I think “don’t turn the controls on railroad cars” is the key point here. That said, unless I’m missing something about US railroading generally, surely there’s a duty of care on the owners of the car? Is THAT why charges aren’t being brought?
The point about the change in elevation is an interesting one. Railroads tend to favour smooth transitions and constant gradients. It’s a curious thing about human vision, that it can’t judge gradients except by contrast. There is a well-known error of perception by which a constant, shallow gradient is taken to represent a horizontal reference.
