The DR locomotive classification scheme in East Germany in the initial post-war period used the DRG system, consisting of a class number (Baureihennummer) followed by a serial number (Ordnungsnummer). With the introduction of computerised (EDP) numbers in 1970 as part of the UIC framework, the system was fundamentally changed for the first time.
In the allocation of operating numbers up to 1970 the Deutsche Bundesbahn and the Deutsche Reichsbahn in East Germany took care, for the most part, to ensure that they did not overlap with one another.