Is it possible to purchase a ticket for train departing from different city in China? I may need to buy a ticket in Shenzhen for train travel Guangzhou-Shenyang in case the Shenzhen-Shenyang train sold out. I found the information (http://www.lonelyplanet.com/thorntree/thread.jspa?threadID=1601441) saying yes but it was posted more than two years ago (May 7, 2008). Could someone verify this information still valid?
Thanks.

