The 0.706% Challenge
Railroad! Solitaire
0.706%
Win rate
350B+
Simulations
Free
App Store
How it works
A game of alignment and chain reactions
52 cards are dealt one by one into a single row. Your success depends entirely on the relationship between the 1st and 4th cards from the right end of the row.
Rank match
Same rank — clear four
When the 1st and 4th cards from the right share the same rank — two Kings, two Fives — all four cards in that group are removed from the row.
Suit match
Same suit — clear two
When the 1st and 4th cards share the same suit — both Hearts, both Clubs — the two middle cards are removed. The outer cards remain.
The cascade. Every time cards are removed, the row collapses and new matches can form — triggering chain reactions that clear large sections at once. Win by clearing all 52 cards.
Features
What's in the app
- Simulation-verified win rate — 350+ billion games confirm the 0.706% expected win rate. Every game is numbered and tracked.
- Live probability stats — A real-time histogram shows your score distribution across every game you've played, compared to the expected curve.
- Desktop versions — macOS and Windows builds available for players who prefer a larger screen. Download for macOS or Windows.
- v2.0 in development — Bonus games, achievements, and expanded player choice. Coming soon.
Screenshots
