After the Montreal, Maine & Atlantic Railway train pulled into the Nantes station in Quebec, the engineer had some basic duties to perform to secure the cargo of crude oil – but an unlikely combination of events led to the deadly derailment in Lac-Mégantic.
The eastbound train had stayed put on stopovers in the past, though details about the routine on previous trips are unknown. This time, however, there was a fire on one of the locomotives to disrupt the air-brake system and MM&A says the engineer didn't set enough handbrakes on the tank cars. Also, there also wasn't another knowledgeable employee on hand to help lock down the train. Combined, the sequence of events doomed the MM&A train to run away unattended, say industry, union and safety experts.
Shortly after stopping in Nantes at 11 p.m. on July 5, the engineer's list of routine chores should have started with applying the handbrake on the lead locomotive, repeating the process on the other four locomotives and then setting the handbrakes on some of the tank cars.
MM&A chairman Edward Burkhardt said Wednesday that his engineer did not apply an adequate number of handbrakes. The company previously said it believed the engineer had set the handbrakes on five locomotives and 11 tank cars.
Applying the handbrakes is a labour-intensive process, especially for this train, which stretched over a distance of 1.4 kilometres.
The engineer needs to climb onto a step on the tank car and manually turn the handbrake, which resembles a large wheel. It should take two or three minutes for each handbrake, with the engineer going consecutively from one tank car to the next one further up the hill. If done properly, there should be a block of locomotives and tank cars with each of their handbrakes set.
From Nantes to Lac-Mégantic, the tracks are on a grade of 1.2 per cent – meaning that for every 100 metres of distance, the vertical drop is 1.2 metres. That grade is steep enough that under some railway guidelines, to be on the safe side, 30 of the 73 handbrakes on the cars, or 41 per cent, should have been applied, The Transportation Safety Board of Canada is investigating whether the engineer carried out his duties, part of a probe that will take months to determine what caused five locomotives, 72 tank cars filled with crude oil and one buffer car to roll down toward Lac-Mégantic.
At 11:50 p.m. on Friday, July 5, a witness reported a fire on one of the locomotives to the rail traffic controller, according to the TSB. Shortly after midnight on July 6, local firefighters put out the flames and the engine was shut down, with an MM&A employee on site at the time, according to the TSB. The engineer, Tom Harding, had already gone to a hotel.
TSB investigators have been looking into the locomotives' air-brake system, in which lowering the air pressure applies the brakes and raising pressure releases them. An air-brake line is charged at 90 pounds per square inch, and when an engineer reduces the pressure to 65 PSI, it puts on the brakes. One question that needs to be answered is how the air brakes were released. One possible circumstance investigators are looking at is that a relatively small change in air pressure could have produced a "pressure wave" to trigger a quick release.
"To give you a simple answer about the air brakes is not possible," Ron Johnston, the TSB's acting director of rail investigations, said in an interview. "There is a mountain of information, and it's still coming in."
In any case, even without functioning air brakes, having a sufficient number of handbrakes applied would have kept the train in place. The engineer also needs to conduct a test of the handbrakes, by using locomotive power to see whether the train will budge by pushing and pulling the tank cars.
After the firefighters and the MM&A employee left the scene in Nantes, the train started moving on July 6 at 12:56 a.m.
At 1:14 a.m., after travelling nearly 12 kilometres, the train derailed in Lac-Mégantic, triggering a series of deadly explosions.
The types of tank cars that crashed in Quebec have a long history of failing to withstand derailments, reinforcing the view of critics who say it's time to phase them out.
Tank cars themselves are typically either owned by the companies doing the shipping, or those firms have leasing arrangements with the tank-car manufacturers or third parties.
While the rail industry relies on the tank cars as its workhorses, signs of inadequate design date back more than two decades.
It is unclear whether even a newer model of tank cars could have withstood the impact of the MM&A derailment, but safety experts say having improved types of tank cars would at least help reduce the damage in less severe crashes.
MM&A received approval last year from Transport Canada to operate with a one-employee crew. In the 1970s in North America, some freight trains had as many as five employees for each shift. The engineer would focus on operating the locomotive. Others on board were the conductor, an engineer's assistant (called a fireman) and two brakemen – one for the front and the other for the rear. At the end of the train, there used to be a caboose, which served as spartan shelter, but the caboose was phased out in the 1980s. Crew sizes gradually shrank over decades.