The Bosphorus tunnel connects people at the heart of Turkey’s most vibrant metropolis
The EIB is taking part in one of the world's most ambitious urban transport schemes, known to the people of Istanbul as the Marmaray project: the development of a modern, high-capacity commuter rail system providing an effective transport solution for the citizens of Istanbul via a tunnel under the Bosphorus, and connecting the Asian and European sides of Istanbul. This will also enable the passage of high-speed trains to bring both parts of the city and the two continents closer together. First signed by the Bank in 2004, the crucial relevance of the EIB-supported project in terms of a transport network, as well as in forging closer ties between Turkey and the EU, was already realised by all the actors involved from its inception. It is the largest and most important infrastructure project undertaken in Turkey.
Istanbul is the country's economic engine and serves as a commercial and financial hub. Its metropolitan area is emerging as one of the largest in Europe, but its transport infrastructure struggles to keep up. The city's transport system is challenged by the accelerated pace of growth witnessed over the past few years. More than 12 million people live here and it attracts many more from outside who come to work in the city every day. The Bosphorus is the natural connection between the Mediterranean and the Black Sea, and between the European and Asian continents, but at the same time it is a natural barrier cutting the city in two. Each day, over a million trips are made across the Bosphorus by boat or using one of the two bridges over the straits. At rush hour, crossing the city can take up to five hours. The Marmaray rail link will provide a long-sought mass transport system and help to overcome the city's natural divide. The benefits are clear: reducing air and noise pollution by enabling a major shift from road to rail and alleviating congestion on the road network. Once it is operational, the new transport link is likely to attract more than 1.5 million passengers using the tunnel per day. The Marmaray project is also expected to result in a reduction of 144,000 tonnes of air pollution and greenhouse gases annually.
Building an intercontinental link
The tunnel will link the two railway lines on the so-called Pan-European Transport Corridor on either side of the Bosphorus. With a total length of 76.5km, the project includes the construction of 13.6km of double track tunnel, of which more than 1.3 km under the sea, and an additional third track on a length of over 62km connecting to other transport networks. Taking the project to another level, the EIB is additionally supporting the setting-up of a transport link of strategic importance by helping to finance the building of Turkey's first high-speed connection between the two major metropolises of Istanbul and Ankara.
The Marmaray project is the first of its kind, with no precedent in terms of its size and sophistication. Never before has an immersed tunnel been built at a depth of 60 metres, with the marine construction equipment for dredging and immersion of the tunnel elements operating in the congested shipping lanes and heavy currents of the Bosphorus. Underground stations and tunnels are being built underneath historical buildings in the densely populated urban areas of Istanbul. Ground settlements from the tunnel excavations risk resulting in severe consequences for people and buildings above ground unless they are carefully controlled at each and every step. A modern railway - the commuter rail system - is being fitted into an existing, narrow railway corridor right through the city. "The Marmaray is a huge, extremely complex and exciting project - I can't think of any challenge this project lacks," says Jens Peter Henrichsen, Project Manager from Avrasyaconsult, the joint venture preparing the project and overseeing the construction.
The Marmaray project is positioned in a very active seismic zone. Over the past few years, it has brought together seismic experts from Japan, the US and Turkey to build underground structures and a tunnel under the Bosphorus that will be safe even in the event of an earthquake. The immersed tunnel beneath the Bosphorus strait has now been completed along with many kilometres of tunnels on land.
Rewriting Istanbul's history
During the works on the Yenikapi station, which is to become one of the main hubs for traffic across the city, workers discovered that they had not been the first to start building at this site. What they found, bringing an ancient Theodosian harbour beneath the city to light, was a historical treasure from the Byzantine period. An armada of shipwrecks was lifted from the grounds of where one day the commuter rail and metro stations will be built. Archaeologists were able to secure 33 ships from the Theodosius port, a Byzantine church and thousands of artefacts from the historical site - enough to fill an entire museum. The findings forced historians to rewrite the books: whereas the beginnings of the city of Istanbul were previously believed to date back 2 700 years, the findings from the archaeological excavations revealed that the history of Istanbul stretches back some 8 500 years. Despite the delays that these findings have caused to the project, their cultural value is unique. "These archaeological findings would have not been possible if it were not for the Marmaray project and its engineers," Dr Ufuk Kocabaş from Istanbul University underlines.
"Marmaray was a typical project to receive support from the Bank, as it is an infrastructure undertaking with clear benefits to be gained, and which connects the people of Europe," explains Hakan Lucius, the Bank's loan officer in charge at the time. The year 2004 became a turning point as regards Turkish-EIB relations when the Bank decided to sign up to what would be its largest contribution to a single project outside the EU. The EIB is cooperating in financing the project with the Japanese Bank for International Cooperation, the Council of Europe Development Bank and the Republic of Turkey. More specifically, the Bank helped to finance this milestone transport link through the Bosphorus tunnel providing an urban commuter rail link, as well as a rail connection between Europe and Asia for InterCity and freight trains. The EIB can now look back on more than 45 years of lending activity in Turkey, which to date remains the largest recipient country of financing outside the EU.
Next station: Marmaray express
The Marmaray project still has a way to go before it will become operational as the historical findings came as a stumbling block. But knowledge of the history of Istanbul has been changed forever by this project. "In Istanbul we live on archaeology and we live in history," Huseyin Belkaya, Deputy Project Manager from Avrasyaconsult explains. "This tunnel will be built. Of course it will be a little bit delayed, but we have waited for around 147 years to construct this tunnel - we can wait a couple of years more."