Singapore Passport - Need China Visa when entering from HK?

As I know, Singapore passport holder can enjoy a 15 days visa free stay in mainland. The immigration check for the trip to HK is also at West Kowloon Station, after your arrival. You will go through both HK and Mainland passport control in same floor and then you can leave the station.

Would you know if I leave Guangzchou and take the normal slow train to HUnghom, is the immigration for China over at the Guangzchou East Station and the HK one is in Hunghom? How much is the taxi fare between Guanzchou South and the Guangzchou East stations cost and duration of travel?

I am thinking of going into China viua bullet train and leaving on the slow train within the same day.

Thanks Benson for earlier reply.

If you take the slow Z type, the immigration will be at GZ East Station and Hung Hom station. The transfer between South and East Station is about 1 hour no matter by taxi or metro. The taxi fare may around CNY70 or 80.

Can someone advise if Bahamas citizens need visa for mainland or Hong Kong?