Aerial photo taken on July 2, 2018 shows maintenance workers checking and repairing freight trains in Jilin City, northeast China's Jilin Province, July 2, 2018. Yu Guodong, a railway maintenance worker, is in charge of cleaning tanker cars of the freight train carrying combustible liquids. The cleaning of each tanker takes 30 minutes. Maintenance workers work inside the tankers, where the temperature sometimes reaches 60 degree Celsius in summer. Dressed in fire-retardant clothing, Yu needs to clean more than 20 tanker cars a day in the scorching summer heat, to ensure the safety of railway transportation. (Xinhua/Xu Chang)