Canadian investigators issued their first recommendations on Friday after a devastating train wreck in Quebec, urging that trains hauling dangerous goods not be left unattended, and pushing for stricter guidelines on railway braking systems.
Transportation Safety Board (TSB) investigators probing the July 6 disaster in the lakeside town of Lac-Megantic said the "braking force" applied to the train, which was hauling 72 tanker cars of crude oil, was insufficient to hold it in place.
The train was operated by Montreal, Maine and Atlantic Railway (MMA), which is controlled by Rail World Inc, a privately held rail management and investment firm based outside Chicago.
The train had been parked for the night on a main line uphill from the town. Unmanned, it rolled down the track, and derailed and exploded in the center of Lac-Megantic.
An estimated 50 people were killed in North America's worst train accident in more than 20 years, and the town center was destroyed.
TSB investigator Ed Belkaloul did not say how many hand brakes had been set when the train was parked. But he noted there was "enormous variability" in the strength of the brakes, which are located on individual rail cars and operated by manually turning a large wheel that sets the brake shoes beneath the train.
"If you look on your car, if your brake shoes are finished, even if you set them, it won't give you anything," he said. "Same here. The number of brakes is important, but the quality of the braking is also important."
General braking instructions for railways, dating from 1997, state that operators must use "sufficient brakes," and test them by attempting to pull the train back and forth - typically using the engine - to ensure the brakes will hold in place.
"What's missing now ... are specific instructions for a particular place," Belkaloul added. Variables include the number of cars, the grade on which the train is parked and other factors such as local conditions and wind.
Transport Minister Lisa Raitt has asked Transport Canada, the government department that regulates railways, to review the TSB recommendations "on an expedited basis," a spokeswoman said.
Since the accident, Canadian Pacific Railway Ltd, whose guidelines MMA said it was following, has made some two dozen changes to the hand brake section of its General Operating Instructions, according to documents obtained by Reuters.
CP removed a chart that gave minimum hand brake requirements for trains based on the number of cars. That chart had said a minimum of nine hand brakes were needed on a train with 72 cars.
The new rules say hand brakes must now be applied on at least 25 percent of the cars for trains parked on a slope of 1.2 percent, the grade of the tracks outside of Lac-Megantic, unless the brakes have been properly tested.
Canadian National Railway Co, the country's biggest railroad, is also reviewing its policy for securing trains and expects to implement new standards shortly.
The TSB is also analyzing the contents of the tanker cars that did not explode in the crash, looking for clues as to why the crude oil in the other cars exploded so violently.
The train was carrying oil from the Bakken oil fields in North Dakota to a refinery on Canada's East Coast, part of a huge growth in shipments of crude by rail as North American oil production rises and pipelines fill to capacity.
Nearly two weeks after the disaster, investigators continue to sift through what police describe as a crime scene, searching for more bodies and for clues on the cause of the accident.