Introduction
18XX is the generic term for a series of board games which recreate the building of railroads during the 19th century, since the individual games use particular years in the 19th century as their title (usually the date of the start of railway development in the area of the world they cover). 18XX games all have several common features:

The games are based on hex maps representing an area of the world in which railroads are to be built. 
Railroads are built by placing hex tiles depicting track onto the map. The track connects stations through which trains owned by the railroad companies run in order to earn revenue. 
The games proceed with a series of stock rounds during which players buy and sell shares in railroad companies. Each stock round is followed by one or more operating rounds during which railroads which have been invested in lay track, buy trains, and earn revenue. 
The aim of the game is to make money by investing in the most profitable railroads. 
Railroads can pay out money to investors or withhold the money (for further train purchase or track costs). This decision affects the company's share price. 
The games proceed in phases whereby more useful/expensive trains bring in more complex track and higher values. 

List of titles in the series

Commercially published games
1825 England, released 1995 (Unit 1), 2000 (Unit 2), 2004 (Unit 3), designed by Francis Tresham 
1826 France and Belgium, released 2000, designed by David G.D. Hecht 
1829 England, released 1974, designed by Francis Tresham, started the series 
1830 Northeastern United States, released 1986, designed by Francis Tresham and Bruce Shelley 
1835 Germany, released 1990, designed by Michael Meier-Bachl 
1853 India, released 1989, designed by Francis Tresham 
1856 Canada, released 1995, designed by Bill Dixon 
1860 Isle of Wight, released 2004, designed by Mike Hutton 
1870 Mississippi valley, USA, released 1995, designed by Bill Dixon 
Note: The above represent commercial releases of games that use the format. There are many other 18XX games released in limited editions, or in kit or downloadable form, by individual designers. For further information see Blackwater Station.


Heterodox implementations of the game system
Ur 1830BC A game about irrigation in Mesopotamia, released 2001, designed by Jeroen Doumen and Joris Wiersinga 
2038 Asteroid belt, released 1995, designed by James Hlavaty and Thomas Lehmann