The Tunnel Under the Bosphorus

Marmaray is a rail line in Istanbul, Turkey. It runs from Halkalı to Gebze along the Sea of Marmara.

The name Marmaray combines the words Marmara and Ray. Ray is Turkish for rail, which saves explaining it twice.

Construction started in 2004. Archaeologists found eight-thousand-year-old artefacts at Yenikapı, delaying the project by four years.

The first phase opened on 29 October 2013. President Erdoğan attended the grand opening ceremony.

The full line opened on 12 March 2019.

The full journey spans from Halkalı to Gebze.

Hyundai Rotem manufactured the rolling stock. The trains use ten-car and five-car electric multiple unit configurations.

Marmaray became the first standard gauge rail connection between Europe and Asia. Steen Lykke noted the project lacked no challenges.