Originally Posted by heathius
I'm afraid that the only way to get any accurate information would be to go to the Xi'an or Beijing train stations and ask.
Chinese train stations hold a special place in my heart adjacent to the DMV place (in my heart); they are, hands down the least pleasent part of train travel (actually, waiting in the Beijing station taxi queue at 7a in Jan is the single worst part of the experience, but I digress).
In any event, as a general rule, I try to keep train station visits to an absolute mimimum. In other words, I don't go unless I'm actually taking a train. Fortunately, in most cities, it is possible to buy tickets elsewhere.
And even when this is not the case, it's well worth a few kuai to delegate the ticket purchasing task to a third party. Hotel concierges are quite useful in this respect. Tell them where you want to go, let them get on the phone, give them money, and spend your time engaging in more pleasent activities.