People heading to Montreal on both the Vaudreuil—Hudson and St-Jérôme train lines are facing delays.
Fanie Clément St-Pierre, spokeswoman for the AMT, says snow removal crews broke a switch in Montreal West last night, so trains need to take another route.
She says the problem should be fixed this morning, but she could not confirm at what time.
St-Pierre says delays are about 30 minutes per train.
CBC's Monique Lacombe has the latest. Follow her at @montrealdrive.