CHANGSHA SOUTH RAILWAY STATION

In total, there are about 32 men service ticket counters and 42 ticket vending machines. No matter which tikcet counter or vending machine, you can book the train tickets 6 days before.
The time of picking up paper trian tickets depends on how many people there are at the railway station. When I was there, I only use about 10 minutes to queue and then get my ticket.
You can book the ticket, pay and get the paper train ticket 6 days before from CS to Guanzhou.