Can a ticket be bought 30 minutes or one hour before departure time? And what is the price or a ticket from Haikou to Chengdu?

It will be late to buy the tickets about 30 mins or one hr before departure as the boarding time is around 40 mins in advance. To ensure getting a seat, you are suggested to book your tickets about 10 days in advance. Besides, one train K486/K487 is running from Haikou to Chengdu with departure time at 18:40 pm each day.