A railway staff member overhauls the catenary equipment of Karamay-Tacheng Railway in northwest China's Xinjiang Uygur Autonomous Region, May 21, 2021. Random light objects such as broken kites, floating balloons, and drifting plastic films pose significant threats to the safe operation of high-speed railway lines, affecting the order of the railway network or causing irreversible damage to the overhead contact system equipment at worst. The duty of a group of railway staff members is to regularly patrol the routes to clean off these objects from the railway grid in time. (Photo by Duan Yanan/Xinhua)

A railway staff member cleans the fence along the railway near the Pingtan Strait Road-rail Bridge in southeast China's Fujian Province, May 25, 2021. (Photo by Duan Yanan/Xinhua)

Railway staff members pick up light objects near a railroad section in Nanning, south China's Guangxi Zhuang Autonomous Region, May 26, 2021. (Photo by Duan Yanan/Xinhua)

Aerial photo taken on May 26, 2021 shows railway staff members replacing the hanging strings of the overhead contact system at a railroad section in Nanning, south China's Guangxi Zhuang Autonomous Region. (Photo by Duan Yanan/Xinhua)

Railway staff members assemble a ladder during a drill in Nanning, south China's Guangxi Zhuang Autonomous Region, May 25, 2021. (Photo by Duan Yanan/Xinhua)

Railway staff members assemble a ladder during a drill in Nanning, south China's Guangxi Zhuang Autonomous Region, May 25, 2021. (Photo by Duan Yanan/Xinhua)