Bullet Train G from Shanghai to Nanjing Checked Luggage

I have tried to find information on how to check luggage on the G bullet train and have gotten so many different responses. Exactly how do I do it? Is it baggage transportation services? Where are they in Hongqiao Railway Station? How early must I check the luggage prior to my departure? How will I know where to pick it up at the arrival station? What can I expect for fees? Bag size is 160cm, I heard bullet train restriction is 130cm. Thank you so much.