Very interesting concept. I like the idea of a non-historical land mass to fight over. I once had a strategy game called Tactics II which was a battle that took place on a totally fabricated land mass. I used to have lots of fun with that game.
One small suggestion about your trains idea. Historicalboardgaming.com sells these small acrylic markers for rail lines, rail stations and even rail guns. I think those would be really good in a game like yours.