The prototypes of this truck featured one-piece cast sideframes and were used on a wide range of heavyweight equipment. These trucks fit the Walthers (932-series) Heavyweight 12-1 Sleeper, 14-Section Sleeper and 3-2 Observation (all out of production), but adaptable to many other models. An easy upgrade for new and older HO Scale passenger cars, WalthersProto trucks are fully assembled and ready to use with built-in electrical contacts for car lighting and 36" turned metal RP-25 wheels.