24hr visa-free transit

Hi I am flying in from New Zealand to Guangzhou - Baiyun Airport and intend to leave for Hong Kong straightaway - am I allowed to use the bullet train instead of the slow train
I will fly back to Baiyun International airport after Hong Kong/Bangkok and will apply for the 144 hr transit visa then as I will stay in Guangzhou for 3 days before flying back to New Zealand Am sure this is all OK Please confirm