Marmaray railway project. Istanbul. Turkey





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The Marmaray Project consists of connecting Istanbul’s Asian and European sides through a railway tube tunnel under the Bosporus strait.

The project starts on the European side, in Halkali, crosses the Bosphorus and ends on the Asian side, in Gebze. The total length of the railway is 76 kms, of which 63 kms run on the surface with three tracks and the other 13 kms, under a tunnel with two tracks.

The project includes the construction of 6 traction substations (154 kV / 1x27.5 kV ac) for the power supply to the catenary: Halkali with a power of 2x21 MVA, Veliefendi with a power of 2x34 MVA, Ibrahimaga with a power of 2x33 MVA, Idealtepe with a power of 2x27 MVA, Pendik with a power of 2x27 MVA and Osmangasy with a power of 2x20 MVA. In addition, to ensure the supply during the construction phase, another provisional substation with a power of 2x7 MVA has been installed.

EyM has been the manager for the design of OCS (overhead catenary system), as well as the supply, assembly, testing and commissioning (EPC).

There are two types of catenary in the project

  • Rigid catenary: 26 kms inside the tunnel (two tracks)
  • Flexible catenary: in the sections that run on the surface (three tracks)

In addition, EyM has supplied, installed and started up a power generator plant to feed the tunnel catenary in case of a power supply failure, in order to be able to evacuate the trains inside the tunnel to the closest stations. It is a 5 MVA power plant which generates three-phase alternating current and feeds the catenary at 1x25 kV.