Answer:
I come with a train and go with a train and the train doesn't need me but can't go without me.
I come without being fetched at night, hide away as soon as daylight strikes. Although I may look small, I am much mightier than what you can imagine. What am I?
I am the best thing that can happen after a stick hits a ball.
I'm a ruler with 12 agents. Half of them work in the darkness. Who am I?
I give people a huge fright, but at the end I'm sweet. I normally celebrate at night, when there's less heat. What am I?
A little house full of meat, no door to go in and eat.