Simutrans is a freeware and open-source transportation simulator. Your goal is to establish a successful transport company. Transport passengers, mail and goods by rail, road, ship, and even air. Interconnect districts, cities, public buildings, industries and tourist attractions by building a transport network you always dreamed of.
Pretty much the same game, except this one has some upgrades and some downgrades from OpenTTD (based on a quick google search)