The U2 is an underground line in Nuremberg, opened on 28 January 1984 and the last station along the line to open was Flughafen (Airport) in 1999. The line is about 13.1 kilometres (8.1 mi) long and has 16 stations; the termini are Röthenbach and Flughafen. Since 2010 all trains in regular operations are run driverless. At 2,388 metres (7,835 ft) the stretch between Ziegelstein station and Flughafen station is the longest interval between two stations in the network and the only single track section on any subway line in Germany (both stations have two platform tracks, but the track between the two is single track without passing loops).