The object of all Trains games is to be the first player to place all of their dominoes. Dominoes may be placed onto the player's train, onto the Mexican train if available, or on the trains of other players under special circumstances.
The game is generally played with 2 to 8 players, though a large enough domino set can support 16 players or more. A double-six set can be used by up to four players, but the following extended sets are generally recommended to allow a substantial starting hand and boneyard:
The game also requires:
Many sets of dominoes include a station and special train-shaped tokens for markers, and aftermarket Mexican Train kits with a station and tokens of varying visual appeal are available. However, the station piece is not strictly needed, and anything from coins to poker chips to even pieces of candy or slips of paper can be used as markers.
At the start of each round, the dominoes are placed face side down, shuffled, and drawn by players to form their hands. Players pick six of the face down dominos.
Any remaining dominoes are placed to one side, forming the boneyard.
Each player picks one additional domino and the player with the highest number of combined dots goes first. This player plays a double domino in the middle. If this player can't play, they must pick an additional domino and play passes to the person to the left (clockwise). The player with the required double opens the station by placing this double in the center as the "engine" then play continues to the left
Each person may only lay one domino per turn. If they are unable to, they must draw a domino from the boneyard. If they are able to lay that domino, they may do so immediately. Otherwise, their turn is over and play continues clockwise.
Note that a player does not have to play a domino even if they can. They can pass, and must draw a domino. However, this is rarely good strategy.
A train can be as long as the players can make it; it only ends when all dominoes that could match its endpoint have already been played. As a result, trains can become quite long, especially with an extended domino set. It is acceptable to "bend" the train 90° or 180° to keep the train on the playing surface, as long as it does not interfere with the endpoints of other trains.
When a player must draw a domino, they must mark their train as "public" by placing a marker on the first car of the train. An unmarked train is "private".
Players with "private" trains have the option to play on their own train or not, or playing a domino on any train currently marked "public". Players with "public" trains can only play on their own train (an alternative rule is that all players can play on any "public" train).
When a player with a "public" train adds a domino to it, it becomes "private" again and may not be played on except by the train's owner.
The Mexican Train is an additional train that anyone with a "private" train can play on as their turn. They can start the train (by playing a domino matching the engine) or add to the train. The Mexican Train cannot be started on a player's first turn.
There is only one Mexican Train. It is usually marked with a black marker if one is available, or left unmarked (it is generally easy to identify, because it is the only train not facing a player).
The player who played the double must take another turn and "cap" or "finish" the double. If they cannot go, they have to draw a domino.
If they do not "finish the double", the train becomes a "public" train (note that if the train is not their own train, their own train does not become "public").
After this player's turn, no other train can be added to by any player until someone "finishes the double". Play passes to the next player who can legally play on this train (if the train is theirs, or if they can legally play on "public" trains). If they cannot "finish the double", they must draw a domino, and if they cannot play it on the double, their own train becomes "public". Play continues like this until someone "finishes the double".
At the end of each round, the player going out receives 0 points, while all other players receive the sum of all pips (dots) on their dominoes. The person with the least amount of points after all rounds have been played is the winner. In the case of a tie, the person with the most 0-point rounds is the winner. (If this is still a tie, the person with the lowest round total other than 0 is the winner).
With 4, 6, or 8 players, the game can be played in teams of two, with partners sitting opposite each other. Rules are identical except that a player's train and his partner's train are considered one and the same (they will usually extend from opposite sides of the station), and thus a player can play on his own end or his partner's, and neither end becomes public until neither partner can play a tile. Scoring is also handled in pairs, with the player who went out scoring zero for his team (even though his partner will have dominoes remaining) and other teams summing their scores for a team score.