Prototype: 3 four-axle self-unloading wagons of the German Federal Railroad (DB) type Fad-50 OOtz. Version with two unloading hatches on each long side and a brakeman's platform at the front. Wagons with Minden-Dorstfeld type bogies. Used for transporting goods that are not sensitive to moisture, in this case coke. Operating condition in the 1960s.