Until the end of the 1950-ies the DB employed 1960 auxiliary emergency vehicles containing tools and materials, which were engaged in case of accidents such as derailments. These vehicles were reconstructed old coaches. For standardisation purposes the DB then developed jointly with the BZA (Bundesbahnzentralamt), the central design and approval authority of the DB in Minden, a standard support vehicle for emergency services. It was based on the express freight car MDyg and the upper bodies of two auxiliary passenger coaches MCi 43, which were mounted onto two four axle bogies of American design. A total of 100 coaches have been constructed between 1962 and 1966. As from 1969 the lattice side walls were replaced by high density fibre boards. Since era IV the coaches are listed as EHG 388. Except for the livery most of the coaches remained unchanged.