CALGARY, Alberta — A coupler failure led to a string of cars rolling uncontrolled in a Canadian Pacific yard in Calgary and hitting a group of stationary cars, causing a 22-car derailment, the Transportation Safety Board of Canada determined in its investigation of the January 2019 incident.
According to the TSB’s summary of the incident, a coupler knuckle failed while a string of 75 cars was in motion at CP’s Alyth Yard, leading to the uncontrolled movement by 56 cars. They were routed into the yard’s designated emergency track where they hit stationary, loaded hopper cars. Examination of the coupler found fatigue cracks in the area of the knuckle pin bore, leading to a safety advisor letter to Transport Canada and the Association of American Railroads.
The investigation report indicates the cars reached a speed of 13.5 mph by the time of the collision. Thirteen of the 14 hopper cars struck by the uncontrolled movement derailed, as did two cars on an adjacent track. Cars involved included four tank cars with residue of anhydrous ammonia and seven that had last contained molten sulphur; a hazardous material response determined that no dangerous materials had been spilled. No injuries were reported.
