BER has hardly been completed when another major project goes into operation in Berlin. It was also demanding, but caused less trouble. The line of the "Kanzler-U-Bahn" is now complete.

"We will open this line on 4 December 2020, the day of St. Barbara, the patron saint of miners and tunnel builders," announced Rolf Erfurt, head of operations of the Berlin transport authority (BVG), as early as August. Next week the time has come, but in view of the ongoing corona pandemic there will be no local celebrations. Instead, the transport companies invite all interested people to experience the opening of the new U5 on 4 December from 11:40 am in the livestream on BVG.de.

The first regular trains will stop at the two new underground stations Unter den Linden and Rotes Rathaus at around 12 pm on Friday afternoon. After that, the regular timetable will apply along the entire length of the U5. On weekdays outside rush hour, trains will run every five minutes during the day, and every 4 2/3 minutes during rush hours. The third new underground station, Museum Island, will continue to operate without a stop until summer 2021. The extension and completion of the distribution level and accesses are still underway. The Französische Strasse U6 station will be closed. It is located close to the new Unter den Linden station, where the U6 and U5 lines cross.

The 2.2-kilometre-long route closes the gap in the U5 between the Brandenburger Tor and the Alexanderplatz. Passengers can then travel between the Hauptbahnhof and Hönow in the east of the city without changing trains.

Initially, commissioning was planned for 2017. However, the sandy, wet building ground in Berlin-Mitte had repeatedly caused difficulties. For several years, the Implenia company drove a 700-tonne tunnel boring machine with a 6.70-metre cutting wheel through the subsoil. Those responsible called it "Bärlinde". Herrenknecht's custom-built machine has long been dismantled.