Dominoes / Rules
How do you play Mexican Train dominoes?
Mexican Train is played with a double-twelve set of 91 tiles. The [12-12] goes in the centre as the engine. Each player builds their own train out from it toward their seat, and a shared train, the Mexican Train, is open to everyone. On your turn you play one matching tile on your own train, on the Mexican Train, or on any other player's train that carries a marker. If you cannot play, you draw one tile; if that does not fit either, you put a marker on your train and it is open to everyone until you play on it again. A double must be covered before play moves on. The round ends when someone plays their last tile or nobody can move. Everyone counts the pips left in their hand as penalty points, the next round starts on [11-11], and after thirteen rounds, ending on the double blank, the lowest total wins.
That much nearly every table agrees on. The details — how many tiles you get, how the first turn works, what happens when a double is left open — differ between written rule sets, and the two used below disagree on several of them.
The two rule sets compared here
There is no governing body for Mexican Train. The game is played mainly in the United States, and two written sources are worth naming:
- Pagat — John McLeod's rules page at pagat.com, the most careful general reference on domino games.
- The Parsons/Puremco rules — a rule sheet written by David Bauguess in 2007 (revised 2012), which says it is based on the "official" rules by Roy and Katie Parsons, ©1994, copyrighted by Puremco in 2005. Puremco makes double-twelve sets sold for this game.
Where this article says "pagat" or "Puremco-based", it means those two sources. Your own table may follow neither.
Setting up
Find the starting double. The Puremco-based sheet has you set it aside before shuffling, so all 90 other tiles are dealt from. Pagat has whoever holds it put it down, with players drawing until someone finds it — or, as an alternative, taking it out before the shuffle as well.
Then deal. This is the first place the sources part company:
| Players | Pagat (double-12) | Puremco-based (double-12) | Puremco-based (double-9) |
|---|---|---|---|
| 2 | 15 | 16 | 15 |
| 3 | 15 | 16 | 13 |
| 4 | 15 | 15 | 10 |
| 5 | 12 | 14 | — |
| 6 | 12 | 12 | — |
| 7 | 10 | 10 | — |
| 8 | 10 | 9 | — |
| 9–10 | 8 | — | — |
Each player needs one marker. Pagat's traditional kit is a penny per player and a nickel for the Mexican Train; sets sold for the game often include small plastic locomotives.
For a shorter game with two to four players, the Puremco-based sheet suggests a double-nine set, or taking the 36 tiles with a 10, 11 or 12 out of a double-twelve. That leaves exactly the 55 tiles of a double-nine.
How a turn works
Your personal train starts with a tile that matches the engine. In a [12-12] round, that means any of the twelve other tiles carrying a 12. Matching ends then follow outward, as in any line game.
On a normal turn you play one tile, on one of three places:
- your own train;
- the Mexican Train, which anyone may start with a tile matching the engine;
- another player's train, but only while it carries their marker.
If you hold a playable tile you must play it — both sources agree, and the Puremco-based sheet adds that strategy is no excuse. If you have nothing, draw one tile and play it if you can. If you still cannot, place your marker on your own train and your turn ends. When the boneyard is empty you simply pass and mark your train.
The marker comes off when you next play on your own train. Pagat lists variations: some tables lift it as soon as anyone plays on that train, others as soon as the owner plays anywhere.
The first turn
The sources differ most here.
- Pagat: on your first turn you may lay down as many tiles as you can as one unbroken train. Nobody may start the Mexican Train or play on someone else's train on the first turn. If you have nothing to start with, you put down a marker without drawing.
- Puremco-based: one tile per turn from the start. The starter may begin either their own train or the Mexican Train, and the starting player rotates clockwise each round. Pagat lists one-tile-from-the-start as a variation.
The difference is large. Under pagat's first turn, a hand with a long chain can put it all down at once. Under one-tile play, the same chain takes one turn per tile, while everyone else is playing too.
Doubles
Doubles are laid crossways. Playing one earns you another tile in the same turn, and both sources require the turn to end on something that is not a double. Past that, they differ:
- Pagat: the extra tile may go anywhere legal. If a double is left uncovered, the next player must cover it, even if it sits on a private train. If they cannot, even after drawing, they mark their train and the duty passes on. Several open doubles are covered in the order they were played.
- Puremco-based: while a double is open, every other train is closed to everyone, marked or not, until someone covers it. If you play several doubles in a row, the closing non-double can only go on the first of them, on the Mexican Train, or on an eligible train that does not end in a double. A double stops blocking play once all 13 tiles of its number are on the table, because nobody can cover it any more.
Pagat also notes that doubles in Mexican Train are not junctions. Once a tile sits on each side of one, that branch is done, unlike Chicken Foot, where a double sprouts three new lines.
Wikipedia's rule summary records a third version, in which the player who laid the double must cover it themselves. If your table argues about doubles, this is usually why.
Ending a round and scoring
A round ends when someone plays their last tile — a double counts, and no cover is needed — or when the boneyard is empty and nobody can play. The Puremco-based sheet asks you to tap your last tile on the table to warn the others.
Everyone else adds up the pips in their hand, and that is their score for the round; the player who went out scores zero. Thirteen rounds run from [12-12] down to [0-0], and the lowest total wins. Every number appears on 13 tiles, so each round has the same twelve tiles to start trains from.
Penalties hurt because the tiles are heavy. A double-twelve set holds 1,092 pips, 12 per tile on average. The [12-12] alone costs 24 if it is stuck in your hand, and a typical 15-tile deal in the first round carries about 178 pips.
Two common house rules change the scoring:
- Positive scoring (pagat variation): whoever goes out scores everyone else's pips, and the highest total wins.
- Penalty blanks: some tables charge 25 for each blank and 50 for the double blank. Wikipedia's article mentions this as an option. Pagat's Chicken Foot rules charge 50 for the double blank in that game.
For how pip scoring works across other domino games, see how a domino game is scored.
Odds worth knowing
You will not always be able to start. With twelve starter tiles among the 90 dealt from (engine set aside), the chance that a hand holds none of them is:
| Tiles in hand | No starter tile |
|---|---|
| 8 | 30.2% |
| 10 | 22.0% |
| 12 | 15.9% |
| 15 | 9.5% |
| 16 | 8.0% |
In a typical four-player, 15-tile game, about one hand in ten opens with a marker on it and no way to start. At ten players with eight tiles each, it is nearly one in three. On average a 15-tile hand holds two starter tiles. These are exact, computed over every possible hand.
Playing it well
The game rewards planning more than it looks.
Plan your train before the first play. Lay out the longest chain your hand makes from the engine number. The tiles that do not fit are your extras, and they are the ones you need to get rid of.
Play extras elsewhere first. Your own train is usually safe, because only you can play on it while it is unmarked. The Mexican Train and other players' marked trains are open to everyone, so they come and go. Put extras on them while you can, and keep your own chain as the reserve that guarantees you a move.
Shed heavy tiles before the round can end. Since leftover pips are the penalty, a [12-11] stuck in your hand costs 23 points. A [2-1] costs 3.
Use doubles inside your own chain. A double followed by its matching tile lets you play two tiles in one turn. Under the Puremco-based rule, an open double you leave on the Mexican Train can also freeze everyone else's play until it is covered.
Watch your marker. A train with a marker is the cheapest place for your opponents to unload. Once your train is marked, play on it at your first chance and take the marker off.
Before you sit down
Settle four questions: how many tiles each, whether the first turn lets you play a whole train, who must cover an open double and whether it freezes the other trains, and whether blanks carry a penalty. Those four cover most of the arguments in this game. For how Mexican Train compares to block, draw and All Fives, see the main domino games and how they differ. For what to buy, see which domino set to own.