The Signalman Poltergeist: The Legacy : Season 1 Episode 20

A psychic/supernatural occurence debunker and physicist, Dr. David Praeger, is working for the army at an old railway station & tunnel in Powderwash, Colorado. The army is planning on opening a nerve weapon disposal site nearby and he is there to find out what causes the magnetic fluctations in the area. While investigating he starts seeing the 'ghost' of a signalman telling him to 'pull the switch'. Alex finds out where he is after dreaming that he is in danger and, as much as they dislike the man's work the Legacy go to try and save him.