A railway car comprising a longitudinal center sill and floor members carried at opposite sides of the sill, and first locking devices mounted on a cross-bearer connected to the center sill and a second set of locking devices mounted on a second cross-bearer and a third set of locking devices movable...http://www.google.co.uk/patents/US5052868?utm_source=gb-gplus-sharePatent US5052868 - All purpose car
