Changsha Railway Station questions

I'm confused: are there 2 railway stations in CS? I am taking a bus from Fenghuang and it takes me to the "CS Railway Station" but I want to jump on a G-train in that city to go to Shenzhen. Is it the same station or do I have to travel from that train station to another train station? If I miss the bus in Fenghuang that goes to the train station, I can take another bus that goes to a bus station in CS. I need to know how to get from that bus station to the train station for my G-Train. Thank you.