OHS Canada Magazine

News

Wheel defect led to 2014 derailment and fire: TSB report

Damage was missed in wheel's ultrasonic testing in 1991, safety board says


A broken wheel in the 13th car of a Canadian National (CN) freight train caused track damage that spiraled into the derailment of 19 cars and a locomotive near Plaster Rock, N.B. on Jan. 7, 2014, according to a new report from the Transportation Safety Board of Canada (TSB).

Nobody was injured or killed in the accident, but the train’s tank cars spilled about 230,000 litres of crude oil, sparking a fire that led to the evacuation of around 150 nearby residents. The incident also destroyed more than 105 metres of track.

The CN train was travelling from Toronto to Moncton when the derailment occurred, just after 6:45 p.m. that day. According to the TSB’s investigation, the L3 wheel on the 13th car broke as a result of wheel fatigue due to a very large area of porosity under the surface; this damage had not been detected during the wheel’s initial ultrasonic testing in 1991, nor was it found during the wheel’s 2006 re-profiling.

“The impacts generated when a part of the tread detached from the L3 wheel caused the wheel plate to break, which caused the wheel to come loose and slide inside the gauge and then derail,” read the report, which was released on June 19 of this year. “After the L3 wheel left the running surface of the rail, the R3 mating wheel derailed inside the gauge and began striking the spike heads and anchors over several miles, causing rail failures.”

The report also revealed that the train had been carrying crude in Class 111 and 112 tank cars.

“This accident and other recent accidents in North America, including the one at Lac-Mégantic, have illustrated the vulnerability of Class 111 tank cars to damage in a derailment and to product release,” the report read, referring to the fatal derailment and explosion in Lac-Mégantic, Que. in July 2013. “If Class 111 tank cars that do not meet enhanced protection standards transport flammable liquids, there is an ongoing risk of product loss and significant damage to persons, property, and the environment when these cars are involved in accidents.”

On May 1, Transport Canada announced a new standard for tank cars, the 117, designed to resist puncture and heat. The government has also been phasing out all of the Class 111 tank cars being used for carrying dangerous goods in Canada.

The TSB report noted that ultrasonic testing of wheels had become stricter since the broken wheel’s original manufacture. “Most failures due to shattered rims occur when the wheels are fairly new,” stated the report. “There is reason to believe that the action taken by the industry has improved detection of defective wheels before they are placed into service and, as a result, reduced the risks of failure due to shattered rims.”

Since the Plaster Rock incident, CN has seen other derailments, including three in Northern Ontario within less than a month in February and March of this year.