Marmaray – The Tunnel Under Crossing Bosphorus.

Marmaray is finally in use of Istanbul as the fastest connection of Europe and Asia. It consists of the construction of an undersea rail tunnel under the Bosphorus as well as the modernization of suburban rail lines along the Sea of Marmara from Halkalı on the European side to Gebze on the Asian side.

Construction started in 2004, with an initial target opening date of April 2009. After multiple delays due to archaeological findings, opened on October 29, 2013.

The name Marmaray (Mar-ma-rai) comes from combining the name of the Sea of Marmara, which lies just south of the project site, with ray, the Turkish word for rail.

Marmaray was built by 1343 engineers and thousands of workers. 875,000 cubic meters of cement, 145,500 tones of steel, and 27,800 meters Rail road were used.

5,5 bil. USD investment was made. It connects 2 continents to each other in 4 minutes.

Marmaray, eventually, will connect Beijing (China) to London (England) with fast train track.

Some figures of the project are as follows :

Overall length : 76.3 km (47.4 mi)

European side : 19.3 km

Asian side : 43.4 km

Tunnel section : 13.6 km (8.5 mi)

Immersed tube : 1,387 m (4,551 ft)

Deepest point : 60.46 m (198.4 ft)

Minimum curve radius : 300 m (980 ft)

Maximum gradient : %1.8

Surface stations : 37

Underground stations : 3

Interchanges : 4

Inter-city stations : 8

Minimum platform length : 225 m (738 ft)

Average station spacing : 1.9 km (1.2 mi)

Maximum speed : 100 km/h (62 mph)

Commercial speed : 45 km/h (28 mph)

Headway : 2-10 minutes

Passengers per hour and direction : 75,000

Number of passenger cars : 440

Travel time total between Gebze and Halkali : (New and upgraded uninterrupted commuter rail) 104 minutes