CALGARY, Alta. – In its investigation report (R13C0087) released today, the Transportation Safety Board of Canada (TSB) determined that a Canadian Pacific train derailed when a wheel flange struck and climbed a switch point and then fell between the switch point and the rail.
On 11 September 2013, the freight train departed from Alyth Yard in Calgary enroute to Red Deer, Alberta. As the train crossed over the switch, it derailed seven tank cars loaded with natural gasoline condensate (a product commonly used to dilute bitumen so that it can flow through a pipeline). During the derailment, approximately 600 feet of track was destroyed and a natural gas line supplying a switch heater was severed, prompting an evacuation in the vicinity. There were no injuries or product loss from the tank cars.
The investigation determined that wheel flanges striking the switch point had caused overstress impacts on the tip of the switch point, creating a ramp for the wheels to climb up and derail the seven cars. Given the track layout, including a combination of curves, the transition from empty to loaded cars entering the crossover likely resulted in the wheels of the loaded cars tracking more towards the standard switch point.
Following the occurrence, Canadian Pacific made improvements to the track infrastructure, including removing the switch points involved in this occurrence, upgrading the rails and installing a new turnout.
The transportation of flammable liquids by rail is a Watchlist issue. The TSB is calling for railway companies to conduct route planning and analysis, and perform risk assessments to ensure that risk-control measures are effective. Additionally, flammable liquids must be shipped in more robust tank cars to reduce the likelihood of a dangerous goods release during accidents.