I don't know about static buildup because I never have experienced that. It did get me to thinking that since the trolley takes power from an overhead wire and completes the current path to the track rails, I have noticed quite a bit of arcing as the catenary moves along the wire. Talk about dirty transmission conditions and potential for all sorts of electrical stuff going on. I have a way to switch the trolley pickup to just the rails and eliminate some of that arcing. I should try that as a test.

One thing I can say is that the motor current path is run through relay contacts which do not share any current paths with the control circuitry, although they are in close proximity on the control board. Boy I sure hope the problem doesn't come down to isolating the relays in a grounded case since I just re-etched and re-built this version of the board from an earlier version where they were apart.