Marmaray Project. Istanbul. Turkey

The Marmaray Project consists of the connection of the railway networks of the city of Istanbul, European and Asian side, through the construction of a submarine tunnel crossing the Bosphorus Strait.

The project starts on the European side at Halkali, crossing the Bosphorus, and ends on the Asian side at Gebze. The total length of the project is 76 km, of which 63 km are above ground with three tracks and the remaining 13 km under tunnel with two tracks.

For catenary power supply, six traction substations (154 kV/1×27.5 kV a.c.) are built along the route: Halkali with a capacity of 2×21 MVA, Veliefendi with a capacity of 2×34 MVA, Ibrahimaga with a capacity of 2×33 MVA, Idealtepe with a capacity of 2×27 MVA, Pendik with a capacity of 2×27 MVA and Osmangasy with a capacity of 2×20 MVA. In addition, to guarantee supply during the construction phase, another temporary substation with a capacity of 2×7 MVA has been installed.

EyM has been responsible for the design of the OCS (catenary), as well as its supply, assembly, testing and commissioning (EPC). There are two types of catenary in the project:

• Rigid catenary: 26 km for the tunnel (two tracks)
• Flexible catenary: on the surface sections (three tracks)

In addition, EyM has supplied, installed and commissioned a generator plant to power the tunnel catenary in the event of a power failure in order to evacuate the trains inside the tunnel to the nearest stations. It is a plant with an installed power of 5 MVA, which generates three-phase alternating current and feeds the catenary at 1×25 kV.