I also like trains.
I like the concept of the game. The only thing that felt a bit strange was the level up mini game. It felt a bit unrewarding that I needed to spend "money" on the upgrade but then also had to complete the mini game. Maybe allow the user to play the mini game for a discount or something before buying the item. That way it doesn't feel like you are “paying” twice for it (once with your money and once with the minigame).
Having the train act as a timer is a very smart idea. I like it.