I have the full set of Fox Valley NS Heritage GEVOs and have been generally happy. Like the detail, easy decoder install, and operation has been good. Developed a problem with a couple of them (I do put a lot of run time on locomotives) that was driving me crazy -- intermittent contact problems. The problem locos would run fine, then start doing the hesitation shuffle. I disassembled them and cleaned everything, inspected everything (I thought), tried various tricks -- including Mike Fifer's using Kapton tape to keep contact strips in place (taping the contact strips aft of the forward trucks and forward of the aft trucks). Having seen an old post somewhere about wipers wearing, I disassembled trucks and used an ultrasonic cleaner on the wipers. Still no resolution. FINALLY, I disassembled trucks again when I noticed it appeared that the wipers might be warped toward the ends, i.e., having a tighter fit in the middle than the ends. SLIGHTLY bent the wipers toward the ends to tighten the fit with the front and rear wheels of each truck and it seems to have worked. Both problem locomotives are back to consistently crawling through turnouts and I am as happy as when they came out of the case new. Don't know if I caused the problem, but thought I'd share the solution.
