Originally Posted by
chornedsnorkack
For your Beijing-Changsha leg, there are 5 express G trains daily, with trip times 5:38 to 5:42. Departing Beijing from 8:00 to 13:02 and arriving in Changsha from 13:38 to 18:41. Ticket price for Beijing-Changsha 2nd class 649 yuan, 1st class 1038 yuan, business class 2050 yuan.
The route also has 11 non-express G trains, trip times 6:31 to 7:38, ticket cost same except 2 trains have VIP class instead of business.
Changsha-Futian leg has 10 trains daily, with trip times 3:04 to 3:42. Departing Changsha 7:50 to 20:26, arriving Futian 11:32 to 23:47. 2nd class 397 yuan, 1st class 612 yuan, business class 1210 yuan. Some of the 10 trains have VIP class instead of business, some have both.
OP makes no mention of Beijing. And if the goal is to end up in HK then it is better to take the train to Shenzhen north than to Futian. Shenzhen north has buses to HK and it is on the same subway line that the Futian checkpoint. Futian station requires some transfers.