A massive tunnel project is in progress to establish a connection between Europe and Asia, facilitating the daily transportation of approximately 1.3 million individuals. This innovative tunnel, named The Great Istanbul Tunnel, will span 6.5 km (4 miles) linking the European and Asian sectors of Istanbul. With an estimated cost of £2.8 billion, the tunnel is anticipated to be operational by 2028.
Turkey is heavily investing in upgrading its transportation infrastructure, aiming to enhance its domestic economy. The tunnel will pass beneath the Bosphorus, a critical 30-km waterway in Turkey that joins the Black Sea and the Sea of Marmara, serving as the boundary between Europe and Asia. The tunnel will be the third crossing under the Bosphorus, following the Marmaray Tunnel (3.5km) and the Eurasia Tunnel (5.4km). The construction is employing one of the world’s largest tunnel boring machines, measuring 83m in length and 20m in width.
At a depth of 110 meters below sea level, the tunnel will have a diameter of 18.8 meters, accommodating both cars and trains across three tiers. It will connect Istanbul’s three major airports and link with 11 other railways, optimizing the functionality of the city’s Metrobus line. The railway section of the tunnel will feature 13 stations, catering to 70,000 passengers per hour in a single direction.
The primary objective of The Great Istanbul Tunnel is to boost trade and tourism between Europe and Asia, foster job creation, and spur economic growth in Turkey. Additionally, it aims to alleviate traffic congestion in Istanbul, leading to an improved quality of life for residents and reduced environmental pollution. The project was formally announced by Prime Minister Ahmet Davutoğlu in 2015, with Minister Karaismailoğlu highlighting the reduced rail travel times across the Bosphorus to just over 40 minutes.
According to insights from New Civil Engineer, the necessity for the tunnel project is substantiated by projections indicating a future daily crossing of more than three million individuals between the European and Asian sides of the river, surpassing the current two million daily crossings.