Monk Subdivision - Sherlock Holmes and The Short

Yesterday, Jérôme paid a visit to the layout to run some trains… if we could troubleshoot the short circuit plaguing it. The first hour was spent trying to find out if there was something wrong with the wiring. Could some of the feeders or bus wires be inverted somewhere? Well, we did find two problematic feeders that needed to be moved around, but the problem persisted.

Next, we moved our attention to the staging yard control panel since we got short indication. However, when disconnected from the layout, it was perfectly fine. Using a multimeter, we investigated two Peco curved turnouts. They were electrofrog and could have been insulated incorrectly. Alas, they were fine… I even went so far as removing one, just in case. 

Then Jérôme started to probe the screw connectors. Most of them were shorted, which meant something wrong was going on with the tracks. Pushing forward the investigation, our attention turned to the staging yard lift bridge. Even when disconnected, we got shorts on a few tracks. This would became the focus of our attention.

The problematic situation as discovered

After a while, an idea crossed my mind. Could the soldered PC board ties used at the ends of the bridge be the issue? Well, it was. At first, we suspected solder bridging the gap in the copper foil, but it wasn’t the case. Then, the real problem reared its ugly head. The PC board ties are secured in place with two nails at each end. While the copper foil is notched on top to prevent shorts, the plating under it is continuous. When you drive a metal nail through the tie, it bridges both copper layers, creating short. 

Our solution was to add an insulating notch on top

The solution was easy and I simply removed some copper at one end so the nail could no longer be electrified. In hindsight, I should have notched the copper plating underneat each tie. Once you know the issue, it is extremely easy to remedy, but tracking it took several evenings, and finally two brains. Since I’m not that proficient with electricity, I was suspecting my wiring was wrong, but couldn’t figure out the mistakes. It would have been hard to think the PC board ties were the main issue… or should I say, my way to secure them.

A notch should be made in the bottom copper plating first

With this problem figured out and troubleshooted, I can now complete the basic wiring and start to improve track geometry. I can still see a few things that bother me, including superelevation at turnouts, running noise over plywood and some vertical alignment issues here and there. If I was running only diesel locomotives, I wouldn’t care that much about it. However, large wheelbase steamers don’t like it.