It was recommended long ago by Lewis Polk of Aristo-Craft.
I tried using it as a track cleaner, and it did "break down" all the junk on the rails and wheels on my outdoor G scale loco.
It also reduced friction so locos would not climb grades and made an even dispersal of black goo on all my rails and wheels.
Took a while to clean it off. My recommendation is that it makes rails too slippery, and if you use it, clean it off completely after, and don't get it on your wheels.