The Marmaray railway public transportation system was opened in 2013 in Istanbul. Transportation has been a major problem for Istanbul for many years, especially transportation between the two sides of the city - Asia and Europe - has been a real challenge. Before Marmaray has been implemented the two sides have been connected only by highways (2 Bosporus bridges) and sea transit ferries. The high-tech construction methods used for the Marmaray project helped creating smart solutions for specific challenges in cities. The project was planned already back in 1860, however only today’s technology made it possible to construct and operate it. In the further steps of the project, Marmaray will be connected to the existing railway system of the city. It enables to pass the Bosporus in 4 minutes and to transport 75,000 passengers per hour (Yenikapi station).