This happened 30 years ago. My sister and I were travelling back from France on the boat train during our summer holidays. We shared a carriage, on the train, with a young couple. We chatted. When I returned to college, in the September, the woman was not only at the same college as me but was in the same halls as I had been previously and in my old room! I did talk to her about it but she didn't remember my sister or I. When we talked about meeting on the train, this is when I realised she was in my old room.We had not talked about college or Sheffield where we were at college.