Mainland Chinese with a citizen ID card can register in the official website of the Ministry of Railways (www.12306.cn) to buy a ticket online. So if you have a Chinese friend from mainland China, you can ask your friend to book it for you.
Foreigners can purchase train tickets on Ticket-booking websites such as Ctrip, Fliggy and Qunar. The tickets can be hard to get during the peak season for travel to Tibet, so you are suggested to book ahead of time.
Foreigners can also buy a ticket directly from the train station with a valid passport. But since the train ticket is only available 30 days or less ahead, it can be hard for you to get one during the peak season.
Foreigners can also book the train ticket through a travel agency. Our agency provides train ticket booking service. Please contact us if you need help.