Seconded! The Hob-E-Lube assortment is the last lubes you'll ever need. Teflon, Moly, Graphite, etc and all safe for plastic. Petroleum based lubes will attack plastic and gradually destroy it. The lubes are available separately also.
http://woodlandscenics.woodlandsceni...m/HL650/page/1
ORIGINAL: Panther F
I just picked up some Hob-E-Lube from Hobbytown USA and it's advertised as safe for plastic and paint. Much cheaper than Radio Shack and there's more in the tube.