Aerial photo taken on Jan. 11, 2021 shows Yang Yuhai and his colleagues maintaining the railroad switches at Mohe Station in Mohe City, northeast China's Heilongjiang Province. Yang Yuhai, who has worked in the railway system for 30 years, is a team leader of the railroad switches maintenance personnel at the Mohe railway section in Heilongjiang. Mohe is the northernmost city in China, and the temperature at Yang's work site is often below minus 40 degree Celsius in winter. In 2015, he was given a national level award for his excellent work. (Xinhua/Xie Jianfei)