ISTANBUL METRO/INTERCITY LINE
Halkali (Europe) – Gebze (Asia)
"MARMARAY CR3" Project
The Marmaray CR3 project encompasses the upgrading and integration of Istanbul’s rail network through the complete refurbishment of existing commuter lines and the creation of a strategic rail link connecting the European and Asian sides of the city via a subsea Bosphorus Strait tunnel.
In June 2017, FS Engineering, in joint venture with SWS, was appointed by the Turkish consortium Kolin-Kaliyon-Cengiz (KKC) to act as the Independent Design Verification Engineer (IDVE) for the construction phase of the Marmaray system.
The project involves the comprehensive upgrading and conversion of the existing suburban railway lines and stations to deliver a three-track infrastructure alignment, configured as follows:
Across the Bosphorus subsea crossing, the alignment transitions to a two-track configuration operating bi-directional mixed traffic. To manage capacity, freight movements are restricted exclusively to a night-time possession window (00:00–05:00) while commuter services are suspended.
The route spans a total length of 76.6 km across 43 stations, connecting 10 districts within Istanbul, with an end-to-end transit time of 115 minutes. When fully operational, the network is designed to achieve a peak capacity of 75,000 passengers per hour per direction (pphpd), supporting an estimated daily ridership of between 1.2 and 1.7 million passengers.
| The project is divided into: 4 CONSTRUCTION LOTS |
| Halkali – Kazlıçeşme (19 km – European side): the entire line was inaugurated on 12 March 2019 and is now considered one of the longest in the world |
| Kazlıçeşme – Ayrılıkçeşme (13 km – Bosphorus crossing) |
| Ayrılıkçeşme – Pendik (19 km – Asian side) |
| Pendik–Gebze |
| INDEPENDENT DESIGN VERIFICATION OF THE TECHNICAL DOCUMENTATION |
Signalling |
Telecommunications |
SCADA - Supervisory Control and Data Acquisition |
Electrical Substations |
Electric Traction |
Trackwork |
Railway Operation |
Systems Integration |
RAMS - Reliability, Availability, Maintainability and Safety |
Depot Facilities |
Rolling Stock Maintenance |
The Marmaray CR3 scheme is an infrastructure project of global strategic significance, seamlessly integrating metro, intercity, and freight operations into a single high-capacity railway network to enhance cross-continental connectivity between Europe and Asia. In its capacity as the Independent Design Verification Engineer, FS Engineering’s technical assurance ensured the highest standards of quality, safety, and reliability throughout the construction lifecycle, showcasing the excellence of Italian engineering expertise in delivering complex, large-scale rail infrastructure.
The IDVE remit continued through to the completion of the core services and the subsequent construction phases required to achieve the final network configuration. The works were completed in October 2020, with provision made for potential extensions to the scope of activities.