Open Rails - Open Rails is an open source simulator that is designed to run Microsoft Train Simulator content.
Trainz Simulator - Trainz Simulator is a commercial train simulator from Australia.
The Count of Monster Disco - The Count of Monster Disco is a Single-player Simulation developed by Skyhook Games and published by Dovetail Games.
openBVE - openBVE is an open source train simulator
Hmmsim Metro - Line 1, the most complicated subway in Seoul, is now coming in PC version. You can feel high immersion with the graphics that realize the actual Seoul scenery, the train driving sound, and the realistic train driving system.
Tiny Rails - Tiny Rails is an Adventure-based Single-player Simulation by Tiny Titan Studios.