The Transportation Safety Board of Canada (TSB) is calling on Transport Canada to introduce enhanced analysis of railcar wheels after a 2023 derailment in central Alberta. Investigators found that a shattered wheel rim caused the wreck, and said tracking deterioration over time could help identify failing wheels before they break.

On April 5, 2023, a CN freight train was travelling west on the Wainwright Subdivision when a train-initiated brake brought it to a stop. During an inspection, the conductor found 18 derailed cars. Grain had spilled from railcars that overturned and were breached. No injuries were reported.

The TSB investigation determined that repeated impacts damaged a wheel and led to a series of fractures along the track, causing the derailment. Regular wheel inspections had been conducted in line with TSB standards, but they did not identify a problem with the wheel.

Railways use wheel impact load detector (WILD) data to monitor wheel condition, measure impact forces and flag problematic wheels. The data is assessed independently, without evaluating trends over time or the rate of deterioration. The TSB says rapidly worsening wheels can be missed among other impact conditions and may fail before they are removed.

The wheel was scheduled for removal in Edmonton after its impact readings showed it did not meet CN’s WILD standards. It failed before reaching the city. The TSB wants Transport Canada to implement analytical methods that can track trends and the rate at which wheels deteriorate.

The agency also raised a safety concern about the wheel’s age. It was manufactured in 1991, before steel cleanliness standards were introduced in 2003. Wheels made before 2003 are more prone to shattering and rim failure.

Based on reporting by CTV News Edmonton.