The Transportation Safety Board says the trend towards longer, heavier trains brings current train marshalling practices into question.
GATINEAU, Que.: The Transportation Safety Board of Canada (TSB) says poor marshalling habits and the operation of longer, heavier trains poses some specific risks to Canada’s supply chain.
In what it calls a trend, the TSB links such marshalling practices and trains to more than ten derailments, including the 2009 derailment of a CN freight train near Brighton, Ont.
Marshalling describes the order in which cars are put together to make a train. The longer the train, the more important the order of heavy and light cars becomes in managing in-train forces. The risk of derailment increases when light empty cars are placed in front of or between heavier ones.
“The way in which this train was marshalled created high in-train forces much like an accordion. Pulling forces separate cars and pushing forces compress them together,” said Rob Johnston, acting director of rail investigations at the TSB. “This caused a “knuckle” connecting two cars to break and the train pulled apart. The heavier tail end then collided with the lighter cars ahead causing the derailment,” he added.
Before 1990, the average train running on Canada’s mainlines was about 5,000 feet long and weighed 6,000 to 7,000 tons. Today, 12,000-foot trains weighing as much as 18,000 tons are commonplace.
“As trains get longer and heavier, the risk of derailment increases. That is why, last March we flagged this problem on our Watchlist, and have pushed hard to make weight distribution on trains a priority,” said Mr. Johnston.
“While the TSB’s warnings have lead to some progress, more needs to be done to ensure longer, heavier trains will always be operated safely,” he added. “The bottom line is, CN needs to manage these risks system-wide and Transport Canada needs to make sure there is an effective, long-term strategy in place for Canada’s railways.”
The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences and accidents.