maintenance of the carriage shed finally led to its closure due to dilapidation in 2014. The hall is heritage-listed. Modifications During the construction of line G, now U9, an interchange station was to be built at the intersection of the two lines. However, since there was no station at the Spichernstraße/ Bundesallee intersection on the U3—then line 2—the Spichernstraße station was built. The nearby Nürnberger Platz station was closed and completely gutted on 1 July 1959. The area of the former central platform was converted into a double-track siding, which is accessed from Spichernstraße. However, the distance of 1106 metres between the Wittenbergplatz and Spichernstraße stations was considered unacceptable for the City West area, so the new Augsburger Straße station was built. It was considered necessary to minimise the impact on the existing structure at both new small-profile stations, so both were built with side platforms. They were opened on 2 June 1959 (Spichernstraße) and 8 May 1961 (Augsburger Straße). The architecture is strongly based on Grenander's model. The buildings were designed in a functional style based on designs by the then subway architect Bruno Grimmek. Augsburger Straße station was decorated with red-brown tiles and Spichernstraße with light blue tiles. In 1981, a second entrance building was built at Thielplatz station, which also houses a substation. This shortened the way to the campus of the Free University of Berlin. Extension to Warschauer Straße On 7 May 2018. the U3 was "extended" eastwards on the existing line used by the U1 to the terminus at Warschauer Straße. In other words, the route that existed until 2004 as the then U1 line was restored. This facilitates the movement of students and others from there to the Free University and extended the denser service from Nollendorfplatz eastwards. The extension of the line was facilitated by the new four-car class IK18 sets becoming available in April 2018. Opening dates 12 October 1913: Wittenbergplatz – Thielplatz 24 October 1926: Wittenbergplatz – Nollendorfplatz (underground) 22 December 1929: Thielplatz – Krumme Lanke 2 June 1959: Spichernstraße station opened; simultaneous closure of Nürnberger Platz station 8 May 1961: Augsburger Straße station Extension In the south, there are plans to extend the U3 towards the Berlin Mexikoplatz station, running via Lindenthaler Allee. Even though this would only take 700 meters of new tracks, the budgetary constraints of the Berlin Senate hinders completion. Frequency Train run every 5 minutes on