On my childhood model train layout, there was a large obstacle in the form of a steep ramp to go from one level to the next. Not every engine could climb the hill because of the grade. Now, several years after said layout has been taken apart, I find a solution.
FROG SNOT! You apply a thin coating on a couple of wheels and get an instant boost in traction. If you find the electrical connection is going down, scrape some of it off with a knife. Yet another product to make life easier for those of us who want to model trains without having the time or ability to make a masterpiece in the first go.
If only it were easier to keep them dust-free.