The new metro line of Istanbul from Kadıköy to Kartal is 21.7km long with new 16 underground stations. The line is completely underground, with a variable cover equal to 20-40m and its construction involved the use of all available tunneling technologies including conventional methods, cut and cover, and mechanized techniques. All the stations (platform and connection tunnels of the stations), the switch tunnels and more than 50% of the running tunnels were excavated using conventional tunnelling methods. The alignment also includes 9 cross-over caverns (twin tunnels with the pillar removed), more than 20 access tunnels for the construction phase, about 60 shafts for ventilation and elevators near the stations and several connection tunnels.

Detailed Design of the tunnels and underground stations and Construction follow-up of all the underground works (except for the running tunnels excavated with TBM).