Open Rails - Open Rails is an open source simulator that is designed to run Microsoft Train Simulator content.
OpenTTD - An open-source clone of the classic game ...
openBVE - openBVE is an open source train simulator
Micropolis - Micropolis is the open source version of SimCity Classic from Maxis, developed by Will Wright and Don Hopkins.
Microsoft Train Simulator - Microsoft Train Simulator was a commercial train simulator for Microsoft Windows.
Simutrans - Simutrans is an open-source transport simulator.