Mexican Train

Objective

Lowest score wins. Say that twice if you've played regular dominoes — this game runs the scoring backward.

Every round, you're racing to empty your hand first. Go out and that round costs you nothing at all; everyone still holding tiles adds up the pips on them and carries that total forward. Get stuck instead, and every pip left in your hand is a point against you when the round ends, whether you went out or not. A match plays a fixed number of rounds — four online, or 4, 8 or 13 if you're playing solo — and whoever's cumulative total is lowest when the last one closes wins the match, not any single round along the way.

That inversion is the one thing worth holding onto before anything else in this guide: heavy tiles are a liability, not an asset, and a hand you can't unload is actively costing you every round it sits there.

The Tiles

Playboard deals from a double-twelve set: 91 tiles in total, one for every combination of two numbers from 0 to 12, including each number paired with itself — more than three times the 28 tiles a double-six set gives you.

Each tile is split into two halves, and every half shows a pip count from blank (0) to twelve. A tile where both halves match, like 8-8, is a double; every other tile pairs two different numbers, such as 3-11. With numbers running all the way to twelve, a hand can hide some genuinely heavy tiles — a 12-11 alone is worth 23 pips against you if you're still holding it when someone else goes out, so learning to read a high pip face at a glance matters more here than it does in the smaller set.

Diagram: Reading a hand

Six tiles, dealt and fanned out. One of them — 8-8 — is a double: the same number on both halves.

Six tiles fresh off the deal, none of them touched yet. Reading a double-twelve hand is the same habit as reading a double-six one — just with a wider range of pip counts to scan for.

The Deal and the Engine

Everyone draws a hand before the round starts — 16 tiles each if it's just the two of you, 15 apiece with three or four at the table. Whatever's left goes face down as the boneyard, the pile you'll draw from once you're stuck.

Every round is built around one tile that never enters anyone's hand: the engine. It's always a double, and it sits at the centre of the table as the value every train — yours, everyone else's, and the communal Mexican — has to start from. Round 1 opens on double-twelve; each round after that drops the engine by one, so round 2 starts from double-eleven, round 3 from double-ten, and so on. However many rounds your match runs, the engine is always 13 - round, which is the whole reason a hand that leaned on high tiles in round 1 can find itself short of them by round 4.

Diagram: A fresh round

Round 3 has just been dealt. The engine shows double-ten at the centre, and every train at the table — including the Mexican — is still empty, waiting for someone to play against it.

Nothing has been played yet, so every train reads as empty and every one of them grows from the same number: the engine's own value, ten. Next round it'll be nine.

Starting Your Train

Before your train has a single tile on it, it's the only place you're allowed to play. Not the Mexican, not an opponent's train even if it happens to be open — just yours, and only with a tile that matches the engine. That restriction lifts the moment you've placed your first tile; until then, it's the one legal move on the table for you.

It catches new players off guard because the tile is rarely the problem — most hands hold something matching the engine. The mistake is reaching for the Mexican train, or an open train someone else started, before your own has a single domino on it. Get your train moving first; everything else opens up once it has.

Diagram: The only legal destination

Your train hasn't started. The engine reads nine, and two tiles in your hand — 9-3 and 9-7 — match it. Neither the Mexican train nor an opponent's train is an option yet, no matter what else is in your hand.

P1's train is already rolling, but that doesn't matter to P0 yet. With 9-7 selected, only P0's own row lights up as a destination — 9-3 would work exactly the same way, and 2-5 doesn't match the engine at all. Playable reads 2, out of a hand of 3.

Open and Closed Trains

Once your train has a tile on it, it's normally closed: yours to build, and nobody else may touch it. Every other started train at the table works the same way for its owner — closed to everyone but them, by default, for the whole round.

A train only becomes fair game for the rest of the table when it's marked open, and that happens exactly one way: its owner had a turn where they couldn't play at all and had to pass. The instant that happens, their train flips open and stays that way — visibly, with an OPEN marker on its row — until its owner plays a tile onto it themselves, which closes it straight back up. Nobody can open your train by asking, and you can't close someone else's by playing on it; only its own owner's tiles move that marker, in either direction.

Diagram: Reading the marker

Three trains, three states. P0's own train is closed — only P0 may play there. P1's carries the OPEN marker, so anyone at the table can add to it. P2's is closed, same as P0's, off-limits to everyone but P2.

3-9 fits P1's open train, and selecting it highlights exactly that row as the destination. 8-5 would fit P2's train by the numbers alone — P2's end is 8 — but P2's train is closed, so it isn't offered: Playable reads 3 here, not 4. The fourth tile, 6-1, still has a home on P0's own train.

The Mexican Train

The Mexican train belongs to no one and everyone at once. It carries no owner, no OPEN marker, and no closed state to wait out — anyone at the table may add to it on their turn, every turn, the instant their own train has started. It's the one destination that's never off-limits for that reason.

There's exactly one catch: the Mexican starts out just as empty as every personal train, and starting it works by the same rule as Starting Your Train — the first tile played onto it has to match the engine. Once that first tile is down, it's live for the rest of the round, and its open end simply becomes whatever the last tile played on it left behind.

Diagram: Opening the Mexican

P0's own train is already underway, so the Mexican is fair game too — but it hasn't been started yet, and its open end is still the engine's own value, 12. Only a tile carrying a 12 can begin it.

4-12 is the only tile in this hand carrying the engine's number, and selecting it highlights the Mexican row — the only train still waiting on its first tile. P1's train sits closed and untouched; it isn't a candidate for anything in this hand.

Doubles

Play a double and two things happen at once: you keep your turn, and the table freezes. Nothing is legal for you next except a tile carrying that same number, played back onto that exact train — not your own train by default, not the Mexican, specifically the train the double is sitting on, wherever that happens to be.

This is the rule beginners misread most, usually in one of two directions. First: the freeze applies to that one train and that one number, not to the whole board — a double sitting on the Mexican locks the Mexican to its value, but doesn't touch anyone's personal train. Second: it's on you, the player who played it, and only you. Nobody else at the table gets a turn, and nothing else you own is affected, until you either cover it or run out of tiles that could and have to draw. Can't cover it even after drawing? You pass instead — and passing opens your own train, exactly as it would with no double pending. See Drawing and Passing for exactly how that works.

Diagram: The table frozen on 6

P0 just played 6-6 onto their own train. Now nothing is legal for P0 except a tile carrying a 6, and it can only land back on that same train — P1's train and the Mexican sit untouched, frozen out of the decision entirely.

0-6 and 6-11 both carry the 6 the pending double demands, and either one highlights the same destination: P0's own train, where the double sits. 3-8 and 1-9 don't — Playable reads 2, not 4, and it stays P0's turn until one of those two is played.

Drawing and Passing

No legal play doesn't mean your turn is over. It means you draw one tile from the boneyard and check again — if that tile fits somewhere, play it immediately, same turn. If it doesn't, and the boneyard still has tiles in it, that's as far as you get: one draw per turn is the limit, not one attempt after another until something works.

Only once the boneyard is completely empty, or you've already taken your one draw and it didn't help, are you allowed to pass. And passing is never free: it opens your own train, right there, on the spot — the marker that makes it fair game for everyone at the table, covered in Open and Closed Trains. A stuck turn always costs you something, whether it's a tile from the boneyard or the shelter your own train was giving you.

Diagram: Nothing fits, draw

None of P0's four tiles match any of the three trains they can currently reach — their own, the Mexican, or P2's open train. The boneyard still has tiles left, so P0 draws instead of passing.

Playable reads 0 — P1's train is closed and off-limits, and nothing in hand matches P0's own end of 6, the Mexican's 2, or P2's open end of 3. Five tiles still sit in the boneyard, so this turn draws rather than passes.

Scoring

A round ends one of two ways, and only one of them is free.

Go out — play your very last tile — and the round costs you zero, no matter what you were holding a turn earlier. Everyone else at the table adds up the pips left in their own hand and carries that total forward; there's no tally of what the winner "collects" the way there is in regular dominoes, because here the winner simply isn't charged. If nobody can go out and the boneyard runs dry with everyone still stuck, the round is blocked instead — every hand still counts its own pips, including the lightest one at the table, and the round simply ends where it stands.

Either way, the pips go onto a running match total, and lower stays better round after round. A match that runs four rounds online — or 4, 8, or 13 solo — finishes with whoever's total is lowest across all of them declared the winner, not whoever won the most individual rounds.

Diagram: One tile left

P0 has a single domino left: 4-4. It matches their own train's end, and playing it empties their hand — this round costs P0 nothing at all, while P1 still has to count every pip they're holding.

One tile, one legal destination — P0's own train, still open at 4. The instant this domino lands, P0's hand is empty and this round scores zero for them; P1's hand, whatever it's still holding, scores every pip of it.

Strategy

Count every live end you can actually reach, not just your own. With a full table, that's your train, the Mexican, and however many opponents' trains happen to be open at the moment — four or five numbers in play at once instead of the two a single shared line gives you in regular dominoes. Before you commit a tile, check whether it fits more than one of them; a tile that only ever fits one place is a tile you have no real choice about, so play the flexible ones first and save single-destination tiles for when you're actually stuck.

Unload doubles early rather than late. They're heavier on average, they demand an immediate follow-up the moment you play them, and holding one too long means the train you'd need to satisfy it on may drift away from that number entirely. Watch the boneyard the same way you'd watch it in any domino game, too — once it runs dry, a stuck turn stops costing a draw and starts costing you your train's shelter instead, since passing with nothing left to take is what opens it to the whole table.

Diagram: Four live ends, one choice

P0's own train, the Mexican, and two opponents' open trains are all reachable right now — four different numbers in play. One tile in hand, 5-8, fits two of them at once.

5-8 fits P0's own end of 5 and P1's open end of 8 at once — selecting it highlights both rows as candidates, and which one to pick is a real decision. 1-9 and 3-4 each fit exactly one place; 6-12 only matches P3's train, which hasn't opened yet, so it sits unplayable. With the boneyard down to 2, that shelter won't last much longer either way.