24 hrs visa free transit

Hi :) I have a question regarding the 24 hrs visa free transit. I will land in Chongqing day 1, 16.15PM. There I will have a layover until day 2, 9.00AM then fly to Guangzhou and arrive day 2, 11.50 AM. Am I eligible for a 24 hrs visa free transit, if I book a train to Hong Kong from Guangzhou departing Guangzhou before 16.15 PM day 2, or I need to book flight into a 3rd country? Thanks a lot in advance.