The object of Mexican Train dominoes is to accumulate the lowest score by placing dominoes end to end. Subsequent dominoes must match in number to the previous domino, and the game starts with the double 12 domino in the center of the board, or table.
A game of Mexican Train dominoes uses the 91 dominoes of a double standard set. If there are four players, each player gets 15 dominoes, and five or six players get 12 dominoes each. The remaining dominoes go face-down in a pile known as the boneyard. From the double 12 domino in the center, each player starts a train by placing a domino with a 12 on it next to the double 12. During the first turn, a player may make as many moves as he can.
During the next turn, each player is allowed only one move. If the player cannot make a move, he draws a domino from the boneyard. If the player still cannot make a move, he places a penny on his train. Players are only allowed to make plays on their own train, on a train with a penny or on the Mexican Train, which is a train that any player has started that is separate from each player's train. The Mexican Train has a nickel on it. The game continues until one of the players runs out of dominoes, or until all trains have a penny on them. MastersGames.com has a complete set of rules for Mexican Train dominoes.