Wiring question Lionel Legacy Santa Fe #85190 Super Bass B-Unit

That will do it. On many engines those wires go to the pickup rollers. You can use an ohmmeter to verify. They used to use wire nuts to tie the 3rail wires together. You can use electrical tape to cover that exposed wire, more shrink wrap or cut the shrink wrap off and use a wire nut.
Quality control is in the pits these days.

Pete

And there's a reason I love this place! It's not often I get away with the easy fix!

Thanks Pete!!

Update: Sealed off the wire end with a little more shrink wrap. Put it back on the track and bingo, happened again...

Time to go back in and see what else I can find.

I think I may have found out why the previous owner sold the set...

I would start with the pickup rollers. Make sure their travel doesn’t hit the frame or a screw and they are secure.

Pete

Update: There is another small bundle of wires with shrink tube also tucked into the wiring hole to the trucks. Nudged it out, while it did not have a wire protruding like the previous post, it had a wire about 1/16" from the end of the shrink tube. Just enough for it to arc.

Put another piece of tube on, tested it this morning, bingo! Works as it should!!