Since my trains are all in the basement, which often gets damp, including occasional small puddles on the concrete floor when there's a torrent of rain, I recently bought a dehumidifier.
I believe keeping the basement dry so there's no mildew, among other bad things, and proper use of light oil and gear oil goes along way to keeping everything in good working order. When it's not, I'm out of sorts and either fix it myself or hire my train doctor (he's also Italian and Joshua Lionel Cowen would have hired him in a heartbeat) to fix it.
Arnold
