Double-12 Variant Rules: Each round uses a specific engine starting from 12 down to 0.
Start trains with the engine number. After a double is played, the next player must cover it.
When you can't play, draw or pass to open your train to others. Mexican train can be started by anyone matching the engine.
Double on — must be covered
Your personal train - always playable when not blocked
Zoe's train - only playable when open
Alex's train - only playable when open
Sophia's train - only playable when open
Public train - anyone can start or play on it