Railway divisions in Germany

In Germany and Austria, the running of railway services for a railway administration or the regional network of a large railway company was devolved to railway divisions, variously known as Eisenbahndirektionen (ED), Bundesbahndirektionen (BD) or Reichsbahndirektionen (RBD/Rbd). Their organisation was determined by the railway company concerned or by the state railway and, in the German-speaking lands at least, they formed the intermediate authorities and regional management organisations within the state railway administration's hierarchy.

Source: Wikipedia — Railway divisions in Germany (CC BY-SA 4.0)