What are Heljan's locomotive wheels made of? Looks like bronze to me. Goodness knows what it is, but they seem to get dirty between one operating session and the next, and require cleaning before the loco will run properly. (I used neat Ecover citrus cleaner and degreaser, and they were good for the whole afternoon.) It's only Heljan wheels that give this trouble, no other manufacturer's wheels do. Why can't they use wheels with nickel plated treads like everyone else?
Does anybody know how I can get at the gearing to lubricate it? I don't want to find after a few hours chasing its tail at 90 m.p.h. with 15 on, that I've stripped a wormwheel or four.