Whatever it was, it apparently spilled out of the truck, and there was enough volume to make a pretty big burst of flames on the other side of the train. And I doubt it was alcohol, given the orange/red flames. I was leaning more toward some sort of flammable solvent(s), but I didn't see any placards. I hadn't thought about dust, though, or the magnesium components of the trailer starting the fire. Good points, Frank.