Originally Posted by Dale Manquen:
You might check:
CFL fluorescent fixtures
Wall warts (I have an Ipod charger that wipes out my AM radios bigtime!)
Dimmers
Power control devices such as X10, especially controlling power to the trains
Tube fluorescent fixtures
Any electronic device that might have line bypass capacitors that are arcing, even when the power isn't on. Unplug everything electronic.
WOW I have all this stuff down there. The Fluorescent lights are only on when I'm working on the layout. I have track lighting for operating, on a dimmer. Lots of duct work above layout and steel I-beam along the whole length, 30ft, of layout.