Marmaray is a suburban line improvement project consisting of three sections, the foundations of which were laid in 2004 and under construction, which will connect the European and Asian sides under the Bosphorus. Marmaray is a Eurotunnel-like railway project in the English Channel. Halkalı and Gebze. There are also connections to the Istanbul metro. 1 will shorten the transportation time of millions of people and save energy and time. Bosphorus Bridge and FSM Bridge will also reduce the workload.
When the construction is completed, the line connected to Marmaray, 1,4 km. (Tube tunnel) and 12,2 km. (Drilling tunnel) TBM on the European side of the Bosphorus crossing Halkalı- Sirkeci is planned to be approximately 76 km long on the Anatolian side, between Gebze and Haydarpaşa. The railways on different continents will be joined by submerged tube tunnels under the Bosphorus. With 60,46 meter, Marmaray Project has the world's deepest immersion tunnel used by rail systems. The lifetime of the project is 100 years.