Originally about 150 heating boiler wagons made in Prussia were in service during the Epochs I-III. These special wagons were necessary due to the fact that longer passenger trains could not be sufficiently heated by the heating capacity of the locomotives when it was very cold outside. Especially the passengers in the wagons that were further back were suffering. Heating boiler wagons were not only in service for the steam locomotives but also on electrified railway lines. The service of heating boiler wagons ended at the DB around 1965 whereas at the DR the wagons were still in full use until the years 1975 and 1976. With interior decoration and moveable sliding doors. Model with smoke generator. Equipped with a function decoder. Usable for analogue and digital operation.