The Postfuhramt in Oranienburger Straße was built to provide suitable stabling for the horses of the growing carriage business. Even before the Postfuhramt, there was a residential building on the same site for postillons, private carters who worked on behalf of the post office. The old building could not cope with the ever-increasing demand for carriages. The first step was to build two two-storey stables, the stagecoach stables, in the courtyard. They could accommodate around 250 horses. The main building housed administrative offices, apartments for postal employees, a post office and a telegraph engineer's office. An extension in the courtyard served as a machine and boiler house for the Berlin pneumatic tube system.