I don't think so. In a head-on accident where the stop is truly sudden and uncontrolled, rarely do the cars stay upright, on the rails.A moving train is always traveling forward, and that forward momentum will decrease (stop), regardless of the cause of the accident. And the most violent accidents are head-on.
In the vast majority of "train accidents" whether the driver of the vehicle got out in time is likely to be of far more importance than whether people are in forward or backward facing seats.