"Unsolved Mysteries" Show about Dead/Living Twin brothers?

Hello -- about 10 years ago I saw a t.v. show (think it was that Unsolved Mysteries show but not positive) and one episode was a true story about a young boy who one day thought he saw a boy that looked just like him. This mystery boy kept appearing throughout the day, odd things kept happening, and then the "mystery" boy distracted the living boy from getting onto a train that subsequently wrecked. The boy's mother then told him he'd had a twin brother who died either in childbirth or very young so the living twin had no memory. Does anyone remember this show, it's name, etc? It was really really cool. So the dead twin saved his living twins' life. VERY NEAT SHOW/ anyone know of it? Thanks!