OpenTTD - An open-source clone of the classic game ...
Railroad Tycoon - Railroad Tycoon is a very first installment in the series of Railroad Tycoon that was released in 1990 developed by MPS Labs and published by MicroProse.
Transport Fever - Transport Fever is an Adventure-based, Management, Strategy, Economy, Sandbox, City-Building and Single-player video game developed by Urban Games and published by Gambitious Digital Entertainment.
TheoTown - A City simulation game with great nostalgic graphics.
Simutrans - Simutrans is an open-source transport simulator.
Train Valley - Drive forward the industrial revolution in a train tycoon game!