The mushroom concept of the Deutsche Bahn is the operating plan for the railway and S-Bahn routes of the reunified Berlin . It is named after the route of the main routes, which looks like a mushroom on the city map .
As in many other large cities, the railway lines in Berlin ended after their construction in different terminal stations in the city. Already in the 19th century one began to link some of these routes with each other, with
- the connecting line , which already connected the terminal stations in the south at street level in the 1850s,
- the Ringbahn , which runs around the city center, with tracks for S-Bahn and other traffic,
- the light rail , which crosses the city in an east-west direction on a viaduct , also with long-distance and S-Bahn tracks.
In the 1930s the
- North-south tunnel of the S-Bahn, without long-distance railway tracks.
In 1917, the city planner Martin Mächler proposed in a development plan to build a tunnel between Potsdam and Anhalter Bahn and the Lehrter Bahnhof. Above that, building areas should be created to expand the inner city. The Lehrter Bahnhof was to be expanded as a Friedrich List station into a crossing station for north-south and east-west traffic. This model was later to be implemented in a modified form as a mushroom concept .
After the Second World War until the early 1950s, the remaining old terminal stations of Lehrter Bahnhof , Potsdamer Bahnhof , Anhalter Bahnhof , Görlitzer Bahnhof and Stettiner Bahnhof (Nordbahnhof) were shut down because they were badly destroyed and West Berlin was cut off from the surrounding GDR and so on had reduced long-distance traffic. The other terminal stations, such as the Hamburger Bahnhof , were closed as early as the 19th century.
All long-distance traffic in West Berlin was shifted to the light rail route. In East Berlin , in addition to the light rail, the Lichtenberg station has become the most important station and new connections to the north and south. The most important train stations in Berlin on the Stadtbahn route were the Ostbahnhof (until 1950: Schlesischer Bahnhof , from 1987: Hauptbahnhof , since 1998: Ostbahnhof again ) in the east and Zoologischer Garten station in the west.
After the German reunification it became clear that a reorganization of the Berlin railway network was necessary. The Berlin-Lichtenberg train station was too peripheral for large parts of the city, the tram had only limited capacity and there was no long-distance connection to the central areas of the city in north and south directions.
At the beginning of the 1990s, various variants were up for discussion:
- A "ring model" aimed at restoring the previous Berlin railway concept and provided for the expansion of the ring line (partly with four tracks). The north-south traffic should be routed over the inner ring, the east-west traffic mainly over the light rail. With this concept, the trains would have had to stop at several stations in order to guarantee sufficient transfer options.
- The reconstruction of the terminal stations was also proposed, but not taken into account.
- An axis cross model provided intersecting axes and the expansion of the ring line at the Lehrter station. This mushroom concept was developed by DEC from 1991 .
- Another axis cross model examined a central station right in the center of Berlin around Friedrichstrasse station .
When comparing the ring model with the axle box model, experts and Deutsche Reichsbahn certified the axle box model as having advantages over the ring model, particularly in terms of costs and operational implementation.
Decision for the mushroom concept
The Deutsche Reichsbahn and the Berlin Senate opted for the mushroom concept, a modified form of the axis cross model. It was confirmed by the Federal Ministry of Transport on July 15, 1992 and included in the Federal Transport Infrastructure Plan. The forecast total costs up to 2010 were around 20 billion marks in 1994 .
At the request of Deutsche Bahn AG and the State of Berlin (Senate Department for Building and Housing) on September 12, 1995, the Berlin branch of the Federal Railway Authority granted the right to build the "heart" of the new railway concept. This included the main train station, the tunnel for the north-south long-distance railway , the Potsdamer Platz station, the section of the U5 underground line and the relocation of the federal highway 96 . Most of it went into operation with the opening of Berlin Central Station on May 28, 2006.
The operating concept defines on which tracks long-distance and regional trains cross the city and at which stations they stop. When planning the concept, the following criteria were used:
- Travelers to Berlin can easily reach all areas of the city. On the one hand, the long-distance train stations are located at central points in the city and, on the other hand, they are well connected to the city transport network ( local transport ).
- Travelers through Berlin can easily change trains or - if they do not change trains - cross the city quickly.
- As few new tracks and stations as possible are being built and as few new areas as possible (scarce in the center of Berlin) are needed.
The realized concept
The mushroom concept includes the construction of a north-south long-distance line with a 3.5 kilometer long tunnel . This tunnel runs west of the existing S-Bahn tunnel and crosses the light rail on the grounds of the Lehrter station. At this point the new Berlin Central Station was built , which is served by almost all long-distance trains arriving in Berlin.
The new north-south line and the old light rail line form the stem and the brim of the mushroom. The roof is the northern section of the Ringbahn, which directs trains coming from Hamburg to the northern end of the new tunnel, as well as its northwest and northeast sections, which have been expanded for operational purposes. The southern end of the tunnel is directly connected to the line leading to Leipzig . Trains from Rostock and Stralsund are directed into the tunnel from the northeast.
The former Lehrter Bahnhof was the end of the lines from Hamburg and Hanover , which now flow directly into the new central station. South of it and near the former Potsdamer and Anhalter train stations, the new regional train station Potsdamer Platz was built . This is completely underground and has a connection to the north-south S-Bahn and the U2 subway line.
In addition, the following stations have been expanded for long-distance traffic:
- Gesundbrunnen on the northeast ring line for trains in the direction of Mecklenburg and for trains ending in the south
- Spandau in the west outside the ring line for trains in the direction of Hamburg and Hanover
- Südkreuz (until 2006: Papestrasse S-Bahn station ) at the intersection with the southern ring line for trains in the direction of Leipzig and Dresden
For long-distance traffic, the Ostbahnhof remained on the east-west tram route.
In the summer of 2005, the CEO of Deutsche Bahn AG , Hartmut Mehdorn , announced that from May 28, 2006, long-distance trains would no longer stop at Zoo station. Despite massive criticism from traders in the vicinity of the zoo and numerous local politicians, Deutsche Bahn presented its final transport concept for Berlin on July 6, 2005. Contrary to the original mushroom concept agreed with the State of Berlin, the Zoo station lost its status as a long-distance train station.
The expansion of rail node Berlin was - in - subject to a positive business case Federal Transport Infrastructure Plan 1992 as new projects in the priority needs done. The planned total investment was around ten billion marks (price as of January 1, 1991). The project was included in the Federal Railways Expansion Act of November 15, 1993.
By mid-2000, around 6.7 billion of the planned 10.6 billion marks had been built. In 2000 it was planned to limit part of the foreseeable additional costs in the intersection area by saving on the access routes. Commissioning of the newly designed node was planned for 2005. At the end of July 2000, Deutsche Bahn announced that it would postpone commissioning to 2006 in order to save costs and initially only expand the north-south mainline tunnel to two tracks. The expansion of the Papestrasse station and the connection of the Berlin-Dresden railway were postponed. The main station and the north-south route were also scheduled to go into operation in March 2002 for the 2006 World Cup . At the beginning of 2002 the cost of the project was given as around five billion euros.
The company later partly deviated from its earlier plans and put the Südkreuz station and the long-distance railway tunnel (four-track) into operation on May 28, 2006. However, the expansion of the Berlin-Dresdner Bahn in Berlin only began at the end of 2017, with commissioning planned for December 2025.
The overall economic evaluation of the expansion achieved a planned benefit-cost ratio of 1.7. As of December 31, 2005, the total investments realized were 4.1703 billion euros, with a planned total amount of 6.338 billion euros at the end of the project (with connection to BER ). The additional costs are thus 589 million euros.
The effects of the concept can be summarized as follows:
- Long-distance trains traveling through Berlin can stop at several stations and still cross the city directly.
- Every long-distance train stops at the new main station, so you can always change from any line to any other.
- Long-distance and regional traffic is linked at the main train station and the other long-distance stations.
According to the railway, when the north-south tunnel went into operation, the number of daily stops by regional trains in Berlin's urban area increased by around 500 to 1,700. There are 26 stations where you can change trains between regional and S-Bahn trains. The number of passengers traveling in regional traffic rose by three to 44 million passengers in the first year of operation. The travel time reductions are given as up to 35 minutes.
Partly for cost reasons, partly because of other priorities, a number of projects in connection with the mushroom concept were not or only partially implemented.
- The reconstruction of the long-distance tracks of the Dresden Railway in Berlin was delayed. The construction is only to take place after 2014 and with the commissioning of Berlin Brandenburg Airport . Until then, the trains have to take the detour via the Anhalter Bahn and the Berlin outer ring , which means that travel times are not reduced on this route.
- The main line to Potsdam via Zehlendorf was not rebuilt. Only their connection in the tunnel of the north-south long-distance railway was structurally prepared.
- Likewise, the reconstruction of the long-distance tracks of the northern line in Berlin was not necessary. The trains take the detour via the Szczecin Railway and the Berlin outer ring.
- The S-Bahn connection to the main train station in north-south direction was postponed until the second half of the 2010s - construction of the connection called “S21” has now started: in January 2010, construction work began to produce the tunnel shell under Invalidenstrasse .
- The connection of the main station with the underground line 5 in the direction of Alexanderplatz will only be built with a significant delay, with regard to the continuation in the direction of Moabit ( Turmstrasse ) and Charlottenburg ( Jungfernheide ), the planning has been completely postponed. Instead, an extension of the tram route via Turmstrasse and Mierendorffplatz to Luisenplatz or Jungfernheide and Tegel Airport (two branches) is planned.
- The Berlin Gesundbrunnen train station was initially built without a reception building. This was subsequently built and opened in mid-2016.
- During the construction of the main station, the roof of the upper station hall was only shortened for cost reasons and due to scheduling difficulties. Instead of the originally designed roof structure for the lower hall, a simple concrete ceiling was created.
- The construction of a completely new central station and the new tunnel were very costly.
- None of the north-south S-Bahn lines run through the new central station. Such a connection is planned (see S-Bahn Berlin , the space for platforms has been kept free), the northern section has been under construction since autumn 2009. However, the southern part will not be completed before 2023.
- The underground and trams also had to be brought up to the main station. The short underground line U55 to the Brandenburg Gate was opened in August 2009, but the connection between this section and the U5 line does not yet exist. The first line of the tram (M5) only reached the station in December 2014.
- The elimination of the stops of long-distance trains of the Deutsche Bahn in the Zoologischer Garten station was heavily criticized. The deletion of these stops was not part of the original mushroom concept, and many parts of the city are better connected to the Zoologischer Garten station than to the main station.
- Many consider the project to be too large and includes provisions for a significant increase in the number of inhabitants in the agglomeration as well as a change in the modal split in favor of rail transport. Only six trains per hour and direction run through the four-track tunnel. On the other hand, an allegedly insufficient capacity of the tunnel was also criticized.
- Stuttgart 21 - a through station is being built that can be reached by tunnel
- City-Tunnel Leipzig - similar concept without long-distance railway
- Vienna Central Station - two terminal stations will be replaced by a through station
- Belgrade railway junction - central through station with three tunnels in the city and an underground station in the city center
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