No problem. The point is that if the train passed the front of the platform it passed the front of the platform. It doesn't go backwards when Ooke slams on the brakes to end up not passing the front of the platform.JesseM said:If the train passes the front of the platform in one frame, it must pass it in all frames. Different reference frames cannot disagree about local events which occur at a particular time and spatial location, like one object passing arbitrarily close to another.
Edit: sorry, I get what you mean now. I was thinking whole trains and whole platforms. Apologies. Perhaps we should resurrect the collision to guarantee local events. A platform ending with buffers perhaps?