Landing in Tianjin on a cruise ship, trainer to Beijing for 3 days

Actually, you will be eligible for 144 hour visa free transit since 72 hour visa free transit has been replaced in Beijing by 144 hour visa free transit a couple of years ago. Anyway, to be completely certain about your eligibility, here is a couple of conditions your itinerary has to fulfill:

- Your cruise is not allowed to have its last port of call, immediately before Tianjin, in mainland China port
- Your flight out of Shanghai is not allowed to have any additional landing within mainland China and in the country where your cruise will have its last port of call, immediately before Tianjin

If your itinerary fulfills the above mentioned conditions, you are definitely eligible for 144 hour visa free transit and you don't need any kind of visa.