Metal fully sprung equalized trucks. Mounts with a #2 or 2-56 screw (sold separately). The Bettendorf double truss truck was introduced in the 1930s by U.S. railroads and was allowed to be used in interchange service through 1993. Kadee′s #500, #502 & #550 represent 50-ton trucks for 100,000-pound cars Truck Features: * Code 110 (.110) 33h smooth back wheels * Accurate markings * Incredible detail true to prototype * Non-magnetic metal wheels * Highly flexible sprung trucks * Metal side frames and fully sprung bolster * Smooth tracking free rolling contoured insulated axles * RP-25 free rolling wheels