An attendant shows an oxygen cylinder on the train Z722 from Changchun of northeast China's Jilin Province to Lhasa of southwest China's Tibet Autonomous Region, June 16, 2016. The Z722 and Z21 trains from Changchun to Lhasa are equipped with oxygen supply equipments for passengers. They used 25T air conditioner train and started to operate on Feb. 26

source : xinhua