The U4 is a line of the Berlin U-Bahn in Germany, and the second-shortest after the U55 with a length of. It serves five stations, with only the two termini being step-free.
History
In 1903, the then-independent town of Schöneberg, south-west of Berlin, planned to develop an underground railway line to improve public transportation. As the line promised less profit, the negotiations with the former Berliner Hochbahngesellschaft were unsuccessful. Consequently, Schöneberg started to build the line itself on 8 December 1908. Two years later, the construction was finished and, on 1 December 1910, the line was put into operation, as Line BI. Because this line was separate from the pre-existing underground railway, new equipment was required; Schöneberg chose to use tracks and trains compatible with the rest of the fledgeling network, allowing future connections. Although Schöneberg owned the track, upon opening, it handed operations over to the Hochbahngesellschaft. The service depot, located after Innsbrucker Platz station, was expanded in 1926 upon the opening of the U-Bahn platforms of Nollendorfplatz station and was closed in 1932. After World War II a high school was built at the site of the former U4 depot. Nowadays, trains use a spur track that connects line U4 to line U1 where they can access the Warschauer Straße Depot on the latter line. From 1985 until 1993 automatic train operation using the SelTrac system was trialled on line U4. The SelTrac system used on line U4 was manufactured by Standard Elektrik Lorenz, and allowed very tight headways of 50 to 90 seconds.
History
The city of Schöneberg wanted to increase growth, and so decided in 1903 to build an U-Bahn line. There were talks with the Berlin Hochbahngesellschaft. However, the interests of the operator and the city did not match, because the short distance wouldn't bring any profit. So the city of Schöneberg took matters into its own hands and planned the first municipal U-Bahn in Germany. The route was intended as an underground railway from Nollendorfplatz, at which the elevated train station of the Berlin Hoch- und Untergrundbahn was already located, to the hauptstrasse in the south of Schöneberg. An extension to the north was not excluded, even a route to Weissensee was proposed. First, however, the stations Nollendorfplatz, Victoria-Luise-Platz, Bayerischer Platz, Stadtpark and Hauptstrasse planned. South of the station hauptstrasse, the workshop was to be built. Siemens & Halske AEG were given the responsibility of the entire construction, including the equipment of the track and the delivery of the vehicles. All standards were adapted to the already existing Berlin U-Bahn and subway, as in the future a direct connection to the City U-bahn Hochbahngesellschaft was planned. Therefore, the execution of the route was carried out with the dimensions and electrical equipment of the Berlin Kleinprofil network. The groundbreaking ceremony took place on December 8, 1908 in a folk festival-like atmosphere. Next to the construction of the subway was Rudolph Wilde Park, which at that time was called the station Stadtpark. As the park was built on a marshy fens that was up to 30 meters deep, the excavation of the tunnels with a total volume of around 850,000 m³ was used to drain and fill it. After two years of construction, the line was opened on 1 December 1910. However, the festivities were very restrained, as the largest Schöneberg sponsor of the underground, Mayor Rudolph Wilde, had died a month earlier. Since the Schöneberg subway was completely separate from the Berlin network, extra facilities had to be built for this. These included its own wagons and the depot with a workshop. At Nollendorfplatz, a pedestrian tunnel was built between the two stations. South of the station Innsbrucker Platz, the tunnel was continued into Eisackstraße. There was a three - track crossover and parking facility in the tunnel. From the western track, the workshop access line branched off to the workshop, which swung in to a private tunnel to Otzenstraße and reached the daylight on the workshop area. At the end of the tunnel in Otzenstraße, today there is still visible the tunnel exit. At the end of the workshop area there was another short tunnel where the access track ended. The workshop received a five-track wagon hall and a two-track workshop hall. The small Schöneberg workshop was rendered unused with the opening of the new interchange station at Nollendorfplatz in 1926 and therefore decommissioned in 1932, as a permissive vehicle exchange and the achievement of the large workshops of the U-Bahn at the olympic-stadion station and at Warschauer Brucke were possible. On the workshop grounds, the Waldenburg High School was built after the Second World War. The city of Schöneberg was indeed owner and owner of the route, but the operation was run by the Berlin Hochbahngesellschaft. Thus, the different ownership conditions did not matter at all for the passengers, since one day before the opening a collective agreement had been reached. On November 27, 2010, on the occasion of the 100th anniversary of the Schöneberg subway, special traffic with historical rolling stock took place.
