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My last years working as a railroad machinist were spent working on locomotive air brakes. In most situations, the system is fail safe. I always chuckle when I see a movie where a train separates, as it did in the latest James Bond thriller, and both ends of the train keep going. This is close to impossible in real life, the air brake system automatically will go into emergency braking if there is a break in two. When a locomotive engineer applies the brakes to a train, he or she makes a “reduction”
of the equalizing or control air, which then triggers a brake application. This reduction of equalizing air, in the case of a break is the key to emergency brake applications. There is much more to the system, of course as it was refined over time, but its all based on this concept.
What we know so far in Quebec, is that the oil train was parked on a grade. The brakes were set by the crew, at some point the brakes came off, and the train rolled into the little town of Lac-Megantic, derailed and exploded, leaving many dead and the town devastated.
Why would the brakes come off? After all, I seriously question that this was the first train parked on this grade, it must have been a routine practice for a crew, they must have felt that this was not a big risk. And most of the time it probably wasn’t.
But where you have compressed air running through valves and pipes you have the possibility of leaks. On my job, the locomotive generally was considered OK for service if it had a leak of less than three pounds per minute. As I remember, the passing score for an entire train, which is tested before departure, is eight pounds per minute. Hopefully of course it will be much less than that. When I was working, I always tried to achieve no leaks on the locomotive itself before it left the shop.
An entire train, however, is another matter. You have train line hoses linked between every car, and piping from the small reservoir on each car, all potential leak sites. Given this I have to wonder why it was routine to park a heavy oil train on a grade. You just have to do some simple math to figure out how long it would take for a leaking pipe to drain the air from the system. Air is stored in the locomotive reservoirs at 130 psi, the train line is 90 psi. And remember, you are allowed 3lbs per minute for the locomotive and a bit more for the train.
So this train, part of the massively growing “pipeline on rails”, which takes advantage of the lack of sufficient pipeline capacity, was pulling more than 70 cars, loaded with crude oil. If it was only crude oil, you would have to wonder why the explosion? Crude is more like tar than the gasoline we put in our cars. In order to ship crude by rail or pipeline however, it has to be diluted for it to flow easily. Dilbit, which I guess must be short hand for “diluted bitumen”, is the standard substance used. According to Wikipedia, dilbit is made up of bitumen diluted with “natural gas condensate.” And guess what, this condensate is sometimes called “natural gasoline.” Gasoline? No wonder the town of Lac-Megantic blew up.
So there you have it, whether its being transported by the “pipeline on rails” or the Keystone pipeline, you have not only the possibility of spills, but also massive explosions as in Quebec.
The debate needs to move from mode of transport to whether this tar sands muck can be safely transported at all.
Jonathan Flanders spent 25 years as a Railroad Machinist, member and past President of IAM 1145. Steering committee member of Railroad Workers United. Retired. He can be reached at: email@example.com.