Frankfurt U-Bahn

subterranean rapid transit for the Frankfurt region

The Frankfurt U-Bahn is an underground railway network in the city of Frankfurt, Germany. It is run by the Verkehrsgesellschaft Frankfurt, short VGF. It has 9 lines and a network of 65 kilometers (40 miles) and has exactly 86 stations, apart 27 underground and 59 above ground. Two lines, the U2 and the U3 crosses the city border in Oberursel and Bad Homburg.

The U4 leave the station Bockenheimer Warte
 
U-Bahnnetz Frankfurt 2011