This European Standard describes the railway-specific requirements relating to semi-trailers which are transported by rail with pocket wagons. The semi-trailers shall, for this, be suitable for handling by crane. They are seized by gantry cranes or mobile transhipment equipment by the grappler pockets using grabs and lifted into the pocket wagons. The semi-trailers stand with their wheels on the sunken loading area (pocket) of the wagon and at the front with the fifth-wheel plate on the jack. The king pin is held in the jack and is responsible for the fixing of the semi-trailer in all directions and hence also for withstanding the relevant forces.