Derailment of Canadian National freight train at Plaster Rock, New Brunswick, 7 January 2014

DORVAL, QC, June 12, 2014 /CNW/ -

The occurrence

On 7 January 2014, a Canadian National freight train was travelling from Toronto, Ontario to Moncton, New Brunswick, with 122 cars, 3 head-end locomotives and 1 remote locomotive. On the main track near Plaster Rock, New Brunswick, 19 cars and the remote locomotive derailed.  Nine of these cars were carrying crude oil and liquefied petroleum gas. There were no crew injuries. Approximately 150 people near the accident site were evacuated due to the resulting fire.

While passing by a Wayside Inspection System (WIS), the crew received an alarm. Following normal procedures, the train was slowed down while minimizing in-train forces. However, before the train stopped, the rail cars began to derail resulting in a brake pipe separation and the application of the emergency brakes. Once the train came to a full stop, the conductor walked back towards the derailment site and found a broken wheel on the 2^nd axle of the 13^th car. This axle had derailed, with both wheels positioned inside the track gauge.

Work Completed to Date

TSB investigators and specialists from the TSB Engineering Lab have completed the field phase of the investigation. This includes the collection of the locomotive event recorder data, the results of previous wayside inspections, initial train inspection, and inspection of the track.  The tank cars were photographed and documented for further analysis.

The broken wheel found at the occurrence site was documented and shipped to the TSB Engineering Lab for testing. Information was collected from the railway company, and officials and witnesses have been interviewed.

What We Know

The broken wheel failed due to fatigue. A crack initiated at a porosity and travelled under the running surface of the wheel which caused a shattered rim. The subject wheel was manufactured in 1991 and met the material requirements for that time period.  Wheels manufactured today undergo an ultrasonic inspection of the tread area to check for areas of porosity. This inspection procedure is carried out to detect and prevent wheels with significant areas of porosity, such as found in the subject wheel, from being placed into service.

Track damage occurred as a result of the derailed wheels battering the base of the rail. Subsequently, multiple rail fractures were found between the initial point of derailment and the derailment site.

Two of the tank cars were the primary source of the released oil that created the fire.  Both were older Class 111 tank cars, built in 1984 and 1996. The punctures in the head portion of the tank cars were most likely due to impacts with the adjacent tank car coupler assembly.

Three CPC-1232 (design specification for Class 111 cars introduced in 2011) tank cars also derailed and were examined by the TSB team. One car was essentially undamaged, while another car had some damage associated with sliding on its side after derailing. Neither of these tank cars released product. The third CPC-1232 car did not initially release product. However, this car came to rest in the pool fire, resulting in the eventual degradation of the bottom outlet valve gasket and a small release of product.

Next steps

Work continues as this ongoing investigation is in the examination and analysis phase. Investigators will interview the train crew to confirm further details.  The team will review the history of the wheel as well as its manufacturing process and look closely at the effectiveness and adequacy of Wayside Inspection Systems and other inspection methods to detect problems with wheels and axles in service. Lab work continues on the detailed examination of the damage to tank cars in order to draw conclusions about their performance. Once this phase is complete, the report writing phase will commence.

Communication of Safety Deficiencies

Should the investigation team uncover safety deficiencies that present an immediate risk, the Board will communicate them without delay so they may be addressed quickly and the rail system made safer.

The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability. 

SOURCE: Transportation Safety Board of Canada