To promote the renewal of rolling stock and the standardisation of goods wagons among European state railways, the UIC (Union Internationale de Chemins de Fer) designed two variants of an open goods wagon at the beginning of the 1950s: the UIC Type I and UIC Type II. The UIC Type II closely adhered to the dimensions of 10.0 metres in length with a 5.4-metre wheelbase, drawing strong inspiration from pre-war German designs. The entire frame and wagon body were constructed using welded techniques. Upon completing the detailed design, the Federal Railway began upgrading its O-rolling stock at the Kaiserslautern workshop, using the UIC Type II as a basis. From 1954, 10,589 wagons of the Omm 54 types were produced in Kaiserslautern in just two years. Although officially considered conversions based on usable parts from older wagons, these wagons were largely built from new materials. An exception was the brake components, for which Kkg brakes from donor wagons were utilised. In the subsequent construction batches - designated as Omm 55 - these brakes were also dispensed with and new KE brakes were installed, resulting in the procurement of over 17,300 units from 1955 onwards. Through numerous detailed improvements during production as well as later design changes, the vehicles were maintained throughout their lifecycle and were not completely retired until 1994. In addition to the Federal Railway, other state railways also procured wagons based on the UIC Type II specifications for their fleets. These were deployed by the DR Ost (East German Deutsche Reichsbahn), SNCF, SNCB, FS, MAV, OBB (Austrian Federal Railways), SBB, CSD, DSB and others, each featuring country-specific details or components.
