From what i know the Hymek with the old tri-ang hornby bogie in the 70's green was R074, R335 was probably a later ringfield motor version. WHat you have is mid-late 70's. Also yes the wheels are dark by nature when new out of the factory so you've got a quite unrun loco, but a non abrasive clean with lighter fluid should be good with them. If not a small polish with emery board should suffice and they sort of polish themselves by wheel spin on your track. A lovely clean example you have, a little oil it'll go like a dream!
Thanks William. Yes, you are correct - it certainly looks (and feels) like an earlier offering. I rubbed the black off, whacked sone oil on and after a bit of running she goes like a dream. A pity I didn't see about the blackening beforehand and just tried with oil (looked like some crud on there too) but no matter I suppose.
@@Codbotherer it usually wears away after a while on running with a load. Just be sure to use lighter fluid cleaning then rather than abrasive methods, it will make the flange deeper relative to the wheel and it may not run on modern code 100 points. It should be fine as is, especially with Peco
