What is OpenTTD?
An open-source clone of the classic game Transport Tycoon Deluxe . It attempts to mimic the original game as closely as possible while extending it with new features.
Comments and Reviews
Said about OpenTTD as an alternative
Open source implementation of TTD
OpenTTD is more focused on transport and Citybound more general but I still get similar feelings when playing transport simulators and city building simulators. I'm sure that's not the case for everyone, but for me at least, these subgenres they are close enough to be alternatives to each other.
Its updated and has Multiplayer built right in and alot of players! even a reddit page!