@gunrunnerjohn posted:Given the one location and the voltage variation affecting it, I'd look closely at the track and any joints near that location.
I did that. Took up three sections of track, replaced one (rail separated from ties when removed) and replaced all rail joiners. I don't have a functional multi-tester right now. The problem location is two 10-inch track sections from a power feed and occurs at the same and some other locations when running opposite direction. No other locomotive has any such problems on the layout. I think it's the locomotive power pickup or paint on wheel treads. Thanks for responding.
MELGAR