In the truck (1) the static and dynamic forces are absorbed by the frame (5). In designing the body unit fitted on the frame (5), therefore, only the unit's own weight and the passenger load are significant, thus facilitating the use of extremely lightly-built vehicle bodies. The truck (1) has single-wheel drive units (2), a longitudinal driver (3) interconnecting them, on each long side of a drive (4), the frames (5) bearing the end unit (9) and a drive control (6) for turning the single-wheel drive units (2) horizontally in response to curves. A wheelless central unit (10) is supported on each short side of the truck (1) via a link (8). A push-pull device (7) engages with the short side opposite the link (8). There are no steps, pedestals or shoulders inside the vehicle which is thus freely accessible. In the region of the truck there are recesses in the form of wheel-boxes (9.1) in which certain parts of the truck (1 ) are arranged.

A constant-contact load-bearing assembly for a railcar truck bolster and operable against a complementary body bolster bearing and biased to continuously contact the body-bolster bearing to transfer the lading and railcar weight forces, which assembly has an outer element of a first coefficient of friction, a second or inner element with a second and larger coefficient of friction and biasing apparatus to maintain the inner assembly pad element in contact with the body-bolster assembly at an empty-railcar condition to provide control of the railcar body at the empty or unloaded car status with the biasing apparatus compressible at a loaded railcar state to provide contact between the outer pad element and the body-bolster bearing pad for transfer of the railcar loads and forces over the range of operating loads between the empty-car state and the loaded to capacity state.

A freight railcar undercarriage constant-contact sidebearing arrangement provides a load force transfer mechanism with a more direct or less redundant force transfer path between the railcar body with its lading and the sideframe and wheels of a truck assembly, which system obviates the present use of a bolster center plate structure for load transfer, carries all the load forces through the side bearing assemblies, fulfills the dynamic operating requirements of the American Association of Railroads standards, reduces the weight of the railcar while maintaining the load-carrying capacity, and is particularly adaptable to three-piece truck assemblies in broad use on freight railcars.

A connection between a draft sill and a railway wheel truck is disclosed. The draft sill has a bottom and side walls extending up from the bottom. A center pin extends downward from the bottom to an exterior end surface. A boss encircles the center pin. The boss is attached to the outer surface of the center pin and to the bottom surface of the draft sill. The boss includes a plurality of ribs extending radially outward from the center pin. The total surface area of the horizontal surfaces of the boss and the center pin is less than the surface area of a standard center plate. The horizontal surfaces of the boss and center pin do not bear any vertical load under normal conditions, and no center plate is provided. The center pin and boss can be integral, and can be made to extend upward from the truck bolster to be received in an opening in the draft sill.