A problem I struggle to conceptualise as I have began leanring about relativity and seek your guidance and knowledge on: Consider a stationary observer at point A. Relative to the observer there is a train travelling at -0.6c. A passenger on board the train has a particle gun, and fires it in the same direction of the trains travel. The particle is fired at a speed of 0.6c relative to the train. Ignoring all logical rules as to why this couldnt happen, why does the particle fired not have a velocity relative to the observer of 1.2c?