Well, you have to understand that when a train derails—and you say there's some history to it—the train is like a snake, so it could be on a curve. The only way we know what's happened when the train has come to an emergency stop is to actually go back and take a look at what's happened. You can only do that from the lead of the train. There's nobody on the tail end any more.
So you would walk back, and it could be just around the corner, and it might just be a pull apart. It might not be a derailment at all, or it could be a major derailment. So you don't know until you get back there what you're facing.