When I testing the dead Rails public testing realize that some zombie not working so here is my idea:

Add selectbox in the inside the train or the top train this feature would help a lot but why? Here how it work:

When player1 awake zombie when player1 going to the inside train as you can see player1 is in the train with selectbox zombie will understand that you are in the selectbox train and eventually they climb up and kill the player1 due player1 is in the selectbox zone train

By the way selectbox is a invisible