I got my N scale RSD4 out of storage for a test run on the Arklatex Sub, and boy o boy- it sounded like a coffee grinder! A bit jerky-moving, too....... I'm probably asking silly questions here, but any hints on how to reduce the sound & improve the operation? I've already cleaned the gunk off the wheels using isopropyl alcohol, and got quite a bit of crap off, but now I have the noise- sounds like it's gonna throw a rod. How do I fix this?