I am not seeing anything as to cause... was the power still coupled to the unit train? If not, the cut of cars would have had to have had the air bottled up before the cut... not likely.
I do recall seeing a video of the inferno... and in the foreground was the end on the unit train with End of Train device blinking away.
So... where was the power. I could dig around on the railfan boards, but would rather not. I have enough crude oil unit train derailments to contend with at the moment.
It's got to be either the Nantes FD or some saboteur.
Though I still can't comprehend how the tank cars got to town before the locomotives (which apparently never arrived) since that was the direction of travel of the train.
Though I supposed the locomotive that was supplying air ran out of fuel or stalled from some other reason. Locomotive control positions will be interesting.
The only thing I can imagine is that someone cut off the locos from the head of the train and parked them on a parallel track (There is a long siding just out of Nantes according to aerial photos) and then the tank car consist took off. Then the locos could have been moved part way to Lac Megantic behind the explosive materials.
Well, there was one mention of the locomotives being a few miles out of town. I had assumed that they were west of town, but it likely seems they are east of town and led the whole train through town where wile going at a higher speed than normal the tank cars started to derail while going over the switches located in town.
But someone managed to shut down the fifth locomotive unit, he said. Thats the one that maintained brake pressure to keep the train in place.
If the operating locomotive is shut down, theres nothing left to keep the brakes charged up, and the brake pressure will drop finally to the point where they cant be held in place any longer, Burkhardt said.
There are two ways to shut down the fifth unit: Theres an emergency lever on the outside of the locomotive that anyone wandering by could access. Or, there are a number of levers and buttons inside the unlocked cabin.
Both means were used, said Burkhardt."
Sounds like someone should have set the manual brakes on some of the tanker cars. Or leave the train in some low spot where it's uphill in both directions.
It'd be better to just keep the train going 24/7.