The → RNV (Rhein-Neckar-Verkehr GmbH)
operates the interconnected tram network of the cities of Mannheim, Ludwigshafen and Heidelberg, including several interurban routes, some of which are dedicated as railway lines, but operated by normal trams. The system length of all lines is more than 300 kilometres.
By 2005, the network had been operated by five different companies (the three municipal transport companies plus the interurban routes operated by Rhein-Haardtbahn GmbH and Oberrheinische Eisenbahn AG). In March 2005, all transport services and vehicles were handed over to the joint venture company RNV.