My Railway being out side in Canada, get a lot of abuse from the elements. I have not found a commercial track that really appeals to me as I think track cleaners should look like purpose built rolling stock, not disguised as something else. So I built two cars, my lite duty single and my heavy duty dual. The bodies are plasma cut from 10 guage steel and welded together. The cleaning pad has a piece of drywall screening slung beneath. Their not pretty but they work.
http://sites.google.com/site/scrapworksrail/Home/track-cleaning-cars