The cause of a train derailment that happened on August 11, 2017 has been verified.

A thermite weld failed when a Canadian Pacific Railway freight train was crossing a bridge over Roseau River, Near Dominion City, at 40 mph. The broken track caused the emergency train brakes to engage which forced 22 hopper cars off of the tracks. The TSB comments that nobody was hurt in this derailment. They add the train cars had been carrying corn, and though some product had been dislodged from the train cars, none ended up in the waterways.

Diagram of thermite failure (Photo credit: Government of Canada)

The investigation, finalized by The Transportation Safety Board of Canada (TSB) on July 24, 2018, reveals that no people, weather, or train equipment were at fault for this incident, and the insufficient weld is fully to blame.

Thermite welds typically join two pieces of rail together. The TSB notes in their report that a defect called “finning” can occasionally prevent rails from properly fusing with each other when molten metal leaks from the mould used in these welds.

The TSB indicates routine maintenance and surveillance of all railways are done weekly and problems like this should not happen.