Images from the scene show railcars lying in a zigzag formation metres from homes in the city. CN says no injuries were reported, nor were there any fires or "leaks" from the crash.
The derailment occurred almost 13 years to the day that an unattended Montreal, Maine & Atlantic train with 72 tank cars carrying crude oil rolled downhill into Lac-Mégantic, Que., on July 6, 2013, derailed and exploded in the downtown core, killing 47 people.
Residents of Repentigny, about 200 kilometres west of Lac-Mégantic, have many questions about how a train could derail when it was seemingly moving along a straight path, Dufour said. But they are also breathing "a huge sigh of relief" because no one was hurt.
CN Rail said three railcars that had previously contained diesel were empty at the time of the derailment, adding that they have been cleared from the scene.
The derailment occurred on the edge of a residential area, first responders acted quickly and all potentially hazardous materials have already been removed, Dufour said.
Crews clean up a derailed cargo train in Repentigny, Que., on Monday, July 6, 2026.Christopher Katsarov | The Canadian Press
CN teams have been removing the wagons one by one since late Sunday, Dufour said. The mayor believes some major streets could reopen as of Monday evening.
However, railway traffic will be closed off for a few more days, he said.
Dufour said repairs were being carried out two weeks ago on the stretch of the railroad where the train derailed, but he said it's too soon to say what caused the crash.
Hugo Fontaine, spokesperson for the Transportation Safety Board of Canada, said two investigators arrived at the scene of the derailment on Sunday to gather information and assess what happened.
The railway said it will provide additional information as it becomes available. "CN would like to apologize for the inconvenience resulting from this incident," railway spokesperson Michelle Hannan said.
Quebec Premier Christine Fréchette was asked about the derailment while holding a news conference in Longueuil, Que., Monday morning.
"I want to express my deepest sympathy for the residents living nearby. We’ve seen that for many of them, the derailment occurred very close to where they live," she said. "Of course, this does remind us of the Lac-Mégantic tragedy."
Fréchette took the opportunity to remind the federal government that it still hasn't built the long-promised rail bypass so that trains can skirt around Lac-Mégantic's downtown. She urged Ottawa to get moving on the project.
Crews clean up a derailed cargo train in Repentigny, Que., on Monday, July 6, 2026. Christopher Katsarov | The Canadian Press
This report by The Canadian Press was first published July 6, 2026.
