Federal agency links Quebec train derailment in December to temperature swings

MONTREAL — The Transportation Safety Board of Canada says it could not determine the exact cause of a freight train derailment in northern Quebec last December.

The agency says the derailment likely happened after a rail broke under stress from sharp temperature swings and the earlier passage of another train with a wheel defect.

The train was carrying iron ore and derailed on Dec. 28 about 60 kilometres north of Sept-Îles, on Quebec’s North Shore, after an automatic emergency brake was triggered.

Twenty-nine railcars and one locomotive derailed, but no one was injured, and most of the spilled iron ore did not reach the frozen surface of the nearby Nipissis river.

The report says the rail line recorded 47 broken-rail incidents in 2025, with more than half occurring in January and December.

The report says the track installed in 2022 had been inspected just three days before the derailment, with no defects detected.

This report by The Canadian Press was first published July 22, 2026.

Pierre Saint-Arnaud, The Canadian Press