I was running the layout this afternoon when I got an unexpected short circuit. The layout was being operated at the time using RR&Co automation, with a Lenz set 100 DCC system. The short was due to a train leaving a storage road but its turnout was not set correctly, and hence the train had shorted on the frog. The turnout is operated by a Tortoise motor attached to an NCE Switch-8 with address 120, and the Switch-8 has 8 ports addressed 120-127. I was unable to operate the turnout with the Lenz throttle either, so it's not an automation problem. Checked all the wiring was OK and tried powering off and on, but still no joy. However, turnouts on addresses 121-127 were all OK. As a last resort I put the Switch-8 into setup mode and re-addressed 120, after which all was OK again.
Well for another 5 minutes, that is, until another short occurred at the other end of the layout. Exactly the same symptoms, except that it was a different Switch-8 with addresses 150-157, and 150 was dead until re-addressed.
Now these switch-8s were installed best part of a couple of years ago, and I've not seen this problem before. The DCC track is protected by a PSX but the NCE Switch-8s are on an accessory bus that bypasses the PSX so they should not be affected by track shorts.
Any ideas?