USA Trains is a manufacturer of G scale model railroad products that started out as Charles Ro Manufacturing Company. They offer two different scale sizes of trains that use the same track; the "Ultimate Series," which is 1:29 scale, and the "American" and "Work Trains" series which is 1:24 scale. USA Trains claims to have the largest collection of G scale rolling stock in the world. [1] USA Trains was established in 1987.