U3 is a line on the Berlin U-Bahn created in its current version on 7 May 2018. The routing is largely the same as the previous U2 until 1993, but it runs from Krumme Lanke to Wittenbergplatz. The route was renumbered to U1 from 1993 to 2004. It was extended one station further east to Nollendorfplatz to enable trains to be reversed and to allow one-stop transfer to the U4 in 2003. On 7 May 2018, the U3 was extended to run with the U1 all the way to Warschauer Straße. Changing routes and designations The line to Krumme Lanke station has changed several times in the course of its existence. Initially, line A connected Krumme Lanke in the southwest of Berlin with Pankow in the north and was marked in red on the network maps. From 1957 two lines served the southwestern section of the line: the red route AII to Pankow as before, and a green route BII to Warschauer Brücke. After the construction of the Berlin Wall in 1961, the small profile network was completely redesigned in 1966. The route to Dahlem received the line designation 2, running initially to Gleisdreieck via Bülowstraße, and from 1972 only to Wittenbergplatz. Line 3—with a dark green colour code—was assigned to the Uhlandstraße–Wittenbergplatz stub track. This changed again in 1993 as the line was marked green again and received the line number U1, which ran to Warschauer Straße. The designation U3 for the route to Uhlandstraße, however, disappeared, as this was now served by line U15, also running to Warschauer Straße. Finally, the line was redesignated from the network timetable change in December 2004 to the turquoise U3. Since 2005, the line has also operated as a late night service. From 4 to 7 March 2013, the trains were designated again as U1 between Krumme Lanke and Warschauer Straße due to construction work on the section between Uhlandstraße and Kurfürstendamm. Unlike in analogous cases (U12), no corresponding line designation (U13) was introduced here. From 2004 to 2018, line U3 was limited to the Krumme Lanke–Nollendorfplatz section. Current route The U3 currently starts at Warschauer Straße. From there it runs together with the U1 on its line to Wittenbergplatz. Under Tauentzienstraße it turns in a tight right-angle curve to the southwest and follows the streets of Nürnberger Straße and Spichernstraße to Spichernstraße station (interchange station to the U9) at the intersection