The STM's new Azur trains will progressively resume service as of tomorrow after the transit corporation figured out what caused the problem that shut down part of the orange line for ten hours January 14.
The STM said it was normal wear and tear on the track and trains that was behind the problem causing part of the train to scrape against the rails and damaging it. The part in question -a contact shoe - comes into contact with the rail and electrifies it.
STM engineer François Chamberland said the interaction between the train and the tracks was caused when the worn part of the train scrapes against and gets caught in the worn down grooves of the track. Now they know that it was the track damaging the train and not vice versa.
Chamberland said they've already finished the soldering and molding work on the tracks where the incident occurs more often. The work on the rest of the tracks will be done over the next weeks and months.
The part on the train - which Chamberland said costs about $100 - will be replaced more often. They are usually replaced after every 60,000 km but Chamberland said they'll be replaced every 40 or 50 thousand km from now on.
On the new Azur trains, they'll also install a retaining mechanism to prevent as much scraping as possible between the train and the rail.
The STM said the costs of all this remain to be determined.