To begin, pull out the 12-12 if playing with a double-12 set (or the 9-9 if playing with a double-9 set) from the deck. This domino is called the "engine" and will be the centerpiece/starter for this game. Place the engine in the center of the table. Shuffle the remaining dominoes face down.

Number of tiles drawn: 2 players draw 12 tiles each; 3 players draw 11; 4 players draw 10; 5 players draw 12; 6 players draw 11; 7 players draw 10; and 8 players draw 9. Additional players can play by adjusting this numerical arrangement to fit.

Players draw their number of tiles with the remaining tiles set aside in "bonepiles", to be drawn as needed later in the game.

The players then organize the tiles in their hands in a playable progression beginning with the same number as the engine/centerpiece. The tile ends must match and form a line to be ready to play as your "personal train" when the game starts (example: 12-5, 5-7, 7-8, 8-11, 11-1, 1-9, and so on). When you are no longer able to line up your tiles in a matching series, the leftover tiles are considered your "extras" and will be used on the "Mexican Train" or on other players' "personal trains" during the game. If you do not draw a domino with an end that matches the engine/centerpiece tile, you can begin the line in your hand with any domino that will make up the longest line of end-matching tiles and the fewest "extras" possible.

To begin the game, choose a player at random to play first and then rotate the starters clockwise thereafter.
The first player must begin by either playing a matching tile from the "line-up" in his hand onto the engine/centerpiece nearest him, so beginning his "personal train", or by playing one of his "extra" dominoes to be the first of the Mexican Train. This Mexican Train is a line of "end-matching" dominoes that can run around the edge of the table or at some side space convenient to all players. The Mexican Train, one's own "personal train", and other player's "personal trains" (when markered) are the options that players can use to rid themselves of their tiles.

The Mexican Train begins with the first tile played by the player who chooses to play a domino from his "extras". It must be a domino whose end is the same as the engine/centerpiece. The train then grows as others play on it, but it can only be played on from the tail end, opposite the end that matches the engine's pips. The "personal trains" are spokes that grow outward from the engine/ centerpiece and appear as spokes on a hub. Wooden or plastic hubs are available to conveniently hold the engine and the "personal trains". The number of spokes or "personal trains" coming from the engine are determined by the number of players participating. Spokes can be squeezed in, if more than 8 players are involved, or if Double-15s are used.

It is always wise to start the Mexican Train as soon as possible as it gives more places to play. Try to play your "extra" tiles on the Mexican Train before you play on your "personal train".

After the starter has played one domino, the next player to the left does likewise by playing on the Mexican Train, beginning his own "personal train" leading off from the engine, or playing on another player's "personal train" if it has a marker on it. When a player cannot play on his own "personal train", or on the Mexican Train, or on another player's train, he must draw one tile and try to play it immediately. If unable to do so, the player passes and must put his marker out on the last tile in his "personal train" (even if it has not been started), marking it so that the last number to be matched shows clearly to everyone. Others can play indefinitely on that markered train until the "owner" plays on it and removes the marker. If a player plays a double during play, it is placed sideways and he must then play a second domino somewhere on the table. He does not necessarily need to play on the double he has just played. If he cannot play a second domino, he must draw another tile, then either play it or place his marker on his personal train.

After a double is played, all play is delayed until someone can make a play on this double. It doesn't matter if the next player can play somewhere else or not. He must play a tile on the double tile, even if he has to play a tile out of his train line-up in his hand (This is disrupting, but necessary). If players cannot play a tile on the double tile, they must draw once. If they are still unable to play a tile on the double, they pass and must place their marker on their "personal train" even if they had a matching tile to play on their train before the double was played. This means that once a tile has been played on the double tile, anyone can play on any "personal train" that has a marker on it, although this can really disrupt that train for the owner.

A player can play two doubles, as long as that player is able to play an additional tile from his hand (he is not allowed to draw) on one of those double tiles. This means that a player could play 3 tiles in one turn.

Play then proceeds to the left. When any player is left with just one tile in his hand, he must give notice to the other players by tapping his final tile on the table. This allows other players a chance to lower their score by ridding themselves of a higher numbered tile on their next turn.
General rules: If a player has a tile in his hand that will play, he must play that tile. He may not draw another.
If there are no more tiles in the bonepile, a player must pass if he does not hold a playable tile.
It is possible for a game to end by playing a double alone and no one being able to play on it.

The game is over when one player has dominoed (played his final tile) or when the game is blocked because no one holds a playable tile. Then, all players must count the number of pips on the tiles left in their hands (0, in the case of the player who has dominoed), and give that number - their score - to the scorekeeper.

As soon as the first round is completed, the next game begins by pulling out the 11-11, if playing with a double-12 set, or the 8-8, if playing with a double-9 set. The starter tile is placed in the middle of the table for the engine, and the rest of the deck is shuffled before drawing hands. All "personal trains" and the Mexican Train must be started with this same numbered new tile. Each new game thereafter should begin with the next-lowest double being played as the engine, with the 0-0 tile being the final engine for the last game.
The player with the lowest total score after all the games have been played is the winner.

5 to 8 players using the double-12 set (91 tiles). Adaptations can be easily made should your players/sets not exactly fit this guideline. Double-15 sets (136 tiles) can be used for even larger groups