In the past 55 years, the construction of the Chongqing Railway was completed on 22 July 1970 (Calendar 20 June 1970), and the construction of the Chongqing Railway was completed on 25 June 1970. The Chongqing Railway was completed on the 58 km route from Chongqing to Qingqing, with a total length of 1,091 km. In 1958, the construction was completed on 22 July 1970, and the operation was completed on 20 December 1970. The line crossed the Chongqing Railway, with a depth of two hundred meters and a "one line" canyon. There are 44 tunnels from Chongqing to Qingqing Railway, with a length of 58 kilometers. From Chongqing to Qingqing 120 kilometers, the four mountains crossed 50 kilometers