Hello,144 hr Visa free Transit

I'm from California, US and planning an Asia cruise next year. My cruise from Royal Caribbean will depart from Tianjin (1st stop) and going to different areas in Asia.

My question is : If we plan to fly from San Francisco to Beijing two days in advance to visit the city then taking the train to Tianjin for the cruise , total time to stay in China is less than 4 days. With this plan, will we are eligible for 144 hr free Transit ?
Thank you very much for your help.