Please help with this. This is similar to the Einstein train experiment. When C and C' are at the same place, lightning strikes at their location. Both survive though. Assume another prime B' behind C' When B' is at the same location as C, the lightning is at (A,0,0) and (-A,0,0) in the C frame. These are simultaneous events. But, they are not simultaneous to B'. So, C says the lightning is at A and -A when B' and C are together but B' says the lightning cannot be at both A' and -A' (these are located at A and -A respectively when B' and C are together). So, here is my problem. How can B' and C disagree, when they are at the same place, on the distance the lightning traveled along the positive x-axis and negative x-axis? Thanks in advance.