I am by no mean an electrical engineer, yet out of curiosity (that's tied to a project I'm working on) let me pose to you this question:
Can a rail-gun model be used to propel a train car along a track? I've seen related designs on yt and I've yet to understand the difference, if there's any, between a rail gun and an "homopolar motor". my angle with this is that the shat of the wheels and the wheels are charged by the current passing through them.