OpenTTD - An open-source clone of the classic game ...
Open Rails - Open Rails is an open source simulator that is designed to run Microsoft Train Simulator content.
Simutrans - Simutrans is an open-source transport simulator.
openBVE - openBVE is an open source train simulator
Transport Tycoon Deluxe - Transport Tycoon Deluxe is a Business Simulation developed by Chris Sawyer and published by MicroProse.
Microsoft Train Simulator - Microsoft Train Simulator was a commercial train simulator for Microsoft Windows.