Subway train assembly plant employees work at a site in Tehran, Iran, September 4, 2016. The plant is a branch of Tehran Wagon Manufacturing Co, a joint venture between Iran and China's CNR Changchun Railway Vehicles Co and the NORINCO International Cooperation Co. At present, Tehran's five subway lines, all built by Chinese companies, are in service. The building of Line 6 is also being constructed by Chinese companies and will be completed later this year, with the project costing $1.2 billion. [Photo/Xinhua]