only one train from Shanghai South Railway Station to Xiamen, which takes over 22 hours. It costs nearly 300RMB for hard sleeper, over 400RMB for soft sleeper. Shanghai long-distance Bus Terminus (1666 Zhongxin Road) has bus to Xiamen, costing about 340RMB. It may need 15 hours. The same when you get back to Shanghai from Xiamen.