Installation of high-speed rail is required to leave no gaps between the tracks. But how to weld a real "seamless rail?” The Shenyang South Welding Rail Base in the Shenyang Public Works Machinery Section in northeast China is the largest factory producing seamless tracks. They developed a cutting machine which is the highest precision in the world. The tracks welded by the factory have reached 12,000 kilometers, and these tracks have been laid into China's high-speed rail network. (Source: Newscctv)