18NL

1. The same 1830 system, transplanted literally to the Netherlands
Unlike every other game in this catalogue, 18NL doesn't reinterpret 1830: its own rulebook opens by saying "in principle, the rules of 1830 are valid." It's a direct transplant of the map, companies and privates onto the Dutch railway network (Almelo-Salzbergen, Nederlandsche Centraal, De Veluwe...), without adding any new subsystem (no loans, no mergers, no incremental capitalization): every change is small and concrete.

2. A ninth company on top of 1830's eight
1830 has eight operating companies. 18NL adds a ninth, the Noord Friesche Lokaal (NFL), the smallest company in the game (only 2 starting station tokens, same as the ZHE and the NRS).

3. The NFL floats with a 30% president's certificate, not 20%
In 1830 a director's certificate is always worth 20%, for any company. In 18NL, private no. 6 comes bundled with a 30% Director's certificate of the NFL (instead of the usual 20%), and this private closes when the NFL buys its first train — the same pattern as 1830's B&O, but with a higher president's stake that breaks the standard.

4. Two "B&O-style" privates, not just one
In 1830 only the B&O is tied from the start to a company's president certificate. In 18NL this pattern is doubled: private no. 5 comes with a 20% Director's certificate of the HIS (closes when the HIS buys its first train) and private no. 6 with a 30% Director's certificate of the NFL (closes when the NFL buys its first train).

5. Privates that convert directly into company shares
Besides the two "B&O-style" privates, private no. 3 (70 Gulden) can be converted into a 10% share of De Veluwe (DV), and private no. 4 (110 Gulden) comes bundled with a 10% share of the Nederlandsche Centraal (NCS). None of 1830's six original privates does anything like this.

6. A private that pays no revenue at all, and cheapens the next one
Private no. 1 (20 Gulden) pays no dividend whatsoever (0 Gulden), and as a direct consequence private no. 2 starts 5 Gulden cheaper in the auction. 18NL's own rulebook explicitly describes this as "similar to the SV&N in 1830" — that is, it's not a new mechanic, but the same 1830 quirk recreated with new numbers.

7. Specific tiles with "X" and "Z" type cities that don't exist in 1830
18NL removes the "B" tiles, the "NY" tiles, and the two-small-city tiles from 1830's tile set, and adds its own types: large yellow towns with a wide curve (value 20), green "X"-type cities (value 50) replacing the yellow "X" cities at E6, G2 and H3, small green towns (value 20), brown "X"-type cities (value 70), and a brown "Z"-type city (value 70) replacing the green "Z" city at B15.

8. Extra trains to feed the ninth company
18NL adds one extra copy each of a type-4 train and a type-6 train to the pool, to supply the additional company (NFL) that doesn't exist in 1830. Even so, the total amount of money in the bank stays identical to 1830's.

9. Certificate limits adjusted to compensate for the ninth company
Since there's one more company than in 1830 (and therefore more certificates in play), 18NL raises the per-player certificate limit: +1 with more than 4 players and +2 with fewer than 5 players, compared to 1830's standard limits.

10. A very local hex interaction: private 2's free token on the NZO's starting hex
If the owner of private no. 2 uses its power (a free station token on a hex with a large town but no track) on hex H13 — the NZO's home hex — that token stays blocked there until the NZO itself lays its own home token. It's a private-to-specific-company interaction with no equivalent in 1830.

18NL — Schematic summary (vs 1830)

SETTING

• Direct transplant of 1830's system onto the Dutch railway network
• 18NL's own rulebook states that "in principle, the rules of 1830 are valid"
• No new subsystems (no loans, mergers, or incremental capitalization)

COMPANIES AND PRIVATES

• 9 operating companies (vs 8 in 1830); the NFL is the smallest, with only 2 station tokens
• NFL's president's certificate: 30% (not the usual 20%)
• Two "B&O-style" privates: private 5 with 20% Director's share of the HIS, private 6 with 30% Director's share of the NFL
• Private 3 convertible into 10% of the DV; private 4 comes with 10% of the NCS
• Private 1 pays no revenue and cheapens private 2 by 5 Gulden (the same quirk as 1830's SV&N)

TILES AND TRAINS

• Custom tiles with "X" and "Z" type cities (values 20/50/70) replacing 1830 pieces
• One extra copy each of a type-4 and type-6 train to feed the ninth company
• Total bank money: identical to 1830

GAME ADJUSTMENTS

• Certificate limit: +1 with more than 4 players, +2 with fewer than 5, compared to 1830
• Local interaction: private 2's free token on H13 (NZO's home) stays blocked there until the NZO places its own token