18xx

1825

• BoardGameGeek.com links: 1825 Unit 1, Geeklist: The Complete 1825
• Rules for '1825: The Great Game of Railways' [PDF, 240KB]
• Rules for '1825' Regional Kit: R1.1: Wales

1870

• Rules for '1870: The Trans-Mississippi' [PDF, 309KB | Open Office, 48.1KB]. These rules are literal transcriptions from the rules as posted by the game's designer Bill Dixon.

18EZ

The rules for '18EZ':

• Level 1 [PDF, 4.34 MB]
• Level 2 [PDF, 6.20 MB]
• Level 3 [PDF, 7.12 MB]