China's giant tunnel-boring machine "CREC No. 1294" drilled through the final wall of Istanbul's Sarıyer-Kilyos highway tunnel on Saturday, marking a breakthrough in one of Türkiye's most critical infrastructure projects under the Belt and Road Initiative.

Built by China Railway Group Limited, the machine features a 13.65-meter cutterhead weighing 2,850 tons and advanced continuous excavation technology, designed to overcome the city's deep, high-pressure geological challenges.

The breakthrough was attended by Turkish Transport and Infrastructure Minister Abdulkadir Uraloglu, officially completing the shield section of the tunnel and laying the foundation for the highway's opening to traffic.

"This tunnel-boring machine specifically addresses construction challenges facing the project, as it is located at a very deep level and has high water pressure. The advanced Chinese technology and equipment provide a solid foundation for the smooth progress of the project," said Wang Jianwei, project manager of the China Railway Engineering Equipment Group (CREG).

Upon completion, the Sarıyer-Kilyos highway project will significantly shorten travel time across Istanbul and ease chronic congestion. The CREC No. 1294 arrived in Türkiye in early 2024 and was assembled over 75 days before excavation began in mid-September.

With tunneling tasks scheduled to finish within a year, the breakthrough marks a decisive step toward opening one of the city's most important highway links.