Turkey is getting prepared for the big tunnel project which will connect two sides of Istanbul by rail and road. Here are frequently asked questions about the project:

Where it’s going to be constructed?

Big Istanbul Tunnel is planned to be constructed between first and second Bosphorus bridges, under Bosphorus.

Why “big”?

One of the other tunnels under Bosphorus, Marmaray Tunnel, where railway is passing through has a diameter of 7.89 m. The other one, Avrasya Tunnel, has two storeys only for cars, and a diameter of 13.7 m. Big Istanbul Tunnel is planned to have a diameter of 16.8 m. The reason is that the tunnel will have 3 storeys.

What’s the difference between tunnels?

Marmaray Tunnel has only railway pass connecting Sirkeci to Uskudar. The railway is connected to national rail network which allows not only suburban trains, but also freight and passenger trains.

Avrasya Tunnel is now under construction, connecting Harem to Yenikapi. It’ll only for car traffic.

Big Istanbul Tunnel will be both for car traffic and metro line. The top and the bottom is for one-way car traffic and middle storey for double-track metro line.

Why is there a need of new tunnel?

The other tunnels are connecting the transport corridors next to Marmara Sea. However, the main transport corridor of Istanbul connecting denser residential and commercial areas is in the north. Thus, the new tunnel is expected to lighten both the metrobus traffic and the car traffic of both bridges.

Cover Photo: Transport Ministry ©