Rail fracture due to broken wheel led to April 2013 derailment


In its investigation report released today, the Transportation Safety Board of Canada (TSB) determined that a rail fracture caused by the impact of a broken wheel led to the derailment of a Canadian Pacific (CP) freight train near White River, Ontario. Three Class 111 tank cars released product. Two of the tank cars released petroleum crude oil and one released canola oil as a result of the accident. There were no injuries.

On 3 April 2013, a CP freight train, travelling from Edmonton, Alberta to Toronto, Ontario, experienced an undesired emergency brake application near White River. This occurs automatically when air pressure in a train’s braking system is interrupted anywhere along the train. Twenty-two cars derailed, nine of which were Class 111 tank cars. Seven of nine tank cars contained dangerous goods (petroleum crude oil – UN 1267). During the derailment, several cars rolled down an embankment. Two of the Class 111 tank cars released almost 102,000 litres of crude oil, while another Class 111 tank car released 18,000 litres of canola oil, which is not considered a dangerous good.

The investigation determined that there were no issues with respect to train handling and there were no track defects in the area of the derailment. Four days prior to the occurrence, a trackside wheel impact load detection system had recorded a wheel impact that was greater than the Association of American Railroads (AAR) wheel removal threshold, but company guidelines permitted the wheel to remain in service. Subsequently the wheel failed, fractured the rail, and caused the derailment. The top and bottom fittings on the dangerous goods tank cars did not adequately protect against product release during the derailment.

Following the occurrence, Transport Canada and the AAR began discussions on design improvements to Class 111 tank car bottom outlet valves to prevent product releases during a derailment. The AAR has since proposed design improvements to tank car bottom outlet valves.