I have a plan to visit Beijing-Harbin during January 7th-12th, 2010. I would like to take a train from Beijing - Harbin on the 8th, 2010 and come back to Beijing on the 10th. Can I buy the return train ticket at the train station in Beijing. Is it hard to get the ticket at that time? I'm quite worried about the way back to Beijing. Also can I buy the ticket at the agency in Harbin?