72 Hours free transit to Guangzhou, Swedish Citizen ?

Dear Sir,
I am going to Hong Kong, I am a Swedish Citizen, I want to go by Train for 60 hours to Guangzhou, I do not have a Chinese visa, Can I get it on the train station in Hong Kong, get a 72h free transit and Going to Guangzhou ?

Question:
1). Can I get a 72 hours free transit.
2). Can I go from Hong Kong to Guangzhou and back
3). Can I travel by train ?
4). Where can get the entry permit, Hong Kong train station or Guangzhou train station ?