Electrical short debugging

As mentioned earlier today, I discovered an electrical short when testing the newly laid upper tier track. At the time I'd inspected the new track and feeders and didn't find the cause.

This evening I tried again. First I finally cut the rail between the upper tier Auto Reverse (AR) section and the main track. Once done I confirmed that the problem was with the main power district, not any of the three AR sections. Then I very closely inspected all the new track and feeders, including switches, and even moved wires around as a precaution, but still did not find the short.

At that point I began to suspect the track laid earlier for the lower and middle tier. I'd successfully tested that track at the time, but haven't run trains on it for over a month, so there is a decent chance that some of the adjacent construction activities could have caused a short. I cut the power bus wire between the I and J terminals in a way that will allow for easy reconnection. Then I tested and confirmed that the problem is with the older track.

At that point I tested the new track with the SD90/43MAC and everything worked great. The good news here is that all the precautions and applied lessons seem to be resulting in better trackwork, especially the switches.

The bad news is that I still have an electrical short on the old track. I inspected everywhere i could reach and removed several staples to look underneath but found nothing. I'll probably need to remove the upper tier bridge, and in order to do that I'll need to finish the rail cutting for the left side of the bridge.

Hopefully I can resolve tomorrow. If not I can continue work on the upper and middle tiers for at least a while before this electrical short blocks progress.