Train Simulator by Dovetail games has been around for many years, orginially known as railworks it is now known as Train Simulator 2016
Train Simulator provides everything you need to drive, create and collect. Drive a wide variety of trains on iconic routes around the world, and start your career as a train driver. Build and share fantastic routes, and download more created by other players. Build your dream train fleet with our growing range of add-ons.
The Steam workshop also has plenty of scenarios and routes you can download for free. There are a huge number of addons, engines, routes and scenariosto keep you interested in the simulator. However the main countries covered are England, Germany, USA and some routes for China and Austria.