I think it was a short movie or animation (2-3 min). Its about the story of life (love, betreyal, cancer etc) of two people from their first meeting until their death. On the screen you are only can see wires (like from the train) and you are like inside that train watching on them. And while the picture is moving forward you can hear a story. And the story depends on how near or how far wires are. Until they ended.