History of the Berlin U-Bahn…
The construction of the Berlin U-Bahn occurred in three major phases:1. Up to 1913 – the construction of the Kleinprofil (small profile) network in Berlin, Charlottenburg, Schöneberg, and Wilmersdorf2. Up to 1930 – the introduction of the Großprofil (large profile) network that established the first North-South lines3. From 1953 on – further development after the Second World War
At the end of the 19th century, city planners in Berlin were looking for solutions to the increasing traffic problems facing the city. As potential solutions, industrialist and inventor Werner von Siemens suggested the construction of elevated railways, while AEG proposed an underground system. Berlin city administrators feared an underground would damage the sewers, favouring an elevated railway following the path of the former city walls; however, the neighbouring city of Charlottenburg did not share Berlin’s fears, and disliked the idea of an elevated railway running along Tauentzienstraße. Years of negotiations followed until, on 10 September 1896, work began on a mostly-elevated railway to run between Stralauer Tor and Zoologischer Garten, with a short spur to Potsdamer Platz. Known as the “Stammstrecke”, the route was inaugurated on 15 February 1902, to immediate popularity. Before the year ended, the railway had been extended: by 17 August, east to Warschauer Brücke (Warschauer Straße); and, by 14 December, west to Knie (Ernst-Reuter-Platz).
Charlottenburg extended the line further westwards: by 1906, it had reached the town hall at Wilhelmplatz (Richard-Wagner-Platz); by 1908, Reichskanzlerplatz (Theodor-Heuss-Platz); and, by 3 November 1912, Sportpark (Olympia-Stadion). In Berlin’s city centre, Potsdamer Platz was disconnected — to be replaced by Leipziger Platz (Potsdamer Platz) — to allow an extension to the spur. The line underneath Leipziger Straße to Spittelmarkt opened in 1908; it was extended to Alexanderplatz by July 1913, with the Wilhelmplatz – Alexanderplatz route swiftly become the most popular of the Berlin U-Bahn. Three-and-a-half weeks later, on 27 July 1913, the northern extension to the S-bahn station (Schönhauser Allee) on Nordring was also opened.
In a bid to secure its own improvement, Schöneberg also wanted a connection to Berlin. The elevated railway company did not believe such a line would be profitable, so the city took it upon itself to build the first local underground in Germany. Running as a subsurface railway from Hauptstraße, the 2.9 km (1.8 mi) line needed a second, underground station at its Nollendorfplatz terminus, since the established station there was part of the elevated railway. The line took two years to construct; it was opened on 1 December 1910.
Just a few months earlier, work began on a fourth line to link Wilmersdorf in the south-west to the growing Berlin U-Bahn. Originally planned as a line from Wittenbergplatz to Breitenbachplatz, Wilmersdorf paid for the line to reach as far as Thielplatz. As a concession to Charlottenburg for travelling through the city, the construction of a track from Wittenbergplatz, under the Kurfürstendamm, to Uhlandstraße was also agreed upon. Both lines were opened on 12 October 1913; these were the last to open before the outbreak of World War I — and the subsequent economic difficulties faced by Germany — that prevented any further additions to the Berlin U-Bahn for ten years.