The Hyperloop is a concept created by Elon Musk, CEO of SpaceX and Tesla Motors. In essence, pods travel through almost-vaccum tubes at speeds of 700+ mph, and a national network would be constructed similarly to a metro network. I think this would be an awesome addition to the game, you could have different maps for all the continents.
That would be interesting! Be neat if the “trains” had much higher top speeds than normal so worked more like the shinkansen in the Osaka map.