USA Trains claims to have the largest collection of G scale rolling stock in the world.

USA Trains is a family-run business, started by father and son Charles Ro senior and junior.

Charles Ro Supply Company was established in and it started out as a beauty shop business of 4 salons with sixty hair-dressers but moved into the hobby business when Charles Ro, Sr. began selling used Lionel trains at one of the storefronts in Everett, Massachusetts.

To make up for this, Ro began selling German-made large-scale model trains that were suitable for outdoor use.

In 1989, business was moved into a new building, its current location, in Malden, Massachusetts with 3 stories and over 50,000 square feet (4,600 m2) of area.