Of course it happened when I had a visitor. The train had set off from Golden Lake, and was triumphantly passing the Pembroke freight shed, having stayed obediently on the track for the whole run. But when it stopped short, no amount of cajoling would move it. I finally looked at the command station, and it indicated a short, sadly ending the demonstration.
Oh how I searched for the source of that brief buzzing sound that presages the circuit breaking! Because the train was in motion, when it happened, I suspected something had fallen on the track. Nada. The sound seemed to originate near the station area, and I could spot nothing. I began disassembling electrical circuits – easy ones on terminal strips first – and confirmed the suspicion. I was about to start cutting rail, but went to bed instead.
Overnight, I had the idea to listen for the buzzing beneath the layout. The next day, I did that and sure enough, the buzzing was louder. I inspected the bus connections and feeders, looking for shiny bits that now contact one another.
It was as I was craning my neck to inspect the switch controls behind the paper towel holder that my gaze swept over the test track. And there it was – the coupler height gauge! I hardly ever use the thing, but must have had it out to check the coupler height on the CPR ore car.
It was the easiest short to fix, but the hardest to find.
Pembroke:87 