Am glad to see that Wahl clipper oil is listed in GRJ's table of non-polar cleaners; I've been using it for some years now.
When I started this thread I was mainly asking about track cars, and there's been some good ones noted. I think however a "train" of track cars, at least 3, pulled by an engine is the magic formula, though am not sure if anything beats the old hand pushing a rag. But, if you can maintain track with cleaning cars, it stands to reason that major cleaning frequency would be reduced.