Hello, sir, if you need to catch a flight from Beijing on Jan.19, you would better take the train from Xining on Jan.18 or before, as there are only two trains from Xining to Beijing by costing around 22hrs. And the train from Xining arrives at Beijing West Train Station, where many hotels are surrounded, such as Beijing Railway Hotel (West Railway Station), Orange Hotel (Tianningsi), Beijing and etc. From the west railway station, you could take a taxi to the Gongzhufen station first and then take the airport bus to the airport, which is around 40kms.