Editing West Berlin (section)

==Transport and transit travel==
West Berliners could travel to West Germany and all Western and [[Non-Aligned Movement|non-aligned]] states at all times, except during the [[Berlin Blockade]] by the Soviet Union (24 June 1948 to 12 May 1949) when there were restrictions on passenger flight capacity imposed by the airlift.

Travelling to and from West Berlin by road or train always required passing through East German border checks, since West Berlin was an [[enclave]] surrounded by East Germany and East Berlin. On 2 October 1967, six years after the Wall was constructed, tram tracks in West Berlin were removed because the authorities wanted to promote car usage, meaning that the tram system remaining today runs almost entirely within the former East Berlin.<ref>[http://www.the-berlin-wall.com/videos/the-tram-disappears-from-west-berlin-575/ The tram disappears from West-Berlin – The Berlin Wall] {{Webarchive|url=https://web.archive.org/web/20170922143351/https://www.the-berlin-wall.com/videos/the-tram-disappears-from-west-berlin-575/ |date=22 September 2017 }}, [[Rundfunk Berlin-Brandenburg|RBB]]</ref>

===Road traffic===
As there were no dedicated walled-off-road corridors between West Germany and West Berlin under West German jurisdiction, travellers needed to pass through East Germany. A valid passport was required for citizens of West Germany and other western nationals to be produced at East German border checks. West Berliners could get admission only through their identity cards (see above). For travel from West Berlin to Denmark, Sweden and West Germany via dedicated East German transit routes ({{langx|de|link=no|Transitstrecke}}), East German border guards issued a ''transit visa'' for a fee of 5 [[Deutsche Mark|Western Deutsche Mark]]. For journeys between West Berlin and [[People's Republic of Poland|Poland]] or [[Czechoslovakia]] through East Germany, each traveller was also required to present a valid visa for the destination country.<ref>{{Cite book |last=Major |first=Patrick |url=https://www.worldcat.org/oclc/516290074 |title=Behind the Berlin Wall : East Germany and the frontiers of power |date=2010 |publisher=Oxford University Press |isbn=978-0-19-156753-7 |location=Oxford |pages=29, 105 |oclc=516290074}}</ref>

The transit routes for road travel connecting West Berlin to other destinations usually consisted of [[autobahn]]s and other highways, marked by ''Transit'' signs. ''Transit travellers'' ({{langx|de|link=no|Transitreisende}}) were prohibited to leave the transit routes, and occasional traffic checkpoints would check for violators.

There were four transit routes between West Berlin and West Germany:
*One between West Berlin's ''Heerstraße'' with the East German checkpoint in [[Dallgow-Döberitz|Dallgow]] until 1951, then replaced by [[Staaken]] for destinations in [[Northern Germany]] (originally via highway ''[[Bundesstraße 5|F 5]]'') at the Eastern checkpoint in Horst (a part of today's [[Nostorf]]) and the Western [[Lauenburg/Elbe|Lauenburg upon Elbe]]. These were replaced on 20 November 1982 by a new autobahn crossing at [[Zarrentin]] (E)/[[Gudow]] (W).<ref>According to the German-German ''Traffic Agreement'' of 29 November 1978, the transit via highway ''F 5'' was replaced by a new autobahn connecting Hamburg with [[Wittstock]] (today's [[Bundesautobahn 24|A 24]]), from there on using the existing autobahn between Berlin and [[Rostock]] (today's [[Bundesautobahn 19|A 19]]). The West German ''Federal Government'' paid DM 1.2 billion to co-finance the construction of these roads. East Germany, in chronic need of [[foreign exchange reserves|western foreign currencies]], often showed cooperation whenever Western payments were involved.</ref> On 1 January 1988, the new Stolpe checkpoint opened on this route to West Berlin. This is part of today's [[Hohen Neuendorf]] (E)/Berlin-[[Heiligensee]] (W).{{citation needed|reason=|date=August 2015}}
*A second transit route led to Northwestern and [[Western Germany]] – following today's [[Bundesautobahn 2|A 2]] – crossing the [[inner German border]] at [[Helmstedt-Marienborn border crossing|Marienborn]] (E)/[[Helmstedt]] (W), also called ''Checkpoint Alpha''.
*A third route to Southwestern Germany consisted of today's [[Bundesautobahn 9|A 9]] and [[Bundesautobahn 4|A 4]] with border crossing at [[Wartha (Eisenach)|Wartha]] (E)/[[Herleshausen]] (W).<ref>{{Cite web |last=UrbEx-NL |date=2008-03-23 |title=Abandoned and Lost Places - Checkpoint Alpha: Grenzübergangsstelle Marienborn |url=https://www.urbex.nl/checkpoint-alpha-grenzubergangsstelle-marienborn/ |access-date=2024-07-13 |website=Abandoned and Lost Places |language=en-US}}</ref>
*A fourth (via today's A 9) to [[Southern Germany]] had border crossings originally at [[Juchhöh|Mount Juchhöh]] (E)/[[Töpen]] (W) and later at [[Hirschberg, Thuringia|Hirschberg upon Saale]] (E)/ Rudolphstein (a part of today's [[Berg, Upper Franconia|Berg in Upper Franconia]]) (W).{{citation needed|reason=|date=August 2015}}
[[File:Bundesarchiv Bild 183-L0331-0009, Potsdam, Grenzübergang Drewitz-Dreilinden, Verplomben von LKW.jpg|thumb|right|East German border crossing Potsdam-Drewitz on 31 March 1972: Applying eastern lead seals to western trucks, entering the transit route, in order to prevent potential Eastern German escapees from hiding in the cargo space]]

The latter three routes used autobahns built during the [[Nazi Germany|Nazi]] era. They left West Berlin at ''Checkpoint Dreilinden'', also called [[Checkpoint Bravo]] (W)/[[Potsdam]]-Drewitz (E). Transit routes to Poland were via today's [[Bundesautobahn 11|A 11]] to [[Nadrensee]]-Pomellen (East Germany, GDR)/[[Kołbaskowo|Kołbaskowo (Kolbitzow)]] (PL), eastwards via today's [[Bundesautobahn 12|A 12]] to [[Frankfurt (Oder)|Frankfurt upon Oder]] (GDR)/[[Słubice]] (PL), or southeastwards via today's [[Bundesautobahn 13|A 13]] and [[Bundesautobahn 15|A 15]] to [[Forst (Lausitz)|Forst in Lusatia/Baršć]] (GDR)/[[Zasieki|Zasieki (Berge)]] (PL). Additional routes led to Denmark and Sweden by ferry between Warnemünde (GDR) and [[Gedser]] (DK) and by ferry between [[Sassnitz]] (GDR) and [[Rønne]] (DK) or [[Trelleborg]] (S). Routes to Czechoslovakia were via [[Schmilka]] (GDR)/[[Hřensko|Hřensko (Herrnskretschen)]] (ČSSR) and via Fürstenau (a part of today's [[Geising]]) (GDR)/[[Cínovec|Cínovec (Cinvald/Böhmisch Zinnwald)]] (ČSSR).

The transit routes were also used for East German domestic traffic. This meant that transit passengers could potentially meet with East Germans and East Berliners at restaurants at motorway rest stops. Since such meetings were deemed illegal by the East German government, border guards would calculate the travel duration from the time of entry and exit of the transit route. Excessive time spent for transit travel could arouse their suspicion and prompt questioning or additional checking by the border guards. Western [[Coach (vehicle)|coach]]es could stop only at dedicated service areas since the East German government was concerned that East Germans might potentially use coaches to escape into the West.<ref>{{Cite web |last=Colitt |first=Leslie |date=16 August 2011 |title=Escape from East Berlin |url=http://www.theguardian.com/world/2011/aug/16/escape-from-east-berlin |access-date=9 May 2022 |website=The Guardian|archive-date=9 May 2022 |archive-url=https://web.archive.org/web/20220509094518/https://www.theguardian.com/world/2011/aug/16/escape-from-east-berlin |url-status=live }}</ref>

On 1 September 1951, East Germany, because of a shortage in [[foreign exchange reserves|foreign currencies]], started to levy road tolls on cars using the transit routes. At first, the toll amounted to 10 [[East German mark|Ostmark]] per passenger car and 10 to 50 for trucks, depending on size.{{citation needed|date=December 2023}} Ostmarks had to be exchanged into Deutsche Mark at a rate of 1:1. On 30 March 1955, East Germany raised the toll for passenger cars to 30 Deutsche Marks, but after West German protests, in June of the same year, it changed it back to the previous rate.{{citation needed|date=December 2023}}

===Railway===
Four transit train connections—earlier also called ''interzonal train'' ({{langx|de|link=no|Interzonenzug}})—connected West Berlin with [[Hamburg Hbf|Hamburg]] via [[Schwanheide station|Schwanheide]] (E)/[[Büchen station|Büchen]] (W) in the North, with [[Hanover]] via [[Marienborn station|Marienborn]] (E)/[[Helmstedt station|Helmstedt]] (W) in the West, with [[Frankfurt (Main)|Frankfurt am Main]] via [[Gerstungen station|Gerstungen]] (E)/[[Wildeck|Hönebach]] (W) in the Southwest, and with [[Nürnberg Hauptbahnhof|Nuremberg]] via [[Probstzella station|Probstzella]] (E)/[[Ludwigsstadt station|Ludwigsstadt]] (W) in the South of West Germany. These transit trains did not service domestic passengers of East Germany and made stops in East Germany almost exclusively for East German border guards upon entering and leaving the country. Until the construction of the Berlin Wall, ''interzonal trains'' would also stop once on their way within East Germany for travellers having a visa for entering or leaving East Germany. Train travel from West Berlin to Czechoslovakia, Denmark (by ferry), Poland and Sweden (by ferry) required a visa to enter East Berlin or East Germany to allow transfer to an international train—which also carried domestic passengers—bound for an international destination. One railway connection between West Berlin and [[Oebisfelde station|Oebisfelde]] (E)/[[Wolfsburg Hauptbahnhof|Wolfsburg]] (W) was reserved for freight trains only.{{citation needed|reason=|date=August 2015}}

In July and August 1945, the three Western Allies and the Soviet Union decided that the railways, previously serviced by the [[Deutsche Reichsbahn]] (German Reich Railways), should continue to be operated by one railway administration to service all four sectors. West Berlin had – with the exception of a few small private railway lines – no separate railway administration. Furthermore, the operation of the Reichsbahn's [[Berlin S-Bahn]] electric metropolitan transport network, consisting of commuter trains, was also maintained. After the founding of East Germany on 7 October 1949 it gained responsibility for the Reichsbahn in its territory. East Germany continued to run its railways under the official name [[Deutsche Reichsbahn (East Germany)|Deutsche Reichsbahn]], which thus maintained responsibility for almost all railway transport in all four sectors of Berlin.<ref>This explains the retaining of the name "Deutsche Reichsbahn" despite containing the word "Reich" (Nation or Empire) replaced in the names of all other institutions taken over by the communist GDR.</ref> The GDR-controlled 'Bahnpolizei', the Reichsbahn's railway police, were authorised to patrol station premises and other railway property in the whole city including West Berlin.{{citation needed|reason=|date=August 2015}} The legal necessity of keeping the term 'Deutsche Reichsbahn' explains the surprising use of the word 'Reich' (with its Imperial and Nazi connotations) in the name of an official organisation of the communist GDR.

After the Berlin Blockade ''transit trains'' ({{langx|de|link=no|Transitzüge}}) would leave and enter West Berlin only via one line through [[Berlin-Wannsee railway station]] (W) and [[Potsdam Griebnitzsee railway station]] (E). All transit trains would start or end in East Berlin, passing through West Berlin with only one stop in the Western [[Berlin Zoologischer Garten railway station]], which became West Berlin's main railway station. Until 1952, the Reichsbahn also permitted stops at other stations on the way through the Western sectors.{{citation needed|date=December 2023}}<ref>{{Cite web |last=Merrill |first=Samuel |date=October 15, 2015 |title=Identities in transit: The (re)connections and (re)brandings of Berlin's municipal railway infrastructure after 1989 |url=https://www.researchgate.net/publication/282768097 |access-date=March 3, 2025 |website=ResearchGate}}</ref>

Many Reichsbahn employees working in West Berlin were West Berliners. Their East German employer, whose proceeds from ticket sales for Western Deutsche Marks contributed to East Germany's foreign revenues, tried to hold down wage [[social security]] contributions in Western Deutsche Mark. Therefore, West Berlin employees of the Reichsbahn were paid partly in Eastern German currency. They could spend this money in East Germany and take their purchases to West Berlin, which other Westerners could not do to the same extent. West Berlin employees were trained in East Germany and employed under East German labour laws.<ref>This was felt in 1980. The Reichsbahn tried to reduce its losses from operating West Berlin's S-Bahns by reducing the staff and the operation time in the evenings and nights, further reducing the salaries of the remaining employees. Being paid worse than West German railway workers, the West Berlin S-Bahn employees went on strike, which was legal in capitalist West Berlin, but illegal in communist East Berlin, because it was regarded as disloyalty to the communist party. The strikers occupied the signal towers, blocking any rail traffic in West Berlin as of 20 September. With the help of Soviet patrollers in West Berlin, East German railway workers recaptured the signal towers and other railway premises on 22 September. More than 200 West Berlin Reichsbahn employees who did not return to work were then dismissed. This was illegal under West Berlin law, because going on strike there does not provide legal grounds for a dismissal. However, as the Reichsbahn was out of western jurisdiction, the West Berlin government provided payment of unemployment benefits to the former Reichsbahn workers, despite the Reichsbahn never having paid contributions to the unemployment insurance fund in West Berlin.</ref> West Berliners employed by the Reichsbahn were not included in the Western health insurance system either. The Reichsbahn ran its own hospital for them in West Berlin, the building of which is now used as the headquarters of [[Bombardier Transportation]]. For certain patients, the Reichsbahn would facilitate treatment in a hospital in East Berlin. In medical emergencies, the employees could use West Berlin doctors and hospitals, which would then be paid for by the Reichsbahn.{{citation needed|reason=|date=August 2015}}

The GDR used the western stations to distribute propaganda and display posters with slogans like "Americans Go Home." On 1 May, May Day, a state holiday in East and West, S-Bahn trains were sometimes decorated with the East German banner and a red flag.

===Waterways===
Two waterways via the rivers and canals [[Havel]] and [[Mittellandkanal]] were open for [[inland navigation]], but only freight vessels were allowed to cross from West Berlin into East German waters. The Havel crossed at the East German border in Nedlitz (a part of [[Bornstedt (Potsdam)|Potsdam-Bornstedt]]), continuing through the [[Elbe-Havel Canal]] and then either taking the [[Elbe]] northwestwards crossing the border again at [[Cumlosen]] (E)/[[Schnackenburg]] (W) or westwards following the Mittellandkanal to Buchhorst (Oebisfelde) (E)/Rühen (W). Western freight vessels could stop only at dedicated service areas, because the East German government wanted to prevent any East Germans from boarding them.

In July and August 1945, the Western Allies and the Soviet Union decided that the operation and maintenance of the waterways and locks, which were previously run by the national German directorate for inland navigation ({{langx|de|[[:de:Wasser- und Schifffahrtsamt Berlin|Wasser- und Schifffahrtsamt Berlin]]}}), should be continued and reconstructed in all four sectors.<ref name="Karwelat 1984 5">Jürgen Karwelat, ''Passagen: Geschichte am Landwehrkanal'', Berliner Geschichtswerkstatt (ed.), Berlin: no publ., 1984, p. 5. No ISBN.</ref> Except for the originally city-owned [[Neukölln Ship Canal]] and some canals built later (e.g. [[Westhafen Canal]]) and locks, West Berlin had no separate inland navigation authority, but the East Berlin-based authority operated most waterways and locks, their lockmasters employed by the East.<ref name="Karwelat 1984 5"/> Because of their negligent maintenance, the western Allies later transferred their control to the Senate of Berlin (West).<ref name="Karwelat 1984 6">Jürgen Karwelat, ''Passagen: Geschichte am Landwehrkanal'', Berliner Geschichtswerkstatt (ed.), Berlin: no publ., 1984, p. 6. No ISBN.</ref>

The western entrance to the [[Teltowkanal]], connecting several industrial areas of West Berlin for heavy freight transport, was blocked by East Germany in Potsdam-[[Glienicke Bridge|Klein Glienicke]]. Therefore, vessels going to the Teltowkanal had to take a detour via the river [[Spree (river)|Spree]] through West and East Berlin's city centre to enter the canal from the East. On 20 November 1981, East Germany reopened the western entrance, which required two more vessel border checkpoints – Dreilinden and [[Kleinmachnow]] – because the waterway crossed the border between East Germany and West Berlin four times.{{citation needed|date=December 2023}}

===Air traffic===
[[File:Avro York - Bundesarchiv B 145 Bild-P004762, Berlin-Tempelhof, Flüchtlinge.jpg|thumb|right|Eastern refugees boarding an [[Avro York]] at [[Tempelhof Central Airport|Tempelhof Airport]] to fly into West Germany, 1953]] 
Air traffic was the only connection between West Berlin and the Western world that was not directly under East German control. On 4 July 1948, [[British European Airways]] opened the first regular service for civilians between West Berlin and Hamburg.<ref>Foreign Commerce Weekly. United States, U.S. Department of Commerce, 1949. 36-37, page 36

https://www.google.co.uk/books/edition/Foreign_Commerce_Weekly/5AAiAQAAMAAJ?hl=en&gbpv=0</ref> Tickets were originally sold for [[pound sterling|pounds sterling]] only.{{citation needed|date=April 2011}} West Berliners and West Germans who had earlier fled East Germany or East Berlin, and thus could face imprisonment on entering East Germany or East Berlin, could only take flights for travel to and from West Berlin.<ref>East Germany required East Germans and East Berliners wishing to leave the country to get exit permission first. However, permission was usually denied, and leaving the country without permission was [[Republikflucht]], considered a criminal act by the East German justice system.</ref> To enable individuals threatened by East German imprisonment to fly to and from West Berlin the West German government subsidised the flights.{{citation needed|reason=|date=August 2015}}

Flights between West Germany and West Berlin were under Allied control by the quadripartite [[Berlin Air Safety Centre]]. According to permanent agreements, three [[West Berlin Air Corridor|air corridors]] to West Germany were provided, which were open only for British, French, or U.S. military planes or civilian planes registered with companies in those countries.{{citation needed|reason=|date=August 2015}}

The airspace controlled by the ''Berlin Air Safety Center'' comprised a radius of {{cvt|20|mi|km|order=flip}} around the seat of the center in the [[Kammergericht]] building in Berlin-[[Schöneberg]] – thus covering most of East and West Berlin and the three corridors, of the same width – one northwestwards to Hamburg ([[Fuhlsbüttel Airport]]), one westwards to Hanover, and one southwestwards to Frankfurt upon Main ([[Rhein-Main Air Base]]).

The West German airline [[Lufthansa]] and most other international airlines were not permitted to fly to West Berlin. Flights by Lufthansa or the East German airline [[Interflug]] servicing connections between East and West Germany (such as between [[Düsseldorf]] and Hamburg in West Germany and the East German city of [[Leipzig]]) began in August 1989, but these routes had to go through Czechoslovak or Danish airspace.{{citation needed|reason=|date=August 2015}}

===Traffic between West Berlin and East Germany===
Until 1953, travelling from West Berlin into East Germany ([[German Democratic Republic]] (GDR)) fell under [[Interzonal traffic]] regulations overseen by the three Allied military governments (the [[Soviet Military Administration in Germany|Soviet Military Administration in Germany (SVAG)]], the [[Control Commission for Germany – British Element]], and the [[Office of Military Government, United States|Office of Military Government/United States (OMGUS)]]). On 27 May 1952, East Germany closed its border with West Germany and its {{cvt|115|km|mi|adj=on}}-long border with West Berlin. From then on West Berliners required a permit to enter East Germany. East German border checkpoints were established in East German suburbs of West Berlin, and most streets were gradually closed for interzonal travel into East Germany. The last checkpoint to remain open was located at the [[Glienicker Brücke]] near Potsdam, until it was also closed by East Germany on 3 July 1953. The checkpoint at Staaken's Heerstraße remained open only for transit traffic to West Germany.{{citation needed|reason=|date=August 2015}}
[[File:BerlinerBlockadeLuftwege.png|thumb|left|300px|The only three permissible [[West Berlin Air Corridor]]s]]

This caused hardship for many West Berlin residents, especially those who had friends and family in East Germany. However, East Germans could still enter West Berlin. A number of cemeteries located in East Germany were also affected by the closure. Many church congregations in Berlin owned cemeteries outside the city, so many West Berlin congregations had cemeteries that were located in East Germany. For example, the ''Friedhof vor Charlottenburg'' (in ''Cemetery in front/outside of Charlottenburg'') was located in the East German suburb of [[Dallgow-Döberitz|Dallgow]], yet belonged to Catholic congregations in Berlin-[[Charlottenburg]]. Many West Berliners wishing to visit the grave of a relative or friend on cemeteries located in East Germany were now unable to do so. Until 1961, East Germany occasionally issued permits to West Berliners to visit the cemeteries on the Catholic feast of ''All Saints'' on 1 November and on the Protestant [[Buß- und Bettag|Day of Repentance and Prayer]].{{citation needed|reason=|date=August 2015}}

In 1948–1952, the Reichsbahn connected the western suburbs of West Berlin to its S-Bahn network. Train routes servicing these suburbs formerly went through West Berlin stations, but ceased to make stops in the western stations or terminated service before entering West Berlin. Private West Berlin railway lines like the [[Neukölln–Mittenwalde railway]] (Neukölln-Mittenwalder Eisenbahn, NME), connecting the East German [[Mittenwalde]] with West Berlin-[[Neukölln]] and the ''Bötzowbahn'' between West Berlin-[[Spandau]] and East German [[Hennigsdorf]], were disrupted at the border between West Berlin and East Germany on 26 October 1948 and August 1950, respectively.

Tramways and bus routes that connected West Berlin with its East German suburbs and were operated by West Berlin's public transport operator [[Berliner Verkehrsbetriebe|Berliner Verkehrsbetriebe Gesellschaft (''BVG'' West)]] ceased operation on 14 October 1950, after West Berlin tram and bus drivers had been repeatedly stopped and arrested by East German police for having western currency on them, considered a crime in the East.<ref name="BVG">Cf. [http://home.arcor.de/boerge74/stadtbahn/text/tram/text/ausserhalb.html "BVG-Straßenbahnlinien außerhalb Berlins (Linien 47 und 96)"] {{Webarchive|url=https://web.archive.org/web/20130523173244/http://home.arcor.de/boerge74/stadtbahn/text/tram/text/ausserhalb.html |date=23 May 2013 }}, on: [http://home.arcor.de/boerge74/stadtbahn/ ''Öffentlicher Nahverkehr in Berlin''] {{Webarchive|url=https://web.archive.org/web/20130523160428/http://home.arcor.de/boerge74/stadtbahn/ |date=23 May 2013 }}, retrieved on 2 May 2012.</ref> The BVG (West) terminated route sections that extended into East Germany, like the southern end of tram line 47 to [[Schönefeld, Brandenburg|Schönefeld]], the southwestern end of tram line 96 to [[Kleinmachnow]], as well as two bus lines to [[Glienicke/Nordbahn|Glienicke at the Nordbahn]], north, and to [[Falkensee]], northwest of West Berlin.<ref name="BVG"/> The East German section of tram line 96 continued operating with eastern personnel and cars, obliging the eastern passengers – rarely westerners who needed special permits to enter East Germany – to change from eastern into western trains crossing the border by foot, until it was closed by the Wall.<ref>[http://hahn-homepage.de/index.php/initiativen/linie-96/ "Linie 96, 2009"] {{Webarchive|url=https://web.archive.org/web/20130625080822/http://hahn-homepage.de/index.php/initiativen/linie-96/ |date=25 June 2013 }}, on: [http://hahn-homepage.de/ ''Peter Hahn''] {{Webarchive|url=https://web.archive.org/web/20120304152854/http://hahn-homepage.de/ |date=4 March 2012 }}, retrieved on 2 May 2012.</ref>

The Reichsbahn shut down all of its West Berlin terminal stations and redirected its trains to stations in East Berlin, starting with [[Berlin Görlitzer Bahnhof]] – closed on 29 April 1951 – before serving rail traffic with [[Görlitz]] and the southeast of East Germany. On 28 August 1951, trains usually serving [[Lehrter Bahnhof|Berlin Lehrter Bahnhof]] were redirected to stations in East Berlin, while trains from West Germany were redirected to the Western ''Berlin Zoologischer Garten''. The Reichsbahn also closed down both [[Berlin Anhalter Bahnhof]] and [[Berlin Nordbahnhof]], on 18 May 1952.<ref>{{Cite web |title=History of S-Bahn Berlin |url=https://sbahn.berlin/en/about-us/company-profile/history-of-s-bahn-berlin/ |access-date=28 April 2022 |website=sbahn.berlin|archive-date=21 September 2018 |archive-url=https://web.archive.org/web/20180921191222/https://sbahn.berlin/en/about-us/company-profile/history-of-s-bahn-berlin/ |url-status=live }}</ref>

On 28 August 1951, the Reichsbahn opened a new connection – from Spandau via [[Berlin Jungfernheide station]] – for the S-Bahn lines connecting East German suburbs to the west of West Berlin (namely Falkensee, Staaken) with East Berlin, thus circumventing the centre of West Berlin. In June 1953, the Reichsbahn further cut off West Berlin from its East German suburbs by the introduction of additional ''express S-Bahn trains'' ({{langx|de|link=no|Durchläufer}}). These routes originated from several East German suburbs bordering West Berlin (such as Falkensee, Potsdam, [[Oranienburg]], Staaken, and [[Velten]]), crossing West Berlin non-stop until reaching its destinations in East Berlin. However, the regular S-Bahn connections with West Berlin's East German suburbs, stopping at every Western station, continued. From 17 June to 9 July 1953, East Germany blocked off all traffic between East and West due to the [[Uprising of 1953 in East Germany]].

From 4 October 1953, all S-Bahn trains crossing the border between East Germany and Berlin had to pass a border checkpoint in East Germany. Travellers from East Germany were checked before entering any part of Berlin, to identify individuals intending to escape into West Berlin or smuggling rationed or rare goods into West Berlin. S-Bahn trains were checked at [[Hoppegarten]], [[Mahlow]], and [[Zepernick station|Zepernick]] in East Germany bordering East Berlin and in [[Hohen Neuendorf]], Potsdam-Griebnitzsee, and [[Staaken]]-Albrechtshof in East Germany bordering West Berlin. On 4 June 1954, the ''Bahnhof Hennigsdorf Süd'' station located next to West Berlin was opened solely for border controls, also to monitor West Berliners entering or leaving East Berlin, which they could still do freely, while they were not allowed to cross into East Germany proper without a special permit.

In 1951, the Reichsbahn began construction work on the [[Berlin outer ring|Berlin outer-circle railway line]]. This circular line connected all train routes heading for West Berlin and accommodated all domestic GDR traffic, thus directing railway traffic into East Berlin while by-passing West Berlin. Commuters in the East German suburbs around West Berlin now boarded ''Sputnik'' express trains, which took them into East Berlin without crossing any western sectors. With the completion of the outer-circle railway, there was no further need for express S-Bahn trains crossing the West Berlin border and thus their service ended on 4 May 1958, while stopping S-Bahn trains continued service. However, while East Germans could get off in West Berlin, West Berliners needed the hard-to get permits to enter East Germany by S-Bahn. With the construction of the Berlin Wall on 13 August 1961, all remaining railway traffic between West Berlin and its East German suburbs ended. Rail traffic between East and West Berlin was sharply reduced and restricted to a small number of checkpoints under GDR control. East Berliners and East Germans were then unable to freely enter and leave West Berlin. However, international visitors could obtain visas for East Berlin upon crossing one of the checkpoints at the Wall.{{citation needed|reason=|date=August 2015}}

Following the [[Détente|policy of détente]] of the ''Federal Government'' under Chancellor [[Willy Brandt]], West Berliners could again apply for visas to visit East Germany, which were granted more freely than in the period until 1961. On 4 June 1972, West Berlin's public transport operator ''BVG'' could open its first bus line into the East German suburbs since 1950 (line E to Potsdam via ''Checkpoint Bravo'' as it was known to the US military). This route was open only to persons bearing all the necessary East German permits and visas. For visits to East Germany, West Berliners could use four checkpoints along the East German border around West Berlin: The two road transit checkpoints Dreilinden (W)/Drewitz (E) and Berlin-[[Heiligensee]] (W)/Stolpe (E) as well as the old transit checkpoint at Heerstraße (W)/Staaken (E) and the checkpoint at Waltersdorfer Chaussee (W)/[[Schönefeld, Brandenburg|Schönefeld]] (E), which was also open for travellers boarding international flights at [[Berlin Schönefeld Airport|Schönefeld Airport]].{{citation needed|reason=|date=August 2015}}

===Traffic between East and West Berlin===
While East and West Berlin became formally separate jurisdictions in September 1948, and while there were travel restrictions in all other directions for more than a decade, freedom of movement existed between the western sectors and the eastern sector of the city. However, time and again Soviet and later East German authorities imposed temporary restrictions for certain persons, certain routes, and certain means of transport. Gradually the eastern authorities disconnected and separated the two parts of the city.<ref>{{Cite web |date=2025-03-20 |title=Berlin Wall {{!}} Definition, Length, & Facts {{!}} Britannica |url=https://www.britannica.com/topic/Berlin-Wall |access-date=2025-03-27 |website=www.britannica.com |language=en}}</ref>

While the Soviets blocked all transport to West Berlin (Berlin Blockade between 24 June 1948 to 12 May 1949), they increased food supplies in East Berlin in order to gain the compliance of West Berliners who at that time still had free access to East Berlin. West Berliners buying food in East Berlin were regarded as approving of the Soviet attempt to get rid of the Western Allies in West Berlin. This was seen as support by the communists and as treason by most Westerners. Until that time all over Germany food and other necessary supplies had been available only with ration stamps issued by one's municipality. This was the case in East Berlin until the [[Berlin Blockade#The Communist putsch in the municipal government|Communist putsch in Berlin's city government]] in September 1948 – the unitary City Council of [[Greater Berlin]] ({{langx|de|link=no|Magistrat von Groß Berlin}}) for East and West.{{citation needed|reason=|date=August 2015}}

By July 1948 a mere 19,000 West Berliners out of a total of almost 2&nbsp;million covered their food requirements in East Berlin. Thus, 99% of West Berliners preferred to live on shorter supplies than before the Blockade, to show support for the Western Allies' position. In West Germany rationing of most products ended with the introduction of the Western Deutsche Mark on 21 June 1948. The new currency was also introduced in West Berlin on 24 June and this, at least officially, was the justification for the Soviet Blockade due to which rationing in West Berlin had to continue. However, in the course of the [[Berlin Air Lift]] some supplies were increased beyond the pre-Blockade level and therefore rationing of certain goods in West Berlin was stopped.<ref>{{Cite book |last=Schrader |first=Helena |url=https://www.worldcat.org/oclc/771875699 |title=The Blockade Breakers: The Berlin Airlift |date=2011 |publisher=History Press |isbn=978-0-7524-6803-7 |location=Stroud |pages=235 |oclc=771875699}}</ref>

While West Berliners were officially welcome to buy food in East Berlin, the Soviets tried to prevent them from buying other essential supplies, particularly coal and other fuel. For this reason, on 9 November 1948, they opened checkpoints on 70 streets entering West Berlin and closed the others for horse carriages, lorries and cars, later (16 March 1949) the Soviets erected roadblocks on the closed streets. From 15 November 1948, West Berlin ration stamps were no longer accepted in East Berlin.{{citation needed|date=December 2023}} All the same, the Soviets started a campaign with the slogan ''The smart West Berliner buys at the [[Handelsorganisation|HO]]'' ({{langx|de|link=no|Der kluge West-Berliner kauft in der HO}}), the HO being the Soviet zone chain of shops. They also opened so-called "Free Shops" in the Eastern Sector, offering supplies without ration stamps, but denominated at extremely high prices in Eastern [[East German Mark|Deutsche Marks]]. Ordinary East and West Berliners could only afford to buy there if they had income in Western Deutsche Mark and bartered the needed Eastern Deutsche Mark on the spontaneous currency markets, which developed in the British sector at the Zoo station.{{citation needed|date=December 2023}} Their demand and supply determined a barter ratio in favour of the Western Deutsche Mark with more than 2 Eastern Deutsche Marks offered for one Western Deutsche Mark. After the Blockade, when holders of Western Deutsche Marks could buy as much they could afford, up to five and six east marks were offered for one west mark. In the East, however, the Soviets had arbitrarily decreed a rate of 1 for 1 and exchanging at other rates was criminalised.

On 12 May 1949, the Blockade ended and all roadblocks and checkpoints between East and West Berlin were removed. The Berlin Airlift, however, continued until 30 September 1949 in order to build up supplies in West Berlin (the so-called [[Senate Reserve]]), in readiness for another possible blockade, thus ensuring that an airlift could then be restarted with ease. On 2 May 1949, power stations in East Berlin started again to supply West Berlin with sufficient electricity. Before then, electrical supply had been reduced to just a few hours a day after the normal supplies had been interrupted at the start of the Blockade.{{citation needed|date=December 2023}} However, the Western Allies and the West Berlin City Council decided to be self-sufficient in terms of electricity generation capacity, to be independent of Eastern supplies and not to be held to ransom by the eastern authorities. On 1 December 1949 the new ''power station West'' ({{langx|de|link=no|Kraftwerk West}}, in 1953 renamed after the former Governing Mayor of West Berlin into {{lang|de|Kraftwerk [[Ernst Reuter|Reuter]] West}}) went online and West Berlin's electricity board declared independence from Eastern supplies. However, for a time Eastern electricity continued to be supplied albeit intermittently. Supply was interrupted from 1 July until the end of 1950 and then started again until 4 March 1952, when the East finally switched it off. From then on West Berlin turned into an 'electricity island' within a pan-European electricity grid that had developed from the 1920s, because electricity transfers between East and West Germany never fully ceased.{{citation needed|date=December 2023}}

In 1952, West Berliners were restricted entry to East Germany proper by means of a hard-to-obtain East German permit. Free entry to East Berlin remained possible until 1961 and the building of the Wall. [[Berlin U-Bahn|Berlin's underground]] ({{lang|de|Untergrundbahn, U-Bahn}}) and [[Berlin S-Bahn|Berlin's S-Bahn]] (a metropolitan public transit network), rebuilt after the war, continued to span all occupation sectors. Many people lived in one half of the city and had family, friends, and jobs in the other. However, the East continuously reduced the means of public transport between East and West, with private cars being a very rare privilege in the East and still a luxury in the West.{{citation needed|date=December 2023}}

Starting on 15 January 1953 the tram network was interrupted. East Berlin's public transport operator {{lang|de|Berliner Verkehrsbetriebe}} (''BVG''-East, ''BVB'' as of 1 January 1969) staffed all trams, whose lines crossed the sectorial border, with women drivers, who were not permitted as drivers by the ''BVG'' (West), West Berlin's public transport operator. Instead of changing the Western rules, so that the Easterly intended interruption of the cross-border tram traffic would not happen, the ''BVG'' (West) insisted on male drivers. Cross-border tram traffic ended on 16 January.<ref>It took the ''BVG'' (West) until 1 November 1973 to employ the first female bus driver, by which time all tram lines had been closed down in West Berlin.</ref> In East German propaganda this was a point for the East, arguing that the West did not allow drivers coming with their trams from the East to continue along their line into the West, but remaining silent on the fact that the end of cross-border tram traffic was most welcome to the East. The underground and the S-Bahn networks, except the above-mentioned ''traverse S-Bahn trains'', continued to provide services between East and West Berlin. However, occasionally the East Berlin police – in the streets and on cross-border trains in East Berlin – identified suspicious behaviour (such as carrying heavy loads westwards) and watched out for unwelcome Westerners.{{citation needed|date=December 2023}}

Occasionally, West Germans were banned from entering East Berlin. This was the case between 29 August and 1 September 1960, when ex-prisoners of war and deportees, ''homecomers'' ({{langx|de|link=no|Heimkehrer}}), from all around West Germany and West Berlin met for a convention in that city. The ''homecomers'' released mostly from a long detention in the Soviet Union were unwelcome in East Berlin.<ref>''Homecomers'' were either German civilians who had been deported into the Soviet Union from those territories it conquered, or former [[Wehrmacht]] soldiers and [[SS]] fighters, whom the Soviet Union kept as prisoners of war. They worked for many years as forced labourers in the Soviet Union, before they were finally released.</ref> As they could not be recognised through their identification papers, all West Germans were banned from East Berlin during those days. West Berliners were allowed, since the quadripartite Allied status quo provided for their free movement around all four sectors. From 8 September 1960 on, the East subjected all West Germans to apply for a permit before entering East Berlin.<ref>{{cite book |last1=Major |first1=Patrick |title=Behind the Berlin Wall |date=2010 |publisher=Oxford University Press |location=New York, New York |isbn=978-0-19-924328-0 |page=47 |url=https://books.google.com/books?id=9v5mUPulP58C |access-date=18 June 2020 |archive-date=2 June 2022 |archive-url=https://web.archive.org/web/20220602060240/https://books.google.com/books?id=9v5mUPulP58C |url-status=live }}</ref><ref>{{cite book |title=Germany and Eastern Europe Since 1945 From the Potsdam Agreement to Chancellor Brandt's "Ostpolitik" |date=1973 |publisher=Scribner |location=Bonn |isbn=9780684131900 |page=168 |url=https://books.google.com/books?id=9cqvokVM_NQC |access-date=10 August 2021 |archive-date=2 June 2022 |archive-url=https://web.archive.org/web/20220602060326/https://www.google.com/books/edition/Germany_and_Eastern_Europe_Since_1945/9cqvokVM_NQC?hl=en&gbpv=0 |url-status=live }}</ref>

As the communist government in the East gained tighter control, and the economic recovery in the West significantly outperformed the East, more than a hundred thousand East Germans and East Berliners left East Germany and East Berlin for the West every year. East Germany closed the borders between East and West Germany and sealed off the border with West Berlin in 1952; but because of the quadripartite Allied status of the city, the {{cvt|46|km|mi|adj=on}}-long sectorial border between East and West Berlin remained open.

To stop this drain of people defecting, the East German government built the Berlin Wall, thus physically closing off West Berlin from East Berlin and East Germany, on 13 August 1961. All Eastern streets, bridges, paths, windows, doors, gates, and sewers opening to West Berlin were systematically sealed off by walls, concrete barriers, barbed wire, and/or bars. The Wall was directed against the Easterners, who by its construction were no longer allowed to leave the East, except with an Eastern permit, not usually granted.
Westerners were still granted visas on entering East Berlin. Initially eight street checkpoints were opened, and one checkpoint in the [[Berlin Friedrichstraße railway station]], which was reached by one line of the Western underground (today's [[U6 (Berlin U-Bahn)|U 6]]), two Western S-Bahn lines, one under and one above ground (approximately today's [[S2 (Berlin)|S 2]] and [[S3 (Berlin)|S 3]], however, lines changed significantly from 1990 onwards), and ''transit trains'' between West Germany and West Berlin started and ended there.
[[File:Karte berliner mauer en.jpg|thumb|Map showing location of the Berlin Wall and transit points]]
The eight street checkpoints were – from North to South along the Wall – on Bornholmer Straße, Chausseestraße, Invalidenstraße, [[Berlin Friedrichstraße station]], [[Friedrichstraße]] ([[Checkpoint Charlie]] in US military denomination, since this crossing was to their sector), Heinrich-Heine-Straße, [[Oberbaum Bridge|Oberbaumbrücke]], and [[Sonnenallee, Berlin|Sonnenallee]].<ref>{{cite web |title=Border crossings between East and West Berlin |url=http://www.berlin.de/mauer/en/sites/former-checkpoints/ |website=Berlin.de |date=2 May 2016 |access-date=3 February 2017 |archive-date=4 February 2017 |archive-url=https://web.archive.org/web/20170204085740/http://www.berlin.de/mauer/en/sites/former-checkpoints/ |url-status=live }}</ref>
[[File:Bundesarchiv Bild 173-1282, Berlin, Brandenburger Tor, Wasserwerfer.jpg|thumb|right|An eastern water cannon vehicle directed at western protesters in front of the [[Brandenburg Gate]], August 1961]]

When the construction of the Wall started after midnight early on 13 August, West Berlin's Governing Mayor Willy Brandt was on a West German federal election campaigning tour in West Germany. Arriving by train in [[Hanover]] at {{nobr|4 am}} he was informed about the Wall and flew to West Berlin's [[Tempelhof Central Airport]].

Over the course of the day he protested along with many other West Berliners on [[Potsdamer Platz]] and at the Brandenburg Gate. On 14 August, under the pretext that Western demonstrations necessitated it, the East closed the checkpoint at the Brandenburg Gate 'until further notice', a situation that was to last until 22 December 1989, when it was finally reopened.

On 26 August 1961, East Germany generally banned West Berliners from entering the Eastern sector. West Germans and other nationals, however, could still get visas on entering East Berlin. Since intra-city phone lines had been cut by the East already in May 1952 (see below) the only remaining way of communication with family or friends on the other side was by mail or at meeting in a motorway restaurant on a ''transit route'', because the ''transit traffic'' remained unaffected throughout.{{citation needed|reason=|date=August 2015}}

On 18 May 1962 East Germany opened the so-called [[Tränenpalast]] checkpoint hall (''Palace of Tears'') at Berlin Friedrichstraße station, where Easterners had to say a sometimes tearful farewell to returning Westerners as well as the few Easterners who had managed to get a permit to visit the West. Until June 1963 the East deepened its border zone around West Berlin in East Germany and East Berlin by clearing existing buildings and vegetation to create an open field of view, sealed off by the Berlin Wall towards the West and a second wall or fence of similar characteristics to the East, observed by armed men in towers, [[Schießbefehl|with orders to shoot at escapees]].{{citation needed|reason=|date=August 2015}}
[[File:Bundesarchiv B 145 Bild-P086547, Berlin, Sektorenübergang Oberbaumbrücke.jpg|thumb|upright|Western police awaiting an eastern border controller at the opening of a new pedestrian border crossing. View into the vaults of [[Oberbaumbrücke]], 21 December 1963.]]

Finally, in 1963, West Berliners were again allowed to visit East Berlin. On this occasion a further checkpoint for pedestrians only was opened on the [[Oberbaumbrücke]]. West Berliners were granted visas for a one-day visit between 17 December 1963 and 5 January the following year. 1.2&nbsp;million out of a total 1.9&nbsp;million West Berliners visited East Berlin during this period. In 1964, 1965, and 1966 East Berlin was opened again to West Berliners, but each time only for a limited period.

East Germany assigned different legal statuses to East Germans, East Berliners, West Germans, and West Berliners, as well as citizens from other countries in the world. Until 1990 East Germany designated each [[Berlin border crossings#Border crossings|Border crossings in East Berlin]] for certain categories of persons, with only one street checkpoint being open simultaneously for West Berliners and West Germans (Bornholmer Straße) and ''Berlin Friedrichstraße railway station'' being open for all travellers.{{citation needed|reason=|date=August 2015}}

On 9 September 1964, the East German [[Government of East Germany|Council of Ministers]] (government) decided to allow Eastern pensioners to visit family in West Germany or West Berlin. According to the specified regulations valid from 2 November on Eastern pensioners could apply and were usually allowed, to travel into the West to visit relatives once a year for a maximum of four weeks. If pensioners decided not to return, the government did not miss them as manpower, unlike younger Easterners, who were subject to a system of labour and employment, which demanded that almost everybody work in the Eastern command production system.

On 2 December 1964 East Germany, always short of hard currency, decreed that every Western visitor had to buy a minimum of 5 Eastern ''Mark der Deutschen Notenbank'' per day (MDN,<ref>Literally in ''Mark of the German Bank of Issue'', which was then the name of the East German state bank.</ref> 1964–1968 the official name of the East German mark, to distinguish it from the West Deutsche Mark) at the still held arbitrary compulsory rate of 1:1. The 5 marks had to be spent, as exporting Eastern currency was illegal, which is why importing it after having bargained for it at the currency market at Zoo station was also illegal. Western pensioners and children were spared from the compulsory exchange (officially in {{langx|de|[[:de:Mindestumtausch|Mindestumtausch]]}}, i.e. ''minimum exchange''). Not long after East Germany held the first cash harvest from the new compulsory exchange rules by allowing West Berliners to visit East Berlin once more for a day during the Christmas season. The following year, 1965, East Germany opened the travelling season for West Berliners on 18 December. In 1966 it opened for a second harvest of Western money between the Easter (10 April) and [[Pentecost]] (29 May) holidays and later again at Christmas.{{citation needed|reason=|date=August 2015}}

The situation only changed fundamentally after 11 December 1971 when, representing the two German states, [[Egon Bahr]] from the West and Michael Kohl from the East signed the [[Transit Agreement (1972)|Transit Agreement]]. This was followed by a similar agreement for West Berliners, once more allowing regular visits to East Germany and East Berlin.{{citation needed|reason=|date=August 2015}}

After ratification of the Agreement and specifying the relevant regulations, West Berliners could apply for the first time again for visas for any chosen date to East Berlin or East Germany from 3 October 1972 onwards. If granted, a one-day-visa entitled West Berliners to travel to the East until 2&nbsp;am the following day. The visitors were now spared the visa fee of 5 Western Deutsche Marks, not to be confused with the compulsory exchange amounting to the same sum, but yielding in return 5 Eastern marks. This financial relief did not last long, because on 15 November 1973 East Germany doubled the compulsory exchange to 10 Eastern marks, payable in West German Deutsche Marks at par.{{citation needed|reason=|date=August 2015}}
[[File:Bundesarchiv Bild 183-B1228-0010-003, Berlin, West-Berliner Besucher in Ostberlin.jpg|thumb|left|West Berliners entering East Berlin at the border crossing Chausseestraße on 28 December 1963 after having been banned from visiting the eastern sector for more than two years]]

One-day visas for East Berlin were now issued in a quickened procedure; visas for longer stays and visas for East Germany proper needed a prior application, which could be a lengthy procedure. To facilitate applications for West Berliners seeking such Eastern visas, the GDR Foreign Ministry was later allowed to open ''Offices for the Affairs of Visits and Travelling'' ({{langx|de|link=no|Büros für Besuchs- und Reiseangelegenheiten}}) in West Berlin, which were not allowed to show any official symbols of East Germany. The Eastern officials working commuted every morning and evening between East and West Berlin. Their uniforms showed no official symbols except the name {{lang|de|Büro für Besuchs- und Reiseangelegenheiten}}. They accepted visa applications and handed out confirmed visas issued in the East to the West Berlin applicants. A shed formerly housing one such {{lang|de|Büro für Besuchs- und Reiseangelegenheiten}} can be found on Waterlooufer 5–7 in Berlin-[[Kreuzberg]], close to [[Hallesches Tor (Berlin U-Bahn)|Hallesches Tor underground station]].<ref>''Wissenswertes über Berlin: Nachschlagewerk für zuziehende Arbeitnehmer von A-Z'' (<sup>1</sup>1968), Senator für Wirtschaft und Arbeit (ed.), Berlin (West): Senator für Wirtschaft und Arbeit, <sup>12</sup>1986, p. 117. No ISBN.</ref>

Another form of traffic between East and West Berlin was the transfer of West Berlin's sewage into East Berlin and East Germany through the sewer pipes built in the late 19th and early 20th centuries. The sewage flowed into the East because most of the pre-war sewage treatment facilities, mostly [[sewage farm]]s, happened to be in the East after the division of the city. Sewer pipes, however, once discovered as a way to flee the East, were blocked by bars. West Berlin paid for the treatment of its sewage in Western Deutsche Marks which were desperately needed by the East German government. Since the methods used in the East did not meet Western standards, West Berlin increased the capacity of modern sewage treatment within its own territory, such that the amount of its sewage treated in the East had been considerably reduced by the time the Wall came down.

The situation with refuse was similar. The removal, burning or disposal of the ever-growing amount of West Berlin's rubbish became a costly problem, but here too an agreement was found since West Berlin would pay in Western Deutsche Marks. On 11 December 1974 East Germany and West Berlin's garbage utility company ''BSR'' signed a contract to dispose of refuse on a dump right beside the Wall in East German Groß-Ziethen (today a part of [[Schönefeld, Brandenburg|Schönefeld]]). An extra checkpoint, solely open for Western bin lorries (garbage trucks), was opened there. Later on, a second dump, further away, was opened in Vorketzin, a part of [[Ketzin]].{{citation needed|reason=|date=August 2015}}

As for the S-Bahn, operated throughout Berlin by the East German Reichsbahn, the construction of the Wall meant a serious disruption of its integrated network, especially of the [[Berlin Ringbahn|Berlin's circular S-Bahn line]] around all of the Western and Eastern inner city. The lines were separated and those mostly located in West Berlin were continued, but only accessible from West Berlin with all access in East Berlin closed. However, even before the Wall had been built, West Berliners increasingly refrained from using the S-Bahn, since boycotts against it were issued, the argument being that every S-Bahn ticket bought provided the GDR government with valuable Western Deutsche Marks.{{citation needed|reason=|date=August 2015}}
[[File:Bundesarchiv Bild 183-1989-1118-018, Berlin, Grenzübergang Bornholmer Straße.jpg|thumb|right|East Berliners, just having passed the now-open eastern checkpoint Bornholmer Straße, passing Bösebrücke into the French sector of Berlin on 18 November 1989]]

Usage dropped further as the Western public transport operator ''BVG'' (West) offered parallel bus lines and expanded its network of underground lines. After the construction of the Wall, ridership fell so much that running the S-Bahn lines in West Berlin turned into a loss-making exercise: wages and maintenance – however badly it was carried out – cost more than income from ticket sales. Finally, the Reichsbahn agreed to surrender operation of the S-Bahn in West Berlin, as had been determined by all Allies in 1945, and on 29 December 1983 the Allies, the Senate of Berlin (West; i.e. the city state government) and the Reichsbahn signed an agreement to change the operator from Reichsbahn to ''BVG'' (West) which took effect on 9 January 1984.<ref>{{Cite journal |last=Fabian |first=Thomas |date=2000 |title=The evolution of the Berlin urban railway network. |journal=Japan Railway and Transport Review |volume=25 |pages=22–23}}</ref>

On 9 November 1989 East Germany opened the borders for East Germans and East Berliners, who could then freely enter West Berlin. West Berlin itself had never restricted their entry. For West Berliners and West Germans the opening of the border for free entry lasted longer. The regulation concerning one-day-visas on entering the East and the compulsory minimum exchange of 25 Western Deutsche Marks by 1989, continued. However, more checkpoints were opened. Finally, on 22 December 1989, East Germany granted West Berliners and West Germans free entry without charge at the existing checkpoints, demanding only valid papers. Eastern controls were slowly eased into spot checks and finally abolished on 30 June 1990, the day East and West introduced the ''union concerning currency, economy and social security'' ({{langx|de|[[:de:Währungs-, Wirtschafts- und Sozialunion|Währungs-, Wirtschafts- und Sozialunion]]}}).{{citation needed|reason=|date=August 2015}}

===Traffic between different parts of West Berlin crossing the East===
When the Wall was built in 1961, three metro lines starting in northern parts of West Berlin passed through tunnels under the Eastern city centre and ended again in southern parts of West Berlin. The lines concerned were today's underground lines [[U6 (Berlin U-Bahn)|U 6]] and [[U8 (Berlin U-Bahn)|U 8]] and the S-Bahn line [[S2 (Berlin)|S 2]] (today partly also used by other lines). On the sealing off of West Berlin from East Berlin by the Berlin Wall the entrances of the stations on these lines located in East Berlin were shut. However, western trains were allowed to continue to pass through without stopping. Passengers of these trains experienced the empty and barely lit [[Ghost station#Ghost stations in Berlin|ghost stations]] where time had stood still since 13 August 1961. West Berlin's public transport operator ''BVG'' (West) paid the east an annual charge in Western Deutsche Marks for its underground lines to use the tunnels under East Berlin. [[U6 (Berlin U-Bahn)|U 6]] and [[S2 (Berlin)|S 2]] also had one subterranean stop at the Eastern [[Berlin Friedrichstraße railway station]], the only station beneath East Berlin where western U Bahn trains were still allowed to stop. Passengers could change there between U 6, S 2 and the elevated S 3 (then starting and ending in Friedrichstraße) or for the transit trains to West Germany, buy duty-free tobacco and liquor for Western marks in GDR-run [[Intershop]] kiosks, or enter East Berlin through a checkpoint right in the station.{{citation needed|reason=|date=August 2015}}