Technicians checks a tram designed for high-altitude region at the CRRC Qingdao Sifang Co in Qingdao, a coastal city in East China's Shandong province, May 10, 2018. China's first tram that will be used on Qinghai-Tibet Plateau rolled off the production line on May 9 in Qingdao. With a maximum speed of 70 kilometers per hour, the two-carriage tram is capable of carrying 168 passengers. The tram line is expected to be put into operation in Delingha, capital of the Haixi Mongol and Tibetan autonomous prefecture in Qinghai province this year. [Photo/Xinhua]

Technicians checks a tram designed for high-altitude region at the CRRC Qingdao Sifang Co in Qingdao, a coastal city in East China's Shandong province, May 10, 2018. China's first tram that will be used on Qinghai-Tibet Plateau rolled off the production line on May 9 in Qingdao. With a maximum speed of 70 kilometers per hour, the two-carriage tram is capable of carrying 168 passengers. The tram line is expected to be put into operation in Delingha, capital of the Haixi Mongol and Tibetan autonomous prefecture in Qinghai province this year. [Photo/Xinhua]