Before revision: Besides Southern Pacific, the Baltimore & Ohio, Burlington Northern, Denver & Rio Grande Western, Florida East Coast, Illinois Central Railroad , Louisville & Nashville, Milwaukee Road, Missouri Pacific, Penn Central ( Merchants Despatch Transportation), Rock Island Railroad , Seaboard Coast Line, Frisco Railroad , and Southern Railway operated Vert-A-Pacs.
After revision: Besides Southern Pacific, the Baltimore & Ohio, Burlington Northern, Denver & Rio Grande Western, Florida East Coast, Illinois Central Gulf , Louisville & Nashville, Milwaukee Road, Missouri Pacific, Penn Central ( Merchants Despatch Transportation), Rock Island , Seaboard Coast Line, Frisco under , and Southern Railway operated Vert-A-Pacs.