Vienna U-Bahn Editorial Photo

The first section of the modern U-Bahn opened on 8 May 1976, but two of the lines extended and later designated as U-Bahn (U4, U6) date back to the Stadtbahn (city railway) system, which first opened in 1898. Parts of both the U2 and U6 originate from subway tunnels built to accommodate earlier tram lines. Only the U1 and U3 were built wholly as new subway lines. Lines are designated merely by a number and the prefix U (for U-Bahn) and identified on station signage and related literature by a colour. There are currently five lines; U1, U2, U3, U4 and U6. Since the late 1960s there have been numerous suggestions of routings for a line U5 but all these projects have been shelved, until the construction of a new U5 has been announced in early 2014.Stations are often named after streets, public spaces or districts, and in some special cases after prominent buildings at or near the station, although the official policy of the Wiener Linien states that they prefer not to name stations after buildings.