Larger multiple units consisting of two four-axle cars were developed as successors to the railbuses on branch lines. There are several sub-variants, with most vehicles having only one engine in one of the two cars. They were used all over Germany, with the variants with two engines being used more in mountainous regions. Since the turn of the millennium, they have been increasingly replaced by more modern vehicles that have better acceleration and air conditioning. Today, most of the remaining vehicles are used by the Südostbayernbahn in Lower and Upper Bavaria.