Passengers report that the train driver braked hard just before the crash but could not prevent the impact.
All eight carriages and the two engines remained upright for a short distance until they reached a set of points down the line from the crossing. Some then toppled onto their sides while others ended up leaning at an angle.
Seven people died in the impact including the train driver and the occupant of the car. Eleven others were seriously hurt and many more suffered minor injuries.
Ambulances from five counties helped ferry the injured to hospitals at Reading and Basingstoke.