Originally Posted by
moondog
I suggest you visit a kiosk or ask your hotel to book for you the day before. You can also buy at the train station, but might end up having to wait a while (I'm not too fond of Chinese train stations, for the most part). Also, I don't think any of the Shanghai-Wuxi D trains offer sleepers of any kind (it's only a 40 minute run).
At least one Shanghai-Wuxi D train does offer sleeper. Train D302 departs at 21:20 from Shanghai and arrive in Wuxi at 22:14. One way soft sleeper costs ¥200.00.