On my C420s most of the pickups (wires from the wheels) have been burned away – how do I replace them and with what – so that it doesn’t happen again?
Also most of the wheels were slightly out of gauge from the factory
When I replaced those brass wheel-sets with nickel silver ones, I bent new pick-up wires from the same gauge piano wire as the originals and soldered a flexible wire to the top of each pick-up for good contact.
Walthers offers phosfer-bronze wire in different gauges. This is a better choice than steel wire or brass, it’s springy and doesn’t corrode.
You could also try a Rivarossi service center (I’ve seen a couple mentioned here on the forum) and get the actual replacement parts if they’re available. Rivarossi bought out Lima a few years ago nad that included the C-420 which they also updated with a new slower motor (rather than having to produce new gears) to make it more compatable with other locos, (they probably didn’t want to continue buying those nice Mashima motors). BTW, the new motor is a drop in replacement.