I don't know either. I was on a railroad track once when train (going only about 4 mph) hit the semi truck trailer next to me and it was pushing the truck toward my car. I was frozen. Fortunately, the train was going so slowly, it only pushed the truck about a couple of feet and there were still two feet between the truck trailer and my car when it stopped, but I couldn't get myself to back off the tracks until everything stopped......not a good sign.
These videos are amazing.