I have a catalog of track maintenance tools and accessories of 1920's vintage, which shows a wheelbarrow with a double flanged wheel and extra long back legs. This would allow it to be wheeled along one rail. The same catalog also included a side-dump wheelbarrow, a flat one-rail rig with a kick stand like a motorcycle to transport Edison batteries -- at least that's what was on it in the illustration -- and a very primitive one-rail tamper powered by an air compressor. Of course, all these things disappeared 90 years ago!
