Marmaray Project: Gebze-Halkali Commuter Rail Upgrading, Istanbul (Turkey)

The works include the full design, complete removal of two existing tracks and their replacement with three new tracks
Sector Railways (Transport)
CountryTurkey (Europe)


The Marmaray project in Turkey consists in developing connections of rail lines, between the European and the Asian continents, in Istanbul through an underwater tunnel under the Bosporus Strait. This tunnel will allow the transit of high-speed commuter and freight trains between the two continents.

The purpose of Marmaray Project is to provide bi-directional, safe, robust, reliable, comfortable, durable, cost-effective and uninterrupted train transportation of passengers and freight through the Istanbul area and the Bosphorus Strait, as well as on both European and Asian side. This new improved railway system is expected to have a design life of at least 100 years.

Technical Data:

The capacity in passengers in this service at peak-hours is not less than 75,000 passengers per hour per travel. The loading capacity for freight trains is around 25 tonnes. The design speeds are 100 kilometres per hour for passenger trains and 60 kilometres per hour for freight trains.

The works contracted includes the full design, complete removal of two existing tracks and their replacement with three new tracks.

The total length of the proposed track system is approximately 76 km, sub-divided as follows:

  • 20 km of surface line from Halkalı to Yedikule on the European side:
  • 13 km of tunnel line from Yedikule to Sögütlüçesme beneath the Bosporus Strait (other contract),
  • 43 km of surface line from Sögütlüçesme to Gebze on the Asian side.

The main structures and systems include:

  • 3 new underground stations and 37 surface stations (renovation and upgrading)
  • Operations control centre
  • Depots, yards, workshops, maintenance facilities
  • Upgrading of existing tracks including a new third track on ground
  • New electrical and mechanical systems
The travel time between Gebze and Halkali with the existing commuter rails and ferries is about 185 minutes; with the new and upgraded uninterrupted commuter rail this time will come down to 104 minutes.


  • Preliminary, Basic and Detailed Design
  • Technical drawings in accordance with the identified design stages
  • Preparation of technical specifications for the manufacture, fabrication, installation and construction
  • of all systems and structures
  • Site Survey and investigation of existing structures, reporting