In its investigation report (R13E0142) released today, the Transportation Safety Board of Canada (TSB) determined that numerous rail fractures led to the October 2013 derailment and fire involving a Canadian National (CN) train in Gainford, Alberta.
On 19 October 2013, a CN freight train, travelling from Edmonton, Alberta to Vancouver, British Columbia, derailed 13 cars, including 4 DOT 111 tank cars containing petroleum crude oil and 9 DOT 112 tank cars containing liquefied petroleum gas (LPG) in the siding at Gainford, Alberta. Two LPG tank cars were breached during the derailment and caught fire, and a third LPG car released product from its safety valve which ignited. About 600 feet of track was destroyed and a house located directly north of the derailment site was damaged by the fire. A total of 106 homes in the vicinity of the occurrence were evacuated. There were no injuries.
The investigation determined that the train derailed when one or more rail breaks occurred in the high rail as the train travelled through the curve in the Gainford siding. Numerous defects were found along the length of the high rail in the curve. A rail flaw detection test through the area 2 months earlier had not identified these defects. In March 2013, the low rail had been replaced with a new rail that reduced the curve’s superelevation. In this situation, more stress was placed on the high rail, increasing the risk of rail defect development and failure.
One of the DOT 112 tank cars carrying LPG was punctured in the underside by the coupler from another car. This caused it to release its load and explode. DOT 112 tank cars have increased protection on each end to withstand impacts and are equipped with double shelf couplers designed to keep derailed tank cars together during derailments. However, tank cars that come apart during a derailment and jackknife across the track are vulnerable to impacts from following cars. None of the DOT 111 tank cars, which were built to the CPC-1232 standard, released petroleum crude oil, as the cars derailed in a line on their sides and did not suffer secondary impacts.
Following the occurrence, CN conducted walking inspections and rail flaw detection re-testing on all 25 mph sidings. Speed was reduced to 15 mph in these sidings until they were retested. Rail grinding within these sidings was also programmed to remove rail surface defects.