The first machine, a 6.56m-diameter EPB will bore the Mecidiyekoy to Mahmutbey (M7 Line) that will be 18km long and serve 15 stations when it enters service in 2017. Terratec said the design of the cutterhead is versatile to deal with the mixed geology expected on the project. The contractor is a joint venture of Gülermak, Kolin and Kalyon.

The second TBM is a 5.74m-diameter hard rock double shield machine, and will be utilised by tunnelling subcontractor Seli Overseas to bore an 11.5km headrace tunnel and install hexagonal concrete segments. Geology will primarily consist of the siltstones, sandstones and conglomerates of the Champa Formation, and the mudstones and siltstones of the Tholam Formation. The overall project is being developed by main contractor SK Engineering and Construction.