

OpenTTD is an open source complete recreation of Transport Tycoon Deluxe, achieved by reverse engineering the original game. The game allows the player to save at any time, and multiple saves of a particular game at any point are possible. Playing the entire 100-year campaign takes about 40 hours. At this point, the year stays 2030 and never goes any higher, although the game can continue indefinitely. If the player remains in business until 2030, the game announces that they have won, allows them to post their name on the 'hall of fame' and then continues. These require a separate track system from railroads. In the game year 1999, monorails become available. Similarly, in the beginning there are only steam engines, but later diesel and electric engines are introduced. Later, they are replaced by red and green traffic-light signals. For example, railroad signals which allow more than one train to use a section of track are initially semaphores. The game features a progression of technology: in any particular year of the game generally only contemporary types of technology are available.

As the user plays the game and earns revenues, they have the choice of expanding service along existing routes, or expanding their transportation network.

The player starts out by borrowing money to finance construction of transport facilities, and is charged interest until the loan is repaid. The game begins in 1930, and ends in 2030.
