The construction of the underground railway in Istanbul began in 1992. The first line (M2) between Taksim and 4th Levent went into service on September 16, 2000. This line is 8.5 km long and has 6 stations, which all look similar but are in different colors. Currently there are 8 French built 4-car trains in service, which run every 5 minutes on average and transport 130,000 passengers daily. A trip along the entire line takes 12 minutes. The entire subway was built by the cut-and-cover method to withstand an earthquake of up to 9.0 on the Richter magnitude scale.
A northern extension from 4th Levent to Atatürk Oto Sanayi station in Maslak (Ayazaga) entered service in 2009, as well as a southern extension from Taksim to Sishane station in Beyoglu, near the northern entrance of Tünel. The rest of the southern section of the metro, which will run to Yenikapi, across the Golden Horn on a bridge and underground through the old city, is also under construction. At Yenikapi it will provide a connection to the extended light metro and the suburban train.
On the Asian side, construction from Kadikoy to Kartal continues.