Photo taken on April 11, 2017 shows engineers from China and Argentina working on a train parked for review at the workshops of the Roca Line, in Llavallol, Argentina. Argentina has embarked on an ambitious plan to upgrade its dilapidated rail transport, taking China as a key partner providing both technology and manpower. The Roca Line is the most heavily used within the metropolitan rail network, which serves the capital and surrounding communities. (Xinhua/Martin Zabala)