I highly recommend Train Simulator, when I owned it, I got rid of it quickly as I lost interest (Northeast Corridor not going north on Philadelphia, and me being terrible at operating those steam trains had something to do with it). Now though, I realized that it actually was a great game and I wish I still had it, especially with these new LIRR add-ons for it.
I would be patient though and wait for Train Simulator 2, which is supposed to have a large network of routes (which I hope include the LIRR, or Metro-North's Port Jervis line).