Engineers examine rail every night to ensure safety in Urumqi, NW China

Worker Yan Yangyang checks rails by measuring the width between rails at the Xinjiang section of Lanzhou-Xinjiang high-speed railway in Urumqi, northwest China's Xinjiang Uygur Autonomous Region, Feb. 5, 2018. Engineers examine the rail every night to ensure the safety of trains and passengers. (Xinhua/Hu Huhu)