I've picked up relativity, again after getting frustrated. I'm new but I need help understanding simultaneity. I tried to read further but it seems to be very important to all of Einstein’s other arguments. So here it goes. In relativity, the special and general theory, P 30 about halfway through to the end of the page, Einstein talks about light how 2 beams of light will reach the midpoint from where they started given that they travel at the same speed. This I understand. Then he talks about how if you are on a train moving toward one of the beams of light from the midpoint that you reach one of the beams of light before the other, and there for it will not appear simultaneous. This to I understand and agree with. But then he says that this means that the two events occur at different times if you are on the train rather than the embankment. I don't understand this leap of understanding from it appears to be to it is. I keep thinking that this is true because you change the distance between two points and therefore are no longer at the midpoint. I would really appreciate someone explaining this.