If it was real, it would be below ground, the train shaped Hovercraft would hang from the ceiling area and passengers would get on at the bottom of the train. The so called train would have two floors so people in good shape that don't like crowding could got upstairs.
I know I'm being judged all the time because of superficial outward appearances but the truth is I'm just a man that uses his imagination to create a little safe room, a place with some peace in this world filled with chaos.