A staff member works at an overhaul service center for bullet trains in Guiyang, capital of southwest China's Guizhou Province, Jan. 15, 2018. (Xinhua/Liu Xu)

Photo taken on Jan. 15, 2018 shows an overhaul service center for bullet trains in Guiyang, capital of southwest China's Guizhou Province. (Xinhua/Liu Xu)

A staff member works at an overhaul service center for bullet trains in Guiyang, capital of southwest China's Guizhou Province, Jan. 15, 2018. (Xinhua/Liu Xu)

A staff member works at an overhaul service center for bullet trains in Guiyang, capital of southwest China's Guizhou Province, Jan. 15, 2018. (Xinhua/Liu Xu)