The entire Stadtbahn network uses various colours to differentiate between the main route networks. For example, a station that serves both A and B lines has a blue and a red stripe on its station sign; stop on the D line would feature a lime stripe on the station sign, and so on. This scheme sometimes also recurs in the architecture of the stations, for example Kröpcke station used to feature tiling that changed colour when changing between lines, i.e. yellow elements were introduced in the red tiles when walking from the B to the C part of the station.