User:Ajcoxuk/Berlin S-Bahn North South Line

The North-South S-Bahn Tunnel (Nord-Süd-Tunnel in German) is a section of the Berlin S-Bahn under the City-Centre. The title North-South Tunnel is also used for the new Tiergartentunnel, which is used by Intercity and Regional trains. The North-South line encompasses the route from Bornholmer Straße and Gesundbrunnen via Friedrichstraße and Anhalter Bahnhof to Preisterweg (today Südkreuz) and Schöneberg.

The North-South S-Bahn Tunnel has a limited profile (Lichtraumprofil - G2) with a height of 3.83m above the trackhead and a width of 3.43m.

Function
This tunnel originally provided an S-Bahn connection from the former mainline stations of Anhalter Bahnhof and Potsdamer Bahnhof with the interchange for the East-West Stadtbahn at Friedrichstraße and on to Stettiner Bahnhof (today: Nordbahnhof). The tunnel connects three southerly suburban lines (the Wannseebahn from Berlin-Wannsee, the Anhalter Vorortbahn from Teltow and the Dresdener Bahn from Blankenfelde) with three northerly suburban lines (the Kremmener Bahn from Hennigsdorf, the Nordbahn from  Oranienburg and the Stettiner Bahn from Bernau).

Building
After the electrification of the Berlin Stadtbahn, Ringbahn and suburban lines, which was complete in 1933, the need to connect the increasingly popular suburban lines with a link, which at the same time would connect the mainline stations, increased. Because of the crowded inner city, tunnelling was the only solution. Due to the number of underground lines to be crossed, the need to pass under rivers and streams meant that tight curves, small-profile tunnels and steeper inclines than normal were set in the planning parameters.

Building commenced in 1934 with the section from Humboldthain to Unter den Linden being opened on 28th May 1936. The southerly section to Anhalter Bahnhof was opened on the 9th October 1939. It was originally planned to open the entire line in time for the 1936 Summer Olympics, but due to building difficulties (including a serious incident in 1935, when a section of the tunnelling work near the Brandenburger Tor adjacent to the American Embassy collapsed) and numerous plan changes, this was not possible. Between the three northerly and three southern suburban lines, it was envisaged that the new underground station of S-Bahnhof Potsdamer Platz would also provide a curve to the southern section of the Ringbahn.

Due to the planning for the transformation of the Reichshauptstadt this curve was not realised. Instead spurs for a junction to Anhalter Bahnhof were built with the plan for a further underground section to Görlitzer Bahnhof and, south of the Landwehrkanal, four tunnel spurs taking the North-South Line to the planned S-Bahn station Hornstraße.

In addition, a two track preparatory section north of Potsdamer Platz in line with the Brandenburger Tor was built. This was for a later stage for the Great Hall. This section is used today as a storage area. It is planned that this section will be used as part of the S21 line to the new Berlin Hauptbahnhof, then onto the northern section of the Ringbahn. Except for this preparatory work, all other development was halted during World War Two.

Flooding


Shortly before the end of the 2nd World War on 2nd May 1945, the SS almost certainly detonated explosives under the Landwehrkanal. As a result the entire tunnel and (via a connecting tunnel at Friedrichstraße) part of the Berlin Underground network was flooded. There are few other examples in the history of Berlin that have produced so much mythology and half-baked truths. It is controversial whether people were drowned during the flooding, because it is possible these drownings were confused with the 80 to 130 bodies from victims of the last days of the war, who died before the tunnel was flooded.

In the last days of the war, the tunnels were used as an Emergency Hospital. Also controversial (and to this day also unclear) is who actually detonated the tunnel and who had ordered it. In order to cause such an explosion, a very good knowledge of the area and buildings would be required. One theory states that the explosion was part of Hitler's Nero Decree, that was undertaken by members of the SS. There are few eye-witnesses who can actually verify this. Rather they report that in the last days of the war the tunnel was already partially flooded with fresh and sewage water that was leaking from damaged pipes.

Restoration
Although the repairs were began immediately after 1945, the tunnel could not be used until 1947. The S-Bahn lines of the southerly suburban lines first had to be taken back to the overground Potsdamer Bahnhof before, in 1946, it was possible to use the underground line to Anhalter Bahnhof again.

Division of Berlin
With the building of the Berlin Wall in 1961 all the stations in East Berlin were shut, except for Friedrichstraße which was used as a border crossing point. Trains which were now only for use in West Berlin travelled between Anhalter Bahnhof via Friedrichstraße to Humboldthain without stopping. On the evening of 8th January 1984, operation of the section was handed over to the Berliner Verkehrsbetriebe (BVG). The restoration of traffic through the tunnel restarted in May of that year. After the fall of the Berlin Wall all the remaining stations were reopened.

Reunification
With the fall of the Berlin Wall, the previous Ghost Stations were reopened as follows:


 * 2nd July 1990: Oranienburger Straße
 * 1st September 1990: Nordbahnhof, Unter den Linden
 * 22nd December 1990: Bornholmer Straße
 * 1st March 1992: Potsdamer Platz and the complete service following restoration work.

The first comprehensive renovation since 1945 started from January 1991 in sub-sections, but was converted in mid-1991 to a complete closure due to the high levels of dust. The Deutsche Reichsbahn replaced almost all the material in the tunnel walls, then cleaned and recoated them. Hence the wartime flood-damage to the tunnel was finally removed.

The building of the new heavy rail tunnel to the Hauptbahnhof and the connected electromagnetic effects of the overhead wiring meant that a new compatible signalling system had to be installed. This work was undertaken between July 2005 and May 2006. The North-South Line was the last section of the Berlin S-Bahn network to have the automatic Block signalling of type AB 37 and Sv-Signals with aperture relay installed.

Specification
In order for the tunnel to follow the roadway in the heavily built-up city centre, the tightest curve in the North-South Tunnel is only 150m. To operate the trains safely, this required a special profile to be developed for the wheels. The BVG encountered several derailments of its stock which had only a standard wheel profile. The permissible height in the tunnel is also restricted. Therefore trains of type DRG BR ET 169, which have a higher height and longer body, can also not be used in the tunnel. The restrictions in carriage height and length continue to limit the trains that can be used. In particular, trains constructed for other cities cannot be used for the DC S-Bahn system of Berlin.

Stations



 * Humboldthain (above ground but opened with the tunnel section)
 * northerly tunnel entrance at 52.53639°N, 13.38139°W
 * Nordbahnhof (until 1950 Stettiner Bahnhof, the mainline station was disused in 1952 and later demolished)
 * Oranienburger Straße
 * Berlin Friedrichstraße station, with interchange to the Stadtbahn and to the U-Bahn (today line U6).
 * Unter den Linden, at Pariser Platz by the Brandenburger Tor.
 * Potsdamer Platz Bahnhof (the above-ground mainline station was closed in 1945, today the new Mainline Potsdamer Platz station with trains from the new North-South line for Intercity and Regional trains has been opened)
 * Anhalter Bahnhof (the above-ground mainline station was closed in 1952 and demolished in 1960, expect for the station portal).

South of the Anhalter Bahnhof the tunnel divides in two directions for the Wannseebahn (line S1) and the Anhalter/Dresdner Bahn (lines S2 and S25). These two tunnels then surface:
 * southerly tunnel entrance for the Wannseebahn at 52.49556°N, 13.37181°W
 * southerly tunnel entrance for the Dresdener Bahn at 52.49528°N, 13.3725°W

The present subsequent stations of (Yorckstraße and Yorckstraße (Großgörschenstraße)) exist as two separate stations, a couple of hundred metres apart, with separate entrances – although they are today collectively known as Yorckstraße with the Yorckstraße U-Bahn station (U7) running east-west between them.

The architect of most of the stations in the North-South tunnel is Richard Brademann, specifically: Bornholmer Straße, Humboldthain, Oranienburger Straße (Brademann's first S-Bahn Underground station), Unter den Linden, Potsdamer Platz and Anhalter Bahnhof. Stettiner S-Bahnhof had Lüttich as its architect, Friedrichstraße had von Hane. Although they were built in the middle of the National Socialist period, the stations have none of the architecture of National Socialism, rather the officially taboo New Objectivity of the earlier Modern style. Except in a few details, e.g. the mosaic of the emblem in the northern distribution area of S-Bahnhof Potsdamer Platz, with its exit to the New Reich Chancellery, the stations do not follow typical National Socialist Architecture.

The stations were rehabilitated after the fall of the communist government (the Wende) in the light of conservation issues, but important details were not faithfully restored, e.g. the typical station S-Bahn sign outside the station, designed by Richard Brademann, never matched the original. Closest to the original S-Bahn sign are the ones at Anhalter Bahnhof (although instead of the cast iron cutout in the shape of the S-Bahn "S", today they only have a backlit glass screen). During the renovation of Anhalter Bahnhof, the BVG (on behalf of the Senate Construction Administration) attempted to restore the original look of the station and placed enamelled tin plates on the walls. However, in contrast to the original white opaque glass panels, the new ones have completely different light reflections, and instead of white, inconspicuous seams between the panels, the seams reveal a black grid. At Potsdamer Platz they have installed opaque glass panels but have committed other errors: the station labels differ from the Tannenberg Fraktur of the originals, and the letters of the platform-side walls are convex rather than stuck in the shallow etched glass panels. The original pattern can be seen at the Berlin S-Bahn-Museum. There are also labels in the Helvetica font which was until recently used by Deutsche Bahn. During construction of the Regional station, the western part of the distribution hall between the surface and platforms has been cut off. More modern fixtures have also destroyed the original spatial effect.

Since 8th August 2009, in connection with the opening of the interchange with the new U55 line, Unter den Linden has been renamed Brandenburger Tor, although the original name tiles remain on the station walls.

Planning and Development (S21)
In the medium term the North-South tunnel will be further developed with a second North-South section connecting to Hauptbahnhof. This project is being pursued under the planning name of S21 and should improve the currently poor connection of the new Berlin Hauptbahnhof with the North-South S-Bahn line.

This project will proceed in the following stages:
 * In the first stage the new line will divert between the stations of Wedding and Westhafen to a new station at Perleberger Brücke to Hauptbahnhof. This section will allow trains from the Ringbahn to travel to the Hauptbahnhof and then return. It will also allow trains from the northerly suburban lines to travel to and terminate at the Hauptbahnhof.


 * In the second building stage the line would continue through a new station at the Reichstag to the existing station at Potsdamer Platz and therefore allow one of the three North-South S-Bahn lines (and eventually other lines) to travel through the existing North-South tunnel to the new connection via the Hauptbahnhof. This second stage will have relatively high usage as it will provide other parts of the city with a better connection to the Hauptbahnhof.


 * A third section that exists in the thinking of the planners would see a new North-South connection from Potsdamer Platz via a new interchange station at Gleisdreieck (Berlin U-Bahn) and onwards towards Berlin Yorckstraße station (Großgörschenstraße) on the Wanseebahn. The additional usage of this section is limited as there is already a connection at Potsdamer Platz to the U2 Line and at Gleisdreieck only the U1 would be provided with an additional connection.


 * A fourth section would divert from the new North-South connection to the Wannseebahn and then over the reinstated „Cheruskerkurve“ to the southerly part of the Ringbahn.

The building work for the northerly section up to the Hauptbahnhof, which will be funded by the German Federal Government via the Community Transport Financing law, will cost 24 million Euro and be completed between 2011 and 2013. The remaining section should, as envisaged by the financial planning for the Land of Berlin, be built by 2030.

In July 2007 the German Railway announced delays in the construction of the first stage. After they had concluded the financial agreement and thereby delayed the under-signing of the project, the building work would start in 2008, rather than at the end of 2007 as planned.

Some preparatory work has already been completed, including the diversions at the Ringbahn stations of Westhafen and Wedding, the preservation of the route during the building of the Hauptbahnhof and the Tiergartentunnel, along which the new line will run. To the south of the Hauptbahnhof the line will continue either easterly parallel to the U55 or easterly of the Reichstag building and then crossing the U55 to the west of Brandenburger Tor where it will join the old North-South tunnel. South of Potsdamer Platz the new line will divert from the old North-South tunnel and run parallel to the U2 to Gleisdreieck before connect to the existing S-Bahn line at Yorckstraße (Großgörschenstraße). Connections at the north and south ends of Potsdamer Platz station already exist.

Literatur

 * Dr. Michael Braun: Nordsüd-S-Bahn Berlin / 75 Jahre Eisenbahn im Untergrund Herausgeber: Berliner S-Bahn Museum, Verlag: GVE-Verlag, Berlin 2008. ISBN 978-3-89218-112-5