Broken Rail As Possible Cause To Canadian Crude Train Derailments

A March letter from Transportation Safety Board (TSB) investigators to Transport Canada suggests that broken track might have contributed to recent derailments of trains carrying crude oil, including two accidents involving Canadian Pacific Railway Limited CP trains in February 2020 and December 2019.

As a result, TSB investigators are recommending that Transport Canada update its regulations regarding track standards for key routes, especially since the last updates were made in May 2012 and the industry has evolved to running longer and heavier trains since then.

"As train operations have evolved, the TSR [track safety rules] have not kept pace…While the TSR establish minimum standards for track infrastructure, there are no provisions in the TSR to address the need for enhanced track standards for key routes despite sometimes significant increases in DG [dangerous goods] traffic volumes," said the March 4 letter by Dan Holbrook, acting director of rail/pipeline investigators for TSB, to the Director General for rail safety for Transport Canada. 

The letter explained that changes in the rail industry have enabled CP and Canadian National Railway Company CNI to run longer and heavier trains.  

"Over the past 10 years or so, train operations have evolved and there have been a number of operational improvements implemented throughout the rail industry, such as the proliferation of distributed power technology. These advancements have facilitated more effective management of in-train forces allowing for longer, heavier trains," TSB said. "Similarly, train traffic has evolved and generally increased as more DG are transported in either large blocks of cars within a merchandise train or as unit trains that transport a single DG product such as petroleum crude oil."

But as the rail network was handling longer and heavier trains, public and private stakeholders hadn't fully considered the wear and tear that those trains would have on train tracks. For example, broken joint bars or a broken rail were determined as factors contributing to two crude train derailments involving Canadian National (CN) in 2015. CN's investigators initially didn't take into account how increases in train traffic and tonnage could degrade track more quickly, according to TSB. 

Following the incidents, CN made significant capital investments to track infrastructure in the Ruel Subdivision, and it improved its track inspection and maintenance practices. Although the track is still classified as Class 3 track, there hasn't been a significant main track train derailment on that subdivision since March 2015, TSB said.

TSB investigators pointed out that seven accidents in recent years involving trains carrying dangerous goods were "related to failures of track infrastructure."

Furthermore, while the freight rail industry has used the tactic of reducing train speeds to prevent train derailments, that action, plus the deployment of the newest tank cars, aren't enough to prevent punctured tank cars in derailments, TSB said. 

The February 6 incident of a derailed CP train near Guernsey, Saskatchewan, involved DOT 117J100-W specification tank cars, which were industry standard and are the newest tank cars available to transport Class 3 flammable liquids, according to TSB. 

"The derailment occurred at a speed that was permitted by the Rules Respecting Key Trains and Key Routes in force at the time and the crude oil was transported in DOT 117J100-W tank cars, which have significant design improvements when compared to legacy DOT 111A tank cars," TSB said of the Feb. 6 incident. "Despite using the best tank cars available, about 27 of the tank cars released an estimated 1.6 million litres of product. This suggests that the recent tank car design improvements alone are insufficient to fully mitigate the risk of adverse consequences resulting from derailments involving DG."

Although investigations for the December 2019 and February 2020 derailments are still ongoing, "the suspected cause appears to be related to a broken rail," TSB said. The agency also said the Sutherland Subdivision was maintained at a Class 4 standard when the two derailments occurred.

Following receipt of the letter, Transport Canada modified in April the speed restrictions for key trains carrying dangerous goods. 

Transport Canada didn't return a request for comment by press time about this issue.

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