to enable this commenced in April 2010, and was originally expected to be completed by 2017. Construction works suffered from continued difficulties, mainly concerning high water contents in the soil; in November 2015 the opening date was postponed, with the link finally opening on 4 December 2020. The link is in length, connecting the former U55 terminus at Brandenburger Tor with the rest of the U5 at Alexanderplatz. The link features three new U-Bahn stations at Rotes Rathaus, Museumsinsel and Unter den Linden. Unter Den Linden provides an interchange with line U6, replacing the former U6 station at Französische Straße, located a little further to the south on Friedrichstraße, which closed on 3 December 2020. End of operations Operations on the line ceased on March 17, 2020, until its incorporation into the new U5 line on December 4 of that year. This took place earlier than originally planned due to much lower ridership as a result of the COVID-19 crisis. Reopened as U5 Line The three stations reopened as a part of U5 Line Eastern extension on 4 December 2020. References External links Projekt U5 pics from U55 Berlin U-Bahn lines Railway lines opened in 2009 Railway lines closed in 2020 2009 establishments in Germany 2020 disestablishments in Germany