General
Players start with 4 cards and refresh their hand to 4 (or 5 in SFR) at the start and end of each round.
Each player begins the game with 4 cards in hand. At both the start and end of each round, players draw cards back up to a hand size of 4 (in the base Santa Fe game) or 5 (in Santa Fe Rails). Hand refresh is in addition to any card plays during the round.
Turn structure
Each round has two track-laying opportunities: TL1 and TL2.
Every round, a player has two track-laying turns: Track Lay 1 (TL1) and Track Lay 2 (TL2). By default, one segment may be laid per track lay. Multiplier cards (2x, 3x, 4-in-1) modify the number of segments that may be laid. The sequence each round is: play card(s), lay track TL1, lay track TL2.
Scoring
City cards score points equal to (number of city cards played) × (city value) × (number of distinct MRs/SLs connected to that city).
There are 66 City cards in the deck. When scored, a City card's value is calculated as: (count of City cards played for that city) × (the city's printed value) × (the number of distinct Major Railroads and/or Short Lines currently connected to that city). City cards have no special play restrictions beyond the standard card-play rules.
Special
When drawn, a Short Line card is immediately placed in front of the drawing player; that player draws a replacement card.
There are 4 Short Line cards. Short Line cards are unique: when a player draws a Short Line card, it is immediately placed face-up in front of that player (it does not go into the hand) and the player draws a replacement card to maintain hand size. Once a player holds a Short Line, they may use it to build the corresponding Short Line's track. Short Line track may always branch. Short Lines do not score the first-connection bonus ($2) for their own base city. No play restriction symbol (∅) means it can be played at any time; the draw note (⇓) means draw a replacement upon drawing it.
Building
Short Line track may always branch from any point.
When building track for a Short Line (using its Short Line card), the track may branch at any point — there is no restriction on branching for Short Lines, unlike Major Railroads which may have different branching rules.
Card play
The 2x card lets a player lay two segments per track lay, doubles all bonuses for the round, and (before TL2) may be removed from game to redraw any in-hand city cards.
The deck contains (n-1) copies of the 2x card, where n is the number of players (e.g., 3 cards in a 4-player game; counts are 3, 5, 7, or 9 depending on player count as listed). Effects: (1) The active player may lay two track segments per track lay (TL1 and TL2) this round. (2) All bonuses scored this round are doubled in value. (3) Before TL2, the player may optionally remove the 2x card from the game entirely to redraw any number of city cards currently held in hand. The 2x card is returned to the side of the board at end of round (↻, SFR only) and is removed from the game after use (✖).
Card play
The 3x card lets a player lay three segments per track lay, but no bonuses are scored this round.
There is 1 copy of the 3x card. Effects: (1) The active player may lay three track segments per track lay (TL1 and TL2) this round. (2) No bonuses of any kind are scored during this round. Play note: must be played in the turn it is drawn (⬇) and is returned to the side of the board at end of round (↻, SFR only). Draw note (➀): only one of the three special card types (3x, 4-in-1, Branch Line) may be drawn in a single round.
Card play
The 4-in-1 card lets a player lay 4 segments in one track lay and 0 in the other.
There is 1 copy of the 4-in-1 card. Effect: the player lays 4 track segments in one track lay (either TL1 or TL2, player's choice) and 0 segments in the other track lay this round. Play note: must be played in the turn it is drawn (⬇) and is returned to the side of the board at end of round (↻, SFR only). Draw note (➀): only one of the three special card types (3x, 4-in-1, Branch Line) may be drawn in a single round.