Misaligned rail joint led to derailment of CN crude oil train in 2019

Written by David C. Lester, Managing Editor
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Aerial view of derailment site

The Transportation Safety Board of Canada released an investigation report on the 2019 derailment of a loaded CN crude oil, saying that the derailment was caused by a misaligned rail joint bar that eventually caused the rail joint to fail.

A summary of the investigation is reproduced below.

In its investigation report (R19W0050) released today, the Transportation Safety Board of Canada (TSB) determined that a recently replaced rail joint failed as a result of a misaligned joint bar, causing the derailment. The misalignment led to a loosening of the joint and initiated fatigue cracking in the joint bars which failed beneath the train as it traversed the area.

On the morning of 16 February 2019, at about 02:17 Central Standard Time, a Canadian National Railway Company (CN) unit train, consisting of 108 tank cars loaded with petroleum crude oil and two covered hopper cars loaded with sand, was proceeding eastward on the Rivers Subdivision at 49 mph (79 km/h). The train was designated as a key train operating on a key route. As the train proceeded, it experienced a train-initiated emergency brake application near St-Lazare, Manitoba. Subsequent inspection determined that 37 cars, all TC /DOT Class 117R tank cars, had derailed near Mile 197.47. A total of 17 of the derailed tank cars were breached, which resulted in the release of about 815 000 litres of product. About 1000 feet of track was damaged or destroyed. There was no fire, there were no injuries, and no evacuation was required.

The failed joint had been repaired about six weeks prior to the accident. During the repair, a compromise joint bar, an offset joint bar used for joining two rails of different sizes which looks similar to a standard joint bar, was inadvertently installed with a standard joint bar. A joint assembled in this manner is unstable, will loosen over time, and can result in premature failure such as in this occurrence.

 

The 7th to the 41st tank car (35 cars) all sustained some form of impact damage during the derailment. Damage to tank shells, tank heads, bottom outlet valves (BOV), manways and protective housings resulted in 17 of the 35 cars being breached. (Footnote: Any tank car damage that resulted in a release of product was considered a breach of containment.) TSB

The failed joint was one of five in the south rail located within a relatively short distance of 49 feet. The five joints and associated plug rails adversely affected the vertical stiffness of the track in that area and led to a more rapid deterioration of the failed joint. The investigation also found that despite having a joint elimination program for the CN Rivers Subdivision, about 1500 joints and the associated plug rails remained in continuous welded rail territory. The volume of joints and plug rails indicated that the track infrastructure was deteriorating.

As part of this investigation, the TSB conducted a comprehensive examination and analysis of the derailed Class 117R tank cars. In general, the new tank car performance was somewhat improved when compared to the legacy Class 111 tank cars. While improved tank car structure design has been shown to reduce the probability of dangerous goods release and the potential severity of an accident, the risk of a tank car being punctured or breached and releasing product remains in any derailment if the speed is sufficiently high.

Following this accident and two additional serious Canadian Pacific Railway Limited crude oil unit train derailments near Guernsey, Saskatchewan (R19W0320 and R20W0025), the TSB issued Rail Safety Advisories (RSA) 02/20 and 03/20 to Transport Canada (TC). In response, TC issued Ministerial Orders instructing the industry to develop revised Rules Respecting Key Trains and Key Routes and Rules Respecting Track Safety. The rules were subsequently revised and now contain a number of safety improvements related to the operation of key trains and track infrastructure.

Since this accident, CN now requires the outside surface of all compromise joint bars that are exposed when installed in track, to be spray-painted royal blue by the supplier. This allows for compromise joint bars to be more easily differentiated from standard joint bars.

Between 1 March and 31 December 2019, on the Rivers Subdivision, CN eliminated a total of 1019 temporary plug rails (2038 rail joints) and installed 192 867 feet of continuous welded rail.

See the investigation page for more information.

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