The weird thing about this crash is not that the train derailed; its where it derailed. The force overload happened too quickly. The locomotive should have entered the curve too fast, leaned a bit too far, and then overcome its wheel flange, leaving the track at an angle and leaning somewhat out of the curve, pulling cars with it. The effect would be even more pronounced if the brakes were applied at some point, but it should have happened with out braking force, too.
That is not what happened. What appears to have happened is the locomotive left the track almost immediately tangential to the curve, as if its wheels never evenbriefly followed the curve. 80 is nowhere near fast enough for that. The locomotive appears to have gone straight, dead arrow straight, right off of the track. It didnt appear to barrel roll. A few cars tried to follow it, but at some point the rest of the cars seem to follow the curve.
The physics before me do not make sense without some kind of external actor or equipment malfunction causing bizarre attitude prior to or upon the train entering that curve.