Berlin opens long-awaited 1.4-mile subway extension

A long-awaited subway extension that tunnels under one of Berlin's best-known boulevards and improves transport links from the German capital's central railway station opened Friday.

The 2.2-kilometer (1.4-mile) new section of the U5 line runs from its previous terminus at the Alexanderplatz, once communist East Berlin's central square, to the Brandenburg Gate. There, it joins up with a short subway section opened in 2009 that runs to the central station; until now, the line had little practical use and was used sparsely and mainly by tourists.

The new section tunnels under the Unter den Linden boulevard, where construction work has helped snarl traffic in recent years. There are three new stations, including stops at city hall and next to Berlin's Museum Island complex, although the latter isn't expected to open until next summer.

The opening of the subway extension was originally planned for 2017, but Berlin's sandy soil complicated construction. Officials have put the cost at up to 540 million euros ($655 million).

Plans to extend the U5, which connects the eastern suburbs with the city center and was one of only two East Berlin subway lines before German reunification, date back to the 1990s.