Well, a #4 has about an 18" diverging route and a #6 has about a 24" diverging route. I think a 22" diverging route would be a #5. They aren't common, but you can find them, aprticularly in the Peco and Walthers/Shinohara lines. I know Atlas Customline had a #5 switch at one time, but I don't know if it's in production any longer.