Microsoft Train Simulator runs on windows machines, and lets you operate trains quite realistically! You can also build your own route, fictional or based on reality. There are also programs to build cars, locos, buildings, etc. If you check out train-sim.com, link below, there is a great deal of info, and the forums. They support a file library with 1000's of free downloads including a gorgeous model of the K-36's, Uintah's mallets and the Sumpter versions, etc. The model of Sumpter Valley RR that I'm building, will be there in a month or two.