A shunter at Yuanshulin Railway Station in Shanxi province, whose tracks can accommodate up to thirty-two 10,000-metric-ton trains at a time, coordinates coupling and uncoupling as well as the one-to-one pairing of locomotives. Repeating this operation precisely over 80 times a day is what a shunter does to ensure the safety of heavy-haul trains carrying coal on the Datong-Qinhuangdao railway line.