Chengdu–Kunming railway

The Chengdu–Kunming railway or Chengkun railway (simplified Chinese: 成昆铁路; traditional Chinese: 成昆鐵路; pinyin: chéngkūn tiělù), is a major trunkline railroad in southwestern China between Chengdu, the capital of Sichuan Province and Kunming, the capital of Yunnan Province. The line runs through the Dadu River and Anning River basins in southwestern Sichuan, which are enclosed by high mountains, canyons and major rivers, and the Longchuan River basin in northern Yunnan. It crosses a major geological fault zone. The mountains along the line are steep and the terrain and geology are extremely complex.

The idea of building a railway between Chengdu and Kunming originated in the late 19th century, but concrete surveys were not conducted until the 1930s and 40s. However, the project was ultimately thwarted by the rugged mountains between Sichuan and Yunnan provinces. Surveys began in the early 1950s, and after comparing and evaluating three main route options—western, central, and eastern—the western route was ultimately chosen due to factors such as the Panzhihua steel base and the natural resources along the route. Construction began in the summer of 1958, but was halted after the completion of the Chengdu-Qinglongchang section in early 1960. Construction resumed in 1964 as a key project of the Third Front construction. The Cultural Revolution subsequently hampered progress in the section under the Second Railway Bureau, but normal construction resumed at the end of 1969.