Linzhi Railway starts from Dailin Village, Zhan Jie Town, qingzhen city, Guiyang, and passes through Dai Lin, Acropolis, Liu Chang, Ziqiang, Huaqi, Puweng, Sanjia and Chengguan to Zhijin Station. It has a total length of 99.5 kilometers and a total investment of 4 billion RMB. The Linzhi Line passes through areas with high mountains and deep valleys, rugged terrain, obvious karst landform development and great construction difficulty. There are 6 bridges1bridge and 46 tunnels on the 99 km line, with a bridge-tunnel ratio of 65%. The main control project is Najie River Bridge, which is located at the junction of Miao Township in Liu Chang, qingzhen city and Qiangzi Township in zhijin county, and spans the Najie River Grand Canyon. The pier height is103m and the main span is 65438+. The pier of Yangliuhe Bridge is105m high and its main span is128m. There are three extra-long tunnels. Ping Zi Upper Tunnel is 6302 meters long, which is the longest tunnel in the whole line. Caijiazhai Tunnel is 3 108 meters long and Dachaipo Tunnel is 3029 meters long. Among them, Najie River Bridge is the most difficult project in the whole line. It crosses Najie River, a tributary of Wujiang River, with a total length of 8 10/0m, a main span of 352m and a distance of 320m from the water surface. It is the first concrete filled steel tubular arch bridge with the longest span in China. At present, its height exceeds that of Beipanjiang Bridge, a Shanghai-Kunming high-speed railway built on Beipanjiang Gorge in Qinglong County, Southwest Guizhou Province, with a height of 300 meters. After the hard work of railway workers, Najiehe Bridge was successfully closed in August 20 14. Due to the extremely difficult construction conditions and complex terrain, the construction of some sections is slow, and the line is expected to be completed and opened to traffic in August 20 15.