Have an Erie 610 switcher locomotive that I bought used on ebay. Intermittently, it just 'buzzes' and doesn't move but after fiddling with the transformer/relay-looking structure in the middle, then seems to 'loosen up' and work. I'm obviously not an expert on this, but seems like it has something to do with the mechanical structure that controls whether the locomotive goes 1 way or 2 directions. Any advice as what to clean or lubricate or replace would be appreciated ...