In this link, the website talks about synchronizing clocks on a moving train. But I have a few questions about it: 1) Why are you allowed to add ct+vt on the left-hand side of the first equation below the picture of the train? I thought one of the main tenants of Special Relativity was that you can't add velocities (or I'd assume distances) without taking into account the dilation/ contraction of that quantity. 2) What would happen if you stopped the train, and then looked at what the clocks say? Would they be synchronized or not? I understand that the train would enter a noninertial reference frame, which would change how they behave, BUT wouldn't both clocks be affected equally... so who is right once the train is stopped- the person who says they're synchronized, or the person who says they're not? THANK YOU SO MUCH!