Maintenance workers offer safety guarantee for normal operation of subway in Shanghai

Maintenance workers for the electricity system of subway, work at the Jiuting station of subway line 9 in east China's Shanghai Municipality, June 5, 2018. The group of electricians check and maintain the electric system within the section usually at night after the last train. Their work offers safety guarantee for the daily normal operation of subway. (Xinhua/Ding Ting)