An Ode To Berlin’s U-Bahn

Brian Melican explores the complexity of Berlin’s U-Bahn…

As hard as it may be for those who come into daily contact with BVG to believe, Germany is envied, in the wider world, for its efficiently-run and tightly-woven networks of public transport. Among mass-transit professionals, Berlin especially is considered to have an almost text-book urban rail infrastructure.

The city’s S-Bahn, for instance, offers a comparatively rare degree of completion in the shape of a periphery circular line criss-crossed by north-south and east-west connections—the sort of journey-time cutting infrastructure Paris spent much of the late-twentieth century acquiring and which London, in the form of the Overground and delayed Crossrail, is still struggling to get operational.

Yet when it comes to beautiful, rational rail simplicity, Berlin’s S-Bahn is not matched by its U-Bahn. Although it is German-speaking Europe’s largest metro and very much part of the fabric of the city, the Berlin U-Bahn has a very different and altogether more complicated history than its heavy-rail counterpart.

Where the S-Bahn was planned and built in a systematic manner, with most of its current network in place prior even to the First World War—and, importantly, far before the destruction of the Second World War and the difficulties of division—the U-Bahn was a later and much more piecemeal affair whose development was curtailed by the post-war borders. At a time when other German cities such as Munich and Frankfurt were receiving entire new underground networks, Berlin’s U-Bahn was subject to a prolonged period of bonsai-like pruning from whose constraints it is only now beginning to escape.

This makes for some frustrating gaps in underground coverage, primarily in the former East and especially in terms of connections between outlying areas once divided by the Wall. Where the pre-existing S-Bahn circular and cross-town lines were simply reactivated after unification, by 1989 whole U-Bahn lines had been built to not cross between east and west. Yet it is precisely this troubled history makes the U-Bahn a rich well of Berlin history—and one that is still very much a part of its present.

“Hoch- und Untergrundbahn” – The beginnings of the Berlin U-Bahn

Below the overground U2 line in Prenzlauer Berg. Image by Paul Sullivan

While the S-Bahn ring was built around the city on what was greenfield land in the 1870s and the cross-town Stadtbahn was already rumbling along its iconic brick arches by 1882, Berlin’s first metro line was not opened until 1902. It was, in contrast to the S-Bahn, an attempt to tackle increasing traffic congestion within the city centre rather than a way of transporting people through it.

Running from what is today Ersnt-Reuter-Platz and was back then called Knie (“Knee”) through to Warschauer Brücke (today Warschauer Straße), much of this first line was built overground: from Gleisdreieck to Warschauer Straße, the current U1 uses the same metal viaducts that carried this first line; west of Gleisdreieck, the original route went underground under Nollendorfplatz and Zoo – and is today served by the U2.

This is important because it sheds light on common question which both newcomers and natives in Germany often ask themselves in their idle hours: why is the U-Bahn – Untergrundbahn – called the U-Bahn when so much of it runs not just above, but indeed several storeys overground? In Hamburg, for instance, whose U-Bahn was also begun in the early twentieth-century, whole sections of the original line runs on viaducts, too.

The answer is that, both in Berlin and elsewhere, the term U-Bahn only became established in the 1930s, after tunnelling had become cheaper and more common. When work on the Berlin U-Bahn started, the company was actually called the Hoch- und Untergrundbahn, with cheaper elevated sections often preferred if enough space was available and there were no pressing aesthetic considerations speaking against them.

This elevation-level-agnostic approach to building held throughout the first phase of the expansion of Berlin’s metro, which ran through to 1913 and created a network broadly resembling a skewed X, with the crossing at Gleisdreieck. On the eve of the First World War, the two main lines connected Prenzlauer Berg in the north east with Dahlem in the south west and Westend with Friedrichshain in the east, with a spur south to Schöneberg. Fittingly enough, this original core is today numbered U1 to U4 (back then, the lines where denominated with letters).

Apart from this numerical aide mémoire and their frequent above-ground sections, the other surefire way of telling if you are riding pre-WW1 Berlin U-Bahn is to watch out for feelings of slight claustrophobia. That is because all of the pre-First-World-War network was built in what later came to be known as Kleinprofil, best translated as “small loading gauge”. This should not be confused with track gauge, which is the same across the network, but describes the dimensions of the cars: on the pre-1913 lines, tunnels assumed a maximum car width of 2.30m (7”6), while lines built later— Großprofil—allowed for 2.65m (8”6).

Height is broadly similar across the whole network, though, which gives the Kleinprofil units a distinctive “squeezed” look compared to the square form of their Großprofil successors. Moreover, thanks to their height, even the smaller units are not a patch on squat London underground trains when it comes to provoking panic in those affected by fear of confined spaces.

They do, however, share some width-related features with them; most notably seating arrangements, with rows usually facing each other across the cars as they’re too narrow for four-seat groups. This, along with the areas of the city they serve, gives the Kleinprofil units no small amount of their character: it would seem hard to imagine the raucousness of a late-night ride on the U1 without two rows of tipsy night-owls facing each other across the car; four-seat grouping is markedly less conducive to spontaneous eye-contact and random interactions.

“U-Bahn für Groß-Berlin” – The (Not-Quite-So) Roaring Twenties

Image by Paul Sullivan

Construction on the Großprofil network began in the years immediately following the First World War and mirrored, with some delay, the vicissitudes of the 1920s as the nascent Weimar Republic first struggled through fiscal austerity and hyperinflation before, after a brief boom which gave the decade their “Roaring” moniker, stumbling into the Great Depression. The scope of the U-Bahn was also expanded by the Groß-Berlin-Gesetz (Greater Berlin Act) which, in 1920, brought previously independent municipalities such as Charlottenburg, Wilmersdorf, and Schöneberg into a ‘Greater Berlin’, extending the city’s administrative districts into areas which had previously been part of surrounding rural counties such as Teltow and Osthavelland.

Prior to the amalgamation, the only part of the network outside of Berlin had been the Schöneberg branch (today’s U4). The expansion opened up a strong administrative opportunity and an equally strong imperative to tackle the city’s ever-increasing congestion with new, larger underground lines: a standard element in contemporaneous photos of Berlin’s streets are bus-jams, and so a metro that could seat more passengers—and actually ran underground, minimising space demands at street level—became the order of the day.

Of course, tunnelling was considerably more expensive than building elevated viaducts, and with the stop-start economy of the 1920s, little of the planned expansion was realised. But the goal of reaching the S-Bahn ring was indeed achieved at Tempelhof, Frankfurter Allee, Gesundbrunnen, and Innsbrucker Platz (the tie-up at Hermannstraße would have to wait until 1996, as today’s U8 only got as far as Leinestraße before the Second World War).

Yet what was built in the interwar years has proven to be both lastingly effective and aesthetic. Primarily, the focus of this phase was on north-south connections from Wedding and Tegel through to Tempelhof and Neukölln, and today still, its results form the core of U5-U8. Stations such as Hermannplatz embody the spirit of the time—and point towards its travails. The high-roofed U7 platform, whose large ceiling lights lend it a brightness belying its subterranean nature, is testament to the desire to create a spacious and modern railway.

With the city’s exchequer strapped for cash, however, the Karstadt concern paid for much of the station’s ornamental decoration, securing direct access from the already-iconic Hermannplatz department store building in return, and ensuring that the network’s first escalator was installed so that its well-to-do clientele would only shop, not walk, until they dropped.

Yet for the genuinely expensive engineering work behind the railway, only the state had pockets deep enough. In the northern districts of Berlin, another major German corporation, AEG, had actually started building its own underground railway southwards prior to the war, but found itself in financial difficulty following the conflict and was forced to pass on the tunnels it had constructed to the city for completion. The line finished by the city is today’s U8, which crosses the U7 at Hermannplatz, and whose construction also led to the remodelling of Alexanderplatz, another station with an air of 1920s Berlin about it.

“Tränenpalast und Geisterbahnhöfe” – An U-Bahn divided

U Bahn Hallesches Tor in Kreuzberg. Image by Paul Sullivan

Alexanderplatz is an interesting station from which to trace the turbulent history of Berlin’s U-Bahn through the destruction of the Second World War, and into the decades of division which followed. One of the last of the 1920s construction projects to be completed was a new line from Alexanderplatz eastwards to Friedrichsfelde, the longest-standing section of today’s U5.

Running more or less dead straight under what are today Karl-Marx-Allee and Frankfurter Allee, it would be all too easy to assume that the line was part of megalomaniac urban planning of either the Nazis or the early-GDR Stalinists, but it actually predates both. Nevertheless, this line was one of the few existent at the post-war division which later found itself entirely in one of the two Berlins, and the only one which was entirely in the East. Due to its entirely underground course, it also suffered the least damage from bombing and fighting.

For much of the rest of the network, the Second World War and the ensuring division had far more deleterious effects. In the air raids of 1943 to 1945, the above-ground viaducts of the Kleinprofil network sustained widespread damage; at the landmark Oberbaumbrücke, for instance, the Osthafen station near what is now the terminus of the U1, Warschauer Straße, was entirely destroyed and never reconstructed; meanwhile, below ground, desperate SS troops dynamited the north-south S-Bahn tunnel in 1945, flooding it from the Landwehrkanal; through a connecting tunnel at Friedrichstraße, water flowed into much of the central underground U-Bahn system, too.

Yet while much of the war damage was swiftly repaired, the division of Berlin would have long-lasting effects. In 1949, the underground was officially divided into an East and a West company; this was in contrast to the S-Bahn, which, somewhat oddly, remained run from the East throughout the division and was thus studiously avoided by West Berliners not keen on financing the surrounding dictatorship (“Wer S-Bahn fährt, zahlt Ulbrichts Stacheldraht”; “If you ride the S-Bahn, you pay for Ulbricht’s barbed wire”).

In the uneasy years between the founding of the two German states and the erection of the Berlin Wall in 1961, many lines’ schedules changed, with trains from the West ending at the last station before the Soviet sector or the first one inside it; the West U-Bahn also inserted extra points at its ‘frontier stations’ so that trains could, if necessary, terminate there and pass back onto the down track to return. When the Wall went up overnight in August 1961, the usefulness of these modifications was immediately proved.

Seen from Alexanderplatz, what is now the U2 (then “Linie A”) suddenly ended at Mohrenstraße—Thälmannplatz during the Communist years; Wilhelmplatz before that, and soon to be changed to Anton-Wilhelm-Amo-Straße—while the West used a passing loop installed at Gleisdreieck to terminate its trains there. This left Potsdamer Platz unused and, urban mass transit systems abhorring a vacuum, the East U-Bahn was soon using it as an overnight depot for their Line A services despite the fact that it was in—or rather under—West Berlin. Yet while Line A was cut in two, Lines C and D, today’s U6 and U8, suffered a more sinister fate: as they started and ended in the Allied sectors and merely traversed the East, they were left to run as before – but with their stations in the GDR boarded up.

These Geisterbahnhöfe (ghost stations) became a particularly chilling symbol of the inhuman division of the city. The U8, for instance, left the West between Moritzplatz and Heinrich-Heine-Straße, only re-emerging before Voltastraße after passing, at reduced speed, through six barricaded phantom stops. At Alexanderplatz, those on the GDR side changing between today’s U2 and U5 would walk right past the entrances to the U8 platforms, which had been walled shut and disguised with specially copied tiles to the point that only seasoned commuters from the pre-Wall-years knew where they were.

Until the newer northern extension of the U8 was opened in the late-1970s, its near-amputated two-stop section between Voltastraße and Gesundbrunnen was all but deserted. And even once the additional stations out towards Wittenau brought some purpose—and some traffic—back to the northern part of the line, many riders heading south still preferred to change at Osloer Straße onto what is now the U9 and then again at Berliner Straße onto the U7 in order to avoid the disconcerting experience of passing through the Geisterbahnhöfe at walking speed.

Indeed, the U7 and U9 essentially trace the crescent of West Berlin around the East. While the core section of the U7 between Mehringdamm and Grenzallee had been built as part of the 1920s expansion, its extensions out to Rudow and Rathaus Spandau, as well of those of the today’s U6 out to Alt-Mariendorf and Alt-Tegel, were about improving transport links within West Berlin while minimising transit through the East and/or reliance on the S-Bahn; the U9 was a wholly western line that offered connections to all other lines except today’s U4.

Children of their time, these sections of pure-bred West-Berlin U-Bahn are today revered and reviled in equal measure thanks to 60s-70s station designs for which the most common cinematic comparisons are, depending on the level of flattery intended, 2001: Space Odyssey and A Clockwork Orange.

“Aus Kanzler-U-Bahn wird U5” – An U-Bahn reunited

Train on the U2 line. Image by Paul Sullivan

In terms of fictional references, the effect of the seedy trickery at Alexanderplatz was far closer to 1984, redolent of a regime for which no manipulation was too crude in the drive to shape its populace’s thoughts and emotions. Yet blocked entrances can easily be unblocked—and ghost stations easily revivified. Within days of the Fall of the Wall, Jannowitzbrücke just south of Alexanderplatz became the first of the phantoms to return to life, complete with handwritten signage and a hurriedly-installed passport control point to get it up and running in the ensuing limbo. The U8 was soon calling at Alexanderplatz again, too, and within a year, almost all of the U-Bahn network was once again operational in time for Reunification.

What has taken longer is for the network to outgrow the four decades of constraints placed on it. In view of the division, pre-War plans for an extension of the Line E (now U5) west from Alexanderplatz had been dropped by both Berlin authorities, for instance, and in East Berlin, attention refocussed in the other direction: the U5’s extensions out to Hönow were the only part of the U-Bahn network built under the GDR, whose section of Berlin was smaller and happened to have far more S-Bahn than U-Bahn lines. Almost immediately after Reunification, a new East-West U-Bahn connection was identified as a priority, all the more so after the location of Berlin’s new Hauptbahnhof was settled and its lack of an U-Bahn connection noted as one of its few severe drawbacks. Work began in 1995.

Yet after decades of division, in the 1990s, Berlin was faced with a new overarching issue: impecunity. These were the years of “arm, aber sexy”, of mass sell-offs of housing stock and other family silver in desperate attempts to plug holes in a municipal budget ravaged by the withdrawal of subsidies from the former West. In 2002, work on the U5 was halted and only the partially-completed section between Hauptbahnhof and Brandenburger Tor was finished, opening in 2009 as the embarrassing mile-long shuttle-service U55 used, if at all, by MPs returning from their constituencies and heading directly to parliamentary debates and the odd confused tourist.

It was only after three years of dysfunctional service—since the almost two-kilometre stretch was isolated from the rest of the network, trains had to be winched up and transported by road to the depot for servicing; drivers dreaded the repetitive monotony of a day-long shift on the five-minute, three-stop line – that Berlin’s Senate authorised completion of the rest of the line, which finally opened in 2020 to an unfortunately underwhelming reception due to the Pandemic as well as the extension’s ‘luxuriously bland’ aesthetics.

This leaves Berlin’s Hauptbahnhof connected to the U-Bahn, but only in one direction; a planned extension westwards out towards Turmstraße is now on ice as the Senate eyes up a cheaper tram line. This is unique in German urban transit, where central stations are also usually at the centre of metro lines rather than at their peripheries, and is, perhaps, a fitting provisional end-point for Berlin’s U-Bahn as a transport network which has always reflected the city as it is rather than the city as it wants to be: a city with sporadic financial resources; a city with a messy past and a (marginally less) messy present; a city which is always—in some endearing and infuriating way—incomplete.

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