Hancock52 posted:Checking out the parts diagram for this tender (listed under the set SKU), it sure looks like there’s a black ground wire connected to the drawbar:
I’d guess that’s your broken connection but why there’d be a ground wire connected to the drawbar I can’t guess. The parts diagram also shows two ground wires from the truck but not where they connect to.
I'll take a shot at this. The loco is an 0-8-0 so there are limited number of flanged wheels actually making contact with the outside rails. In order to ensure the loco has a complete circuit it uses the tender through the drawbar as an extra ground path as a backup.