Abstract

A rolling-stock underframe construction comprising longitudinal side sills, end sills connecting opposite longitudinal ends of one side sills to opposite longitudinal ends of the other side sill, body bolsters respectively disposed at positions corresponding to trucks, and center sills extending between the end sills and the corresponding body bolsters in parallel to the side sills; and a floor member fixedly disposed in an area defined by the side sills and the end sills. The floor member comprises an upper plate forming, a lower plate forming, and a corrugated plate disposed between the upper plate and lower plate. The corrugated plate includes an alternate arrangement of ridges and longitudinal furrows and is joined to both the upper and lower plate. The floor member has weight and thickness smaller than those to join the floor member side sills, and body bolsters, an assembly of the corrugated and the upper plate or lower plate is joined to the side sills and the body bolsters, and then the lower or upper plate is joined to the corrugated plate, the side sills and the body bolsters, so that the floor member is joined firmly to the side sills and the body bolsters.