I am not a ghost believer. However, I do listen to Coast to Coast AM with George Nooray and Art Belle.sign1
Here's a good question, you mention EMF? I am a Ham Radio Operator. If my antennas are not properly tuned. I can have high RF field's in the station. Guest what? My model trains are next to my radio station. As a Ham, my max power is 1500 watts Effective Radiated Power (ERP).
To make an antenna resonate or tuned. It needs to be cut a certain length. Here's the formula: f(in MHz)/468 This is a half wave antenna. You would cut the wire to it's respective length. Well, if your rails are at a piticular length. It just might be resonate to a certain frequency. Do you live by a Ham Operator, Radio or TV broadcast towe, a high power CB station, or cell tower? This intense RF field can be picked up by the resonate rails. Then turned into electricy for your locomotive.
Do you know if you take a 100w bulb and connect it to my HF (shortwave) transciever. I can make that bulb light up!!!! If I go outside under my Ham Antennas with a florencent bulb while transmitting. The bulb will glow with NO wire attacted!
Long time ago I mention adding 2 .02 microfarad capasitors across the power connections just for that case. This keeps the RF out of the layout. Also keep wires short as possibile. NEVER coil wires. This can act like an expended antenna.
To me it sounds like you have RF in your friends layout. Not ghost! BUT my mind is always open to the possibilities!
Andy
One more possibility is power induction. If you live near high voltage power line. Power can be induced into your rails! NO Joke. That capasitor will remove it!