Hi George,
Jeff Kane, the Train Tender has been able to supply most of the parts I've needed for my switchers. However, sometimes, one can get lucky... Years ago, I bought the frame/chassis (with drivers, no rods) of one of these 227-series switchers of off eBay really for no reason, just to give it a home. In the end, it became a donor engine for the locomotive I started this topic about. Drivers and idler gears (also on the donor) were in fine shape and able to be swapped.
Tom