Underwater Railway Links Europe and Asia Together

credit: Fredrick Drevon/TuBygg

Last week an underwater railway opened in Istanbul, Turkey that will allow passengers to travel underwater between Europe and Asia. The Marmaray Tunnel, an 8.5 mile long tunnel located 190 feet below the surface, is expected to shuttle 1.5 million passengers back and forth between the Bosphorus strait. 

Nicknamed the "project of the century", the tunnel was initially proposed by an Ottoman sultan over 150 years ago. Initial plans were designed by architects in 1891 but were never followed through. Due to the archaeological discovery of a 4th century Byzantine port, the project - which began in 2004 and expected to end in 2009 - was delayed four years. 

The opening of the Marmaray Tunnel is only one part of the entire Marmaray project. Completion of the other two segments is expected for 2015. The railway was conceived to reduce automobile congestion in Istanbul but officials hope that the tunnel will become a key part of a much larger railway stretching from Western Europe to China. It has been compared to the Silk Road. 

Due to the high-seismic activity in the area, Turkish officials built the tunnel with earthquake-proof immersed tube and shock-resistant flexible joints. Engineers say it can withstand earthquakes of up to 9.0 on the Richter scale. 

At 190 feet deep, the Marmaray tunnel is the third deepest tunnel in the world, following the Seikan tunnel in Japan (460 feet) and the English Channel tunnel (250 feet).