LAC-MEGANTIC, Quebec Train Wreck.
 

I'm looking at the explosive fire from crude oil takers (?) Why ? I don't see how thick crude catches fire like that. I can see how crude would burn.... but explode ?

My buddy next door ran OTR hot oil tankers...oil at very high temperatures in a thermos style semi tanker trailer. He had one roll over and split at high speed and there was no fire, just a mess to clear up and an EPA fine to pay.

What kind of crude is flammable enough to burn in this instance. I know North Sea oil light crude is thin but wasn't this stuff from the tar sands ?

Train in Quebec wreck carried crude sold by World Fuel Services | Canada | Reuters

You don't suppose something other than crude was being hauled, do you?



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The other weird aspect of this disaster mentioned on the CBS news tonight is that the train was parked outside of town and caught fire. Firefighters and company officials were called, fire was put out and everything was declared fine. This was in the hours immediately before the explosion.

But I'm with you--how does crude explode?

Plenty of lighter diesel oil available on the locomotives to start things going. "Explosion" may be media hyperbole for "a sudden, large, and intense fire."

Lac-Megantic Train Explosion | Fire Doused On Runaway... | Stuff.co.nz

That explains why the train rolled away.

So the numbskulls didn't set handbrakes before leaving the train? I see jail time in someone's future.

"'If the operating locomotive is shut down, there's nothing left to keep the brakes charged up, and the brake pressure will drop finally to the point where they can't be held in place any longer,' Ed Burkhardt told the Toronto Star.

Canadian crash investigators said they will look at two sets of brakes on the train, the air brakes and the hand brakes, as they probe what could turn into Canada's deadliest rail accident since 1956."

Weird that train brakes aren't like truck brakes which lock up if air pressure drops.

I start my shop wood burner with used motor oil. Takes a squirt of gasoline or cleaning fluid to get it going and it does not 'explode' and certainly does not roar out of control like the scene pictured in the news and tv.

I'm looking at towering inferno type flames here. Even if the loco had a diesel leak it still seems unusual for crude to vaporize like that, especially with the experience of the rolled semi tanker as in my first post.

Those tankers are filled to the top so little room for trapped volatile vapors. and as it was tar sand crude it seems even more like there was a large amount of ignition fuel.

The loco carries 3000 gallons of diesel in under slung side tanks. The semi carried 200 gallons in similar tanks that split open but no fire after a 70mph roll over on black top road surface.



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They are, though the pressure in the line is also needed to pump up tanks on the cars that provide the application force. If line pressure drops < tank pressure, the brakes apply. However, if the line is kept at zero pressure, pressure in the tanks will eventually leak down to zero and the brakes will release.

Interesting thought: what if the firefighters had isolated the line by hitting a valve while fighting the engine fire? Then the pressure in the line wouldn't have been able to drop to apply the brakes.

The engineer is responsible for locking down a train parked up. There are screw down brakes but I doubt he would have bothered being as he left the loco engine idling.

In view of this description, how did it run away?
https://en.wikipedia.org/wiki/Railway_air_brake

When firefighters left they said "......security of the train was down to 'them'." ( the railroad crew.)


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Photos: Lac-Megantic, before and after | Globalnews.ca

Interesting how all the cars ended up alongside each other like sausages in a package. Do derailments usually occur like that? I would have expected more of a mishmash of cars in a variety of directions.

Terror event?

Yes, that explanation suggests it is very difficult for a train to run away.

So now we have trains..unattended..idling...unlocked...and for three days ?


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I was thinking fume build up and boom?

Crude is a mixture of lots of stuff. Including a lot of volatiles.