 Two of these lines connect the Cologne Stadtbahn to the Bonn Stadtbahn.These lines (16 and 18) are jointly operated by both cities' transport authorities, resulting in both systems and the lines connecting them sometimes collectively referred to as "Stadtbahn Rhein-Sieg".The Cologne Stadtbahn is operated by the Kölner Verkehrsbetriebe (KVB) and the Bonn Stadtbahn is operated by the Stadtwerke Bonn (SWB – City of Bonn Utilities Division).