![Workers build the New Badaling tunnel of the Beijing-Zhangjiakou high-speed rail line in Beijing, capital of China, Dec. 13, 2018. Workers have achieved a major breakthrough in the Beijing-Zhangjiakou high-speed rail line project, after they dug through the New Badaling tunnel, a pivotal part along the line, on Thursday. (Xinhua/Xing Guangli)](http://www.ecns.cn/hd/2018/12/14/2c1c10ca34124e808ca0c46ccbe90158.jpg)
Workers build the New Badaling tunnel of the Beijing-Zhangjiakou high-speed rail line in Beijing, capital of China, Dec. 13, 2018. Workers have achieved a major breakthrough in the Beijing-Zhangjiakou high-speed rail line project, after they dug through the New Badaling tunnel, a pivotal part along the line, on Thursday. (Xinhua/Xing Guangli)
![Workers celebrate as they cut through the New Badaling tunnel of the Beijing-Zhangjiakou high-speed rail line in Beijing, capital of China, Dec. 13, 2018. Workers have achieved a major breakthrough in the Beijing-Zhangjiakou high-speed rail line project, after they dug through the New Badaling tunnel, a pivotal part along the line, on Thursday. (Xinhua/Xing Guangli)](http://www.ecns.cn/hd/2018/12/14/4a5e638289cc42349446fa014c46a9d0.jpg)
Workers celebrate as they cut through the New Badaling tunnel of the Beijing-Zhangjiakou high-speed rail line in Beijing, capital of China, Dec. 13, 2018. Workers have achieved a major breakthrough in the Beijing-Zhangjiakou high-speed rail line project, after they dug through the New Badaling tunnel, a pivotal part along the line, on Thursday. (Xinhua/Xing Guangli)
![Workers celebrate as they cut through the New Badaling tunnel of the Beijing-Zhangjiakou high-speed rail line in Beijing, capital of China, Dec. 13, 2018. Workers have achieved a major breakthrough in the Beijing-Zhangjiakou high-speed rail line project, after they dug through the New Badaling tunnel, a pivotal part along the line, on Thursday. (Xinhua/Xing Guangli)](http://www.ecns.cn/hd/2018/12/14/dc8bd29f0e9e4f9684c3245314dabea4.jpg)
Workers celebrate as they cut through the New Badaling tunnel of the Beijing-Zhangjiakou high-speed rail line in Beijing, capital of China, Dec. 13, 2018. Workers have achieved a major breakthrough in the Beijing-Zhangjiakou high-speed rail line project, after they dug through the New Badaling tunnel, a pivotal part along the line, on Thursday. (Xinhua/Xing Guangli)