Train to Busan is a South Korean film depicting a zombie apocalypse outbreak that occurs while passengers are aboard a train to the Korean city, Busan. A man is taking his daughter to Busan so she can be with her mother.
Secondly, they are going to keep as many characters alive as possible because Americans don't like sad or thought-provoking endings; we all just want a happy ending. So the father, daughter, man and his pregnant wife, and maybe the baseball player and cheerleader will make it. I think the bum will die.
Thirdly, they will change a lot about how the zombies behave. While this movie's zombies are far from what I personally think a zombie is like, it still has its features and Hollywood will take all those and just make it a Walking Dead movie on a train. These zombies are stupid, they react to light and sound, they run (which I think is a stupid feature for zombies), and their transformation time varies between person.