There is hourly lounge in the arrival Hall. You can get to the BUseniss Center in the Arrival Hall to ask for a rest room. The price seems to be 60RMB per hour. There are no others ways at the time to the railway station but aitport night bus and taxi. I suggest you take the night bus to Zhejiang Middle Road/huashan Road. Then take a taxi to the railway station. The night bus is available till the last flight of that day. So, if you can not find the bus when you get off the lounge, you have to take taxi.