The turning process lasts 45 seconds and is always carried out without passengers on board. The turntable is remotely operated by the driver from the neighbouring control house. The trolley poles are taken down manually before starting the rotation and are reattached to the trolley wires afterwards, with the aid of so-called "threading tufts".
History
Until 1959, the independent municipality of Burg an der Wupper was connected to the neighbouring cities of Solingen and Remscheid by tram lines 3 and 4. A separate bridge over the Wupper connected the two tram lines. This was destroyed in the Second World War and not rebuilt. Instead, a stub-end terminal was placed on the Solingen side. The tram was shut down in 1959 and replaced by a trolleybus line. The narrow valley of the Wupper did not leave enough space for a turning loop on the -long, but only -wide transfer stop of the tramway. The confined area between the river and a steep slope proved particularly problematic. Therefore, similar to the two above-mentioned turntables in the UK, a circular disc-type surface with a diameter of was alternatively installed for trolleybus line 3 at the time. This was sufficient for the ÜHIIIs trolley type, which was then exclusively used. Originally, the mechanism was manually operated by the driver by means of a hand crank. From 1968 onwards, the problem arose that the new -long wagons of the three-axle Trolleybus Solingen type could not be used on line 3. This was the reason why the long-dated ÜHIIIs vehicles were only used until 27 December 1974, as only when the turntable had an extension attached could it also be used by the TS models. In 1985, it was completely renovated and extended to in diameter. Because of the limited size of the Unterburg turntable, line 683 was the only trolley line in the Solingen network on which no articulated buses could be used. Line 683 was therefore the last line on which the MAN SL 172 HO rigid buses were used. Enlargement of the turntable would only have been possible with great technical and financial expenditure. In the middle of November 2009, line 683 was finally completely converted to modern Swisstrolley articulated vehicles manufactured by Carrosserie Hess. These vehicles have a diesel-powered auxiliary drive with which they operate to and from the :de:Seilbahn Burg|Seilbahn Burgropeway terminal. There, a new bus station was built for line 683 and other bus lines. The former "Burgbrücke" stop, which was located in the short cul-de-sac between Solingerstraße and the turntable, was moved to the other side of the Wupper river.
Future
The Unterburg turntable, which is no longer needed as planned, is to be permanently preserved for special journeys of the Trolleybus Museum. It also benefits from the fact that it was only renovated in the middle of 2004 and thus has a lifespan of ten to fifteen years. A final decision on the future of the world's only remaining trolleybus turntable has, according to SWS, however, not yet fallen.
