Originally Posted by
jiejie
For the fast trains (G's), I wouldn't worry about it as long as you are past the holiday period and have a little flexibility. In mid-September, I was able to walk up to the automatic kiosks in the train stations at Nanjing and Suzhou, and get the next train out.
While I agree that train tickets around the Yangtze Delta are often easy to snag on the spot, they do sell out on occasion (typically not the entire schedule, but 2-3 hour waits are fairly common), and this is a relatively easy contingency to insure against (either pay your hotel a few bucks or visit a remote ticket office).
As you must know by now, my travel related risk tolerance is abnormally high. However, I've spent enough time (unnecessarily) waiting around airports and train stations to prompt a small amount of planning in situations like the OP's.
BTW, I also think first class is usually worth an extra $5-15.