Railroad Empire is a Google Maps based game for Facebook. The game uses Google Map as the background for a railroad manager simulation game.
In the game you can buy and sell stations, buy trains, schedule your trains to stop at your stations, research improvements to your railroad company and manage your budget.
The stations and rail lines that you own are displayed on a Google Map. If you click on your station map markers you can then manage your stations and your trains.
That's enough for now - I need to get back to extending my Railroad Empire from San Francisco to LA.