kW. Each running gear is equipped with two motors, which are connected in parallel via their armature circuits. (4-pole separately-excited DC machine with contraflexure poles) Operating voltage 3 x 400 V, 50 Hz Nominal power of motors 4 x 31,5 kW Range of revolutions per minute 0..3290 rpm Nominal torque 90 Nm Nominal propulsive force 8,4 kN Maximum propulsive force 16,8 kN Regular acceleration 1 m/s² Regular deceleration 1 m/s² Emergency deceleration > 1,5 m/s² Nominal speed 13,9 m/s (50 km/h) Positioning accuracy ± 3 cm Noise level (measured at 50 km/h in 25 meter distance) < 65 dB/A Cabin Each cabin is 8.232 metres long (9.20 m, including couplers), 2.244 metres wide and 2.623 metres high. The interior height for standing passengers is 2.003 m. It has two 1.350 m wide automatic sliding doors at each side. The Dortmund cabin provides seating for 16 and standing room for 29 passengers, while the Düsseldorf airport version provides space for 15 and 32, respectively. The cabin shell weighs 4955 kg. The complete car weighs 8455 kg, with bogies weighing 1750 kg each. It can carry a useful load of up to 4923 kg and has a maximum gross weight of 13378 kg. Switching Switching is done with the help of the horizontal guiding wheels, where short blades on both sides of the common section of the carrier move as a canal of the same width as the carrying box to the left or right, while a long blade between the two forking guideways moves right or left to provide the horizontal guidance into the intended direction. History In 1973, the Federal Ministry made DM 22 million (€11,250,000) available for the research and promotion of this system. A test line was opened on 21 July 1975 in Düsseldorf by the former transport minister Hans Matthoefer with a length of 180 metres (approx. 200 yards). In 1976, the system was extended by 1.5 km (a little less than a mile). Dortmund The first publicly funded overhead railway has run since 1984 at the University of Dortmund, where it initially just connected the north and south campuses with a single line. However, many stations have 2 platforms with a track either side permitting carriages to pass each other in opposite directions. This stretch was opened on 2 May 1984 by Dr. Heinz Riesenhuber, and comprised of track and two trains. The cost was approximately