First railway goes abroad

The 859-kilometer Yunnan-Vietnam railway is the province's first railway. It went into operation in 1910, to connect Kunming with Haiphong of Vietnam. It is still in use today. The first railway connecting Yunnan with other Chinese provinces was the Guizhou-Kunming Railway, which was completed in 1966. Today, Yunnan is building more railways to improve connections with other countries. Construction of the China-Laos Railay, from Kunming in the north to Vientiane in the south, is accelerating and will go into operation in 2021.

Due to the mountainous terrain and complicated history, three different railway gauges were once in use at the same time in Yunnan. The Yunnan-Vietnam railway adopted the one meter gauge. The Gejiu-Bisezhai-Shiping railway, built in the sameperiod as the Yunnan-Vietnam railway, had a track gauge of just 60 centimeters. After the founding of the New China, Yunnan began to build the 143,5-centimeter gauge railway. Today, trains in the province can run as fast as 300 kilometers per hour.

The most difficult tunnel in China

The Dazhushan tunnel is a critical project on the Dali-Ruili railway, with a total length of 14.5 kilometers and a maximum underground length of 995 meters. Construction started in 2008, and was expected to be completed in five years. Soon, however, engineers discovered that the tunnel had to traverse six fault zones. Other challenges included radiation, high temperatures and frequent geological disasters. At some stretches, the mountain massifs were as fragile as tofu. On June 26th, 2019, after eleven years of hard work, the tunnel's parallel heading was holed through, laying a solid foundation for the completion of the tunnel in 2020. It is considered the most difficult tunnel in China to date.