The Upper Bavarian Regional Transport authority has configured the vehicles specifically in order to adequately and swiftly negotiate the steep gradients uphill, and safely downhill. The Mercedes-Benz OM 936 Euro VI-compliant engine delivers powerful 260 kW (354 hp). It reaches its maximum torque level, 1400 Nm, from the low speed of 1200 rpm. Its 4-speed automatic transmission was specifically adapted to the Kehlstein line. It operates with an overall ratio of 6.21, the ratio of the lower gears taking the topographic particularities of the line fully into account, and with a significantly enhanced retarder performance for driving downhill.
The Citaro Ü, painted in traffic red, also does justice to the demands made by the great number of passengers. Two electrically-operated pivot-and-slide doors ensure a swift, smooth passenger flow and allow additional space in the interior for seats as well as a wheelchair area. All the passengers must be seated before the steep mountain road can be tackled. Passenger compartment and driver's workstation are each tempered by their own separate roof-mounted air conditioning systems.
Since 1 June, 1976 the Kehlstein route is served by RVO, (Regionalverkehr Oberbayern GmbH), the Upper Bavarian Regional Transport authority (German Railways, Upper Bavarian Bus) on behalf of the Berchtesgaden-Königssee Tourist Region (Tourismusregion Berchtesgaden-Königssee TRBK). Using a sophisticated system, the traffic manager controls operations, to ensure that some 300,000 visitors can use this the highest bus line in Germany. Travel time to the Kehlstein is around 15 minutes.