Which Beijing train stations are closest to BJ Airport?

I think all the train stations in the city are far away from the airport.
The South Railway Station is about 40km away from the capital airport, but from the south railway station, the airport shuttle bus line 10 can take you to reach the airport directly.
The bus on the way takes about an hour.

Is the Airport shuttle busline 10 inside the BJ South Station? How frequent does Airport Shuttle Busline 10 run, and where do we get the ticket? I am sure there are taxi, and how much will it be between South station and BJ International Airport? Thanks.

No, it is in the North Square of the South Station and you can easily find them. Near the shuttle buses, there is a ticketing office, where you can get the ticket and then board the bus. The interval is 30min and during rush hours, it is 10min.

Well, the taxi fare for the whole journey shall be around CNY120.