18GB: The Railways of Great Britain

1. Setting and map
1830 covers the northeastern USA. 18GB takes place in Great Britain, but should not be confused with 1822: it's a different design that combines elements of 1825 and 1860 with the classic base of 1830 and its descendants.

2. Companies grouped into two random tiers
In 1830 all companies are available from the start on equal terms. In 18GB, during game setup, the railway companies are randomly split into two tiers. Which companies end up in each tier varies from game to game, so the map develops differently each time it's played.

3. The number of companies scales with player count
In 1830 the number of available companies is fixed. In 18GB the number of railway companies in play scales with the number of players: with the 2-player scenarios the game is faster and simpler, while with more players both complexity and length grow.

4. You can own 100% of a 10-share company
In 1830 the individual ownership limit is 60%. In 18GB a player can buy up to 100% of the shares of a single 10-share company.

5. You can sell any number of shares, including the director's certificate
In 1830 the president's certificate is normally not freely sold on the market, but rather transferred. In 18GB a player can sell any number of their own shares on the open market, including the director's certificate, a flexibility that 1830 doesn't allow in the same way.

6. An unusual set of city tiles
18GB has its own mix of city tiles and associated upgrade rules that make it more demanding from a track-laying engineering standpoint than much of the 18xx family, including 1830.

7. Inheritance from 1825: more flexible company structure
Unlike 1830, where all companies share the same 10-share structure from the start, 18GB incorporates ideas from 1825 regarding flexibility in how companies develop and are structured throughout the game.

8. Inheritance from 1860: its own stock market dynamics
18GB also incorporates stock market dynamics inspired by 1860 (such as the ability to freely sell the director's certificate), moving away from 1830's more classic restrictions in this regard.

9. Scenarios explicitly designed for 2 players
Unlike 1830, which is at its best with 3 or more players, 18GB includes dedicated and balanced scenarios for just 2 players, with shorter and more direct games.

10. Variability between games
Thanks to the random split of companies into two tiers (point 2) and scaling with player count (point 3), 18GB offers replayability and setup variability superior to 1830's fixed map and companies.

18GB: The Railways of Great Britain — Schematic summary (vs 1830)

SETTING

• Great Britain — its own design, not to be confused with 1822
• Combines elements of 1825, 1860, and the 1830 base
• Number of companies scales with player count; includes specific 2-player scenarios

VARIABLE SETUP

• Companies randomly split into 2 tiers → different map every game

STOCK MARKET

• Can own up to 100% of a 10-share company (vs 60% in 1830)
• Can sell any number of shares, including the director's certificate, freely on the market

TILES

• Unusual set of city tiles, with more demanding upgrade rules than in 1830