At 10:18 a.m. on July 14, the Taichagou No. 1 Tunnel on the Lanwu section of the Lanzhou-Zhangye Third and Fourth Railway Line was successfully holed through, marking major progress in the construction of the Lanzhou-Zhangye Third and Fourth Line.

The Taichagou No. 1 Tunnel is located in Zhongbao Town, Yongdeng County, Gansu Province. With a total length of 898.74 meters, it is a double-track tunnel with a maximum burial depth of 85 meters and a minimum burial depth of 21 meters. The tunnel lies in a loess gully area with considerable topographic variation. The entire tunnel passes through Grade V surrounding rock, making construction highly difficult; it is one of the key and difficult control projects along the entire line. The project is agent-constructed by China Railway Lanzhou Group Co., Ltd., managed for construction by the Lanzhou Engineering Construction Command, constructed by China Railway 21st Bureau Group, and supervised by Gansu Tieke Supervision Company. Since construction began on May 10, 2020, all participating units have strictly followed the requirements of "ensuring safety, grasping quality, and promoting progress." In response to construction difficulties such as complex surrounding rock, they adopted the three-bench temporary cross-brace method and the three-bench reserved core soil method, and carried out single-direction excavation from the entrance to the exit.

The newly built Lanzhou-Zhangye Third and Fourth Railway Line has a total length of about 518 kilometers and a design speed of 250 kilometers per hour. It starts from Lanzhou West Station in Lanzhou City, passes through Wuwei City and Jinchang City, and finally leads into Zhangye West Station in Zhangye City. Intermediate stations include Zhongchuan Airport Station, Shilakou, Yongdeng West, Tianzhu West, Heisongyi, Gulang North, and Wuwei East. It runs through the Hexi Corridor, the golden section of the ancient Silk Road. Once completed, the railway will become the second high-speed rail corridor from Lanzhou to Xinjiang, improve the layout of the high-speed railway network in western Gansu Province, and promote the formation of a rapid passenger transport corridor in the Hexi Corridor of Gansu Province.