An expansion project has started at Delingha Station on China's Qinghai-Tibet Railway, the world's highest and longest plateau railroad.

The work marks the official start of a quality improvement project on the railway's Xining-Golmud section, which spans more than 759 kilometers and plays the pivotal role of connecting the plateau with the outside.

The improvement and expansion of this section is expected to be completed by the end of next year. The travel time between Xining and Golmud will be reduced to less than five hours after the renovation.