Welders examine quality of soldered rails at Xiaolizhuang Welding Base of Mechanical Works Section of Zhengzhou Railway Bureau in Zhengzhou, capital of central China's Henan Province, May 4, 2017. A total of 135 welders at the base are working to weld 100-meter-long steel rails into 500-meter-long rails for high-speed railway. Since 2008, the base has provided rail tracks for China's high-speed railway with a total length of over 2,000 kilometers. (Xinhua/Li An)
