White River Ontario - The Transportation Safety Board of Canada (TSB) has determined the derailment of a CP freight train in northwestern Ontario, which led to an oil spill, was due to a rail fracture caused by a broken wheel.
 
In TSB investigation report R13T0060 released today, the board says the train was travelling from Edmonton to Toronto on 3 Apr 2013, when an "undesired emergency brake application" happened near White River, Ontario.
 
It says this happens 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 DOT-111 tank cars, and the report says seven of those contained petroleum crude oil, which is classified as dangerous goods.
 
Several cars rolled down an embankment but there were no injuries.
 
The report says three of the derailed tank cars spilled their contents, a total of almost 102,000 litres of crude oil from two of them, and 18,000 litres of canola oil, which is not considered dangerous, from the third.
 
The investigation determined there were no issues with the handling of the train and no track defects in the area of the derailment.
 
But it says four days before the derailment, a trackside wheel impact detection system had recorded an impact that was above the Association of American Railroads' threshold for wheel removal, but company guidelines permitted the wheel to remain in service.
 
The wheel later failed and fractured the rail, causing the derailment, the report says, adding that the top and bottom fittings on the dangerous goods tank cars did not adequately protect against a spill.
 
The TSB says after the incident, Transport Canada and the railroad association began talks on design improvements to Class DOT-111 tank car bottom outlet valves to prevent spills during a derailment.
 
The Association of American Railroads has since proposed design improvements to tank car bottom outlet valves.
 
The TSB investigates transport incidents for the purpose of improving safety but does not assign fault or determine liability.

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