No need to download the full game of transport tycoon when you can use Openttd : A clone transport tycoon deluxe, for free!

OpenTTD is an excellent clone of Transport Tycoon Deluxe, a great game originally
written by Chris Sawyer from Microprose.

It attempts to copy the original transport tycoon as closely as possible while offering many more new features.

Transport tycoon deluxe background:
To begin building an awesome transportation empire, the player must create transportation routes, consisting of station modules near industries or towns, and in the case of trains or road vehicles, physical road routes. One transport route can utilize several different forms of transport, e.g. truck?ship?train. The player's company and the stations each have ratings that depend on the efficiency or speed of moving goods between tem. Higher ratings then attract more goods (and therefore captial) to the station.