GERMANY'S third tram-train network following those in Karlsruhe and Saarbrücken has been completed in Kassel with the integration of on-street and local main line running on DB Netz.

Although light rail vehicles began sharing tracks with main line freight trains on the line from Kassel to Baunatal in 1995, a connection between the city centre tram system and the suburban heavy rail network marks the culmination of more than a decade of preparatory work (RG 12.02 p779). Through services started on August 19 with the opening of a tram station at Kassel Hauptbahnhof, which replaces one of the main line platforms.

After the celebrations to open the stop, which is connected with the city tram network via a 117 m long tunnel, commercial services began on RegioTram Line RT4 from the city centre to Wolfhagen. Tram-trains on Line RT4 pass through the tunnel and change running modes at Hauptbahnhof before continuing along DB Netz lines.

Line RT4 uses dual-mode Alstom RegioCitadis cars powered by two 370 kW diesel powerpacks for the non-electrified section between Kassel Hauptbahnhof and Wolfhagen. They switch to a 600 V DC supply to run on the city's tram lines.

Kassel´s RegioTram network already serves 184 route-km across four lines. Only 6 km of new track has been laid, the remainder being either part of the Kassel tramway or the DB Netz network.

Regionalbahn Kassel ordered 28 RegioCitadis cars from Alstom at a cost of €80m under an agreement with the Nordhessische Verkehrsverbund (RG 9.04 p585). There are 10 dual-mode cars, and 18 are dual-system electric taking power at 600 V DC or 15 kV 16·7 Hz AC.