Istanbul Marmaray Project

The idea of a railway tunnel under the Istanbul Strait was first raised in 1860. However, where the tunnel under the Istanbul Strait crosses the deepest parts of the Strait, the old-fashioned techniques would not allow the tunnel to be on or under the seabed, and therefore the design indicated a "floating" type of tunnel placed on pillars constructed on the seabed.  

The Marmaray Project is the upgrading of approximately 76 kilometers of commuter rail from Halkalı to Gebze. The red alignment on the map shows the parts of the railway that are above ground and the white alignment shows the new railway system that will be constructed in tunnels under the Istanbul Strait.

Istanbul is a city where historical and cultural values must be preserved and at the same time modern railway facilities have to be installed to decrease the environmental impact of public transportation and increase the capacity, reliability and comfort of the railway systems

The Project provides an upgrading of the commuter rail system in Istanbul, connecting Halkalı on the European side with Gebze on the Asian side with an uninterrupted, modern, high-capacity commuter rail system.

Railway tracks in both sides of Istanbul Strait will be connected to each other through a railway tunnel connection under the Istanbul Strait. The line goes underground at Yedikule, continues through the Yenikapı and Sirkeci new underground stations, passes under the Istanbul Strait, connects to the Üsküdar new underground station and emerges at Sögütlüçesme.

This Project is one of the major transportation infrastructure projects in the world at present. The entire upgraded and new railway system will be approximately 76 km long. The main structures and systems; include the immersed tube tunnel, bored tunnels, cut-and-cover tunnels, at – grade structures, three new underground stations, 37 surface stations (renovation and upgrading), operations control centre, yards, workshops, maintenance facilities, upgrading of existing tracks including a new third track on ground, completely new electrical and mechanical systems and procurement of modern railway vehicles.

yes most deep tunnel in the world.55 metres; many unique contains… i really interested cause i am civil engineer. amazing project, i ever seen… i wish to be nice .       hayırlıs olsun :)

looks good