The Veterans parade train wreck - this is sad and astounding at the same time

[Drunken Irishman]

5. Well...

My question comes from the fact that the gate would've been down well before the train hit. If it was, how did the truck manage to get past it to the point where the trailer was actually hit by the train? The video makes it seem as if the gate came down at the time the train rolled over the road - which doesn't sound possible.

So, what exactly happened? What part of the trailer was hit? The animation is just bad and doesn't answer any questions.