that the initial point of derailment, the wheels first lift off, the linear speed of the train pushes it to the outside. and all the cars follow. the lead car right off the track. it is a pretty horrifying picture. when you look at some of the still shots, what you find surprising about this, is how little track damage there is. which means the derailment was sudden, complete, and straight off the track. >> just flipped it off. >> as if the cars had been tipped over. >> so is there an explanation? to go through speed with me for one more moment. how the driver approaching this. these are really sophisticated trains. my understanding is they're supposed to tell you when you're going too fast and force you to not do that. how could this have happened to go double the speed limit? >> it depends on what the, what we call the train control sterm in use was at the time. there are more advanced train control systems that automatically enforce speed