While running trains this morning, the Blue Comet abruptly stopped at a switch on the main line leading into a passenger station branch. The mechanism of the switch would not move, the breaker on the Z4000 opened, and there was no continuity through the third rail elements of the switch. This switch is an 042 RH Real Trax piece that gets a lot of use on my layout, so it is imperative that it be in good working order.
After digging the switch out of the ground cover scenery and taking it apart, I discovered that one of the copper foil paths in a circuit board had melted itself into the sliding parts of the switch mechanism. The sketches below tell the rest of the story. Although I have a simple fix of the switch, I do not have a solution for the cause of the problem which is momentary short circuiting (sparking) of train wheels as they pass through the switch. Sparking is prevalent as trains pass through everyone of the 16 Real Trax switches on my layout.
