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As an example to demonstrate the relativity of simultaneous events Einstein used the train thought experiment. The argument envisages a very long tran moving at constant velocity with respect to an infinitely long embankment. A lightning strikes the embankment at a point A coincident with one end of the train, while a second lightning strikes at a point B coincident with the other end of the train. The lightning strike events are deemed to be simultaneous by an observer standing on the embankment at point M which is at the middle of the distance A to B. Another observer is sitting in the middle of the train at point M' coincident with point M when the lightning bolts strike. The argument concludes that the observer in the train will not see the two flashes of light simultaneously, because by the time the flashes reach the observer, the train would have moved a distance closer to one of the flashes and the same distance away from the other flash.
My difficulty is in reconciling this conclusion, when one considers the situation from the point of view of the observer sitting in the train only, or in other words if the embankment is removed. Without the embankment, the train can be considered stationary as there is no way of deciding whether the train is moving or not. In this scenario, using essentially the same argument used for the Earth bound observer above, the two lighting flashes hitting the ends of the train would be seen as being simultaneous by the observer sitting in the train at point M' midway along the train. Obviously these two results are contradictory. What am I missing?
My difficulty is in reconciling this conclusion, when one considers the situation from the point of view of the observer sitting in the train only, or in other words if the embankment is removed. Without the embankment, the train can be considered stationary as there is no way of deciding whether the train is moving or not. In this scenario, using essentially the same argument used for the Earth bound observer above, the two lighting flashes hitting the ends of the train would be seen as being simultaneous by the observer sitting in the train at point M' midway along the train. Obviously these two results are contradictory. What am I missing?