If a train goes past an observer at 100km/hour and someone on the train fires a bullet from a gun in the direction the train is going at 700km/hour, then relative to an observer, that bullet will go past at 800km/hour. Einstein made a statement of the type that if a person on the train holds a torch they will see the light beam at the "speed of light" and an observer on the ground will also see that light beam at "the speed of light" ie the speed of light is always constant from any frame of reference. He then proceeded to make a theory which included time speeding up or slowing down to explain why the speed of light is always constant for any frame of reference. But that was because he thought that the light beam should behave like the bullet in that you could add the speed of the train to its speed and because you couldn't add the speed of the train to the speed of light, he made a fairly complex theory to compensate for it not behaving like the bullet. Yet the light beam has many differences to the bullet. It is instantaneously produced from the torch or flashlight. The bullet is carried onto the train. The light beam is instantaneously produced. Is the light beam actually "on" the train. Do the photons of the light beam at any time rest on any surface of any thing which is on the train or do they simply emanate from the torch? If the photons are not "on" the train, they will not carry the velocity of the train. Therefore you would expect the speed of light to be the same for any frame of reference without having to do any compensating for it. If this logic is not correct, please let me know where you think I have gone wrong.