Third tunnel to connect the European and Asian sides of Istanbul under the Bosporus announced

Updated plans for the construction of the Great Istanbul Tunnel were announced by Turkey’s Transport and Infrastructure Minister, Adil Karaismailoğlu, on Wednesday.

The Great Istanbul Tunnel will be the city’s third crossing under the Bosporus, following the 3.5 km long Marmaray Tunnel and the 5.4 km Eurasia Tunnel.

It was announced that the Great Istanbul Tunnel will be constructed 110m below sea level and have a 19m diameter.

The project will be a multi-use tunnel, connecting the European and Asian sides of the city. More specifically, it will consist of three levels. Two of them are designed to accommodate vehicle traffic, and the third one, a railway system.

The minister stated that the tunnel is scheduled to open in 2028 and will have the capacity to transport 1.3 million passengers daily. The current demand for daily crossings between the city’s Asian and European sides is 2 million passengers, a number which is expected to exceed 3 million in the future.

Karaismailoğlu explained that the railway component will span a total length of 28 kilometers and consist of 13 stations, connecting with 11 other railways and the Metrobus line. The railway will have the capacity to serve 70,000 passengers per hour in one direction and the journey will take approximately 42 minutes.

Finally, the Tunnel Boring Machine used in this project is one of the largest in the world, having a length of 83 meters and a width of 20 meters.