21Moon

1. Setting: lunar mining in the year 2117
1830 covers the northeastern US in the 19th century. 21Moon moves the same game skeleton into the future: companies don't transport passengers or classic goods, but instead mine critical minerals on the lunar surface during the year 2117.

2. Temporary permits instead of permanent companies
In 1830 a company, once founded, lasts the whole game. In 21Moon, up to 7 corporations operate with temporary mining permits that last only 11 months (represented as 11 operating rounds in total), before a cargo rocket returns to Earth with the refined products.

3. End of game by calendar, not by bank or by trains
In 1830 the game ends when the bank runs out. In 21Moon the end is set by a strict deadline of 11 operating rounds in total, so there's no "dead queue" of passive turns waiting for something to happen: the game always closes at the same point on the calendar.

4. Hex value depends on minerals, which change with each tile
In 1830 a hex's value comes from the city it contains and doesn't change in nature. In 21Moon, the minerals present determine the hex's value, just like cities in classic 18xx games, but with a twist: when the tile changes (when it's upgraded), the mineral's value also changes, and depending on the mineral type, that change can be upward or downward.

5. Trains (transports) with their own progression: T2 to T6 and then T10
In 1830 trains follow a well-known 2-3-4-5-6-D progression. In 21Moon the "transports" go from T2 to T6 and jump straight to T10, and on top of that, T2s become obsolete when T5s appear (not T4s, as the intuitive equivalent would suggest) — a different obsolescence pace than you'd expect by analogy with 1830.

6. "Supply contract" bonus between colonies
A mechanic of its own with no equivalent in 1830: connecting the east-west exits between lunar colonies grants a "supply contract" bonus, important especially once the longer transports arrive and can reshuffle which routes are the most valuable.

7. Up to 7 active corporations
21Moon allows up to 7 simultaneous corporations mining the lunar surface, a figure that will depend on the number of players but can comfortably exceed what's usual in a standard 1830 game.

8. Rules engine recognizable from 1830 and 1846
Despite the science-fiction setting, players experienced in 18xx usually quickly recognize how 21Moon works, since its basic rules closely resemble those of 1830 and 1846: stock rounds, operating rounds, share and train purchases.

9. A more controlled, less passive endgame
Since the end is marked by a fixed number of rounds (point 3) rather than by emergent events such as a specific train showing up or the bank running out, 21Moon avoids the late-game stretches where some players just passively wait for the game to end — a situation that can indeed happen in 1830.

10. A pure science-fiction theme, with no precedent in 1830
While 1830 recreates the real history of the North American railway boom, 21Moon invents a near future of lunar resource exploitation, with no direct historical basis at all.

21Moon: The Race to Exploit Space — Schematic summary (vs 1830)

SETTING

• Lunar mining, year 2117 — up to 7 corporations with temporary permits
• Fixed end of game: 11 operating rounds in total (not bank- or train-triggered)

MINERALS AND HEXES

• Hex value depends on the mineral, which changes (up or down) when the tile is upgraded

TRANSPORTS (TRAINS)

• Progression T2 → T6 → T10 (direct jump, no T7/T8/T9)
• T2s become obsolete with T5s, not T4s
• "Supply contract" bonus when connecting east-west colonies

RULES ENGINE

• Very recognizable for 1830/1846 players: stock + operating + train/share purchases