Taking the commuter train to and from Dublin, sometimes another train on the other direction passes and it's a bit unnerving. I cannot imagine such a collision between two high speed trains :(
I have the same feeling riding the TGV in France. When another train passes in the opposite direction, the pressure in the interior of the cabin even changes. Not sure if it lowers or raises, but I can definitely feel it in my ears.
Look for train collision in Greece (1), the only in a developed country. Extensive research has been done, from a simple switch malfunction to plasma scale temperatures.
