Inglenook Sidings: the Shunting Puzzle, Rules, Variations and Maths

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Inglenook Sidings is a shunting puzzle on a tiny model railway: eight wagons stand in three sidings that hold five, three and three wagons, and you must make up a train of five of them, in an order drawn at random, using a headshunt that holds only the locomotive and three wagons. It was devised by Alan Wright, fits on a shelf, and is far harder than it looks.

The Inglenook track plan

The classic Inglenook has one set of points leading to a second, so that a single headshunt (yard lead) fans out into three sidings. The capacities are what make the puzzle, so they are fixed:

• Headshunt: the locomotive and three wagons.
• Siding 1: five wagons. This is where the train is made up.
• Sidings 2 and 3: three wagons each.

That gives 14 places for vehicles and eight wagons, so six places are always empty. The empty places are your working room, and there is never quite enough of it.

The rules of the Inglenook shunting puzzle

The task, in the words of the usual description, is to “form a train of 5 wagons selected at random of a specific order from the 8 wagons” (Wikipedia, Inglenook Sidings). Adrian Wymann’s long-running shunting puzzle site puts it the same way: the five wagons are selected at random, and the train must be made up in the order in which they were selected.

1. The start: the eight wagons are placed at random in the three sidings. The locomotive stands alone on the headshunt.
2. The train: five of the eight wagons are drawn at random, one after another. Alan Wright drew coloured tokens from a mug, which he called the “Tiddlywink Computer” (Wymann). Playing cards, numbered slips from a hat or a random-number app do the same job.
3. The goal: the five wagons stand in siding 1 in the order drawn, and the locomotive has let go of them.
4. Only the locomotive moves wagons. No “hand of God”, no pushing wagons by hand.

Clubs and players add a few house rules that follow from real railway practice. They are not part of the bare definition, so agree them before you start. The common ones are:

• wagons couple when the locomotive or another wagon touches them, and are uncoupled by hand (the uncoupling itself is free);
• no wagon may be left standing on the points;
• points may not be changed under a vehicle;
• the headshunt limit is real: with a fourth wagon on, the train would foul the points, so it can only go back where it came from.

How you score is up to you. Some count every drive of the locomotive; some count only how often the locomotive goes into a siding; some just play for the satisfaction of a clean shunt. Our online version counts every drive as one move.

How to play, step by step

1. Set out the wagons. Number or name the eight wagons and place them at random in sidings 1, 2 and 3, no more than five, three and three.
2. Draw the train. Draw five wagons at random and write them down in the order drawn. The first one drawn goes next to the buffer stop of siding 1 or next to the points, as you agree beforehand; our version reads the train from the points.
3. Read the board before you move. Find the wagon that has to go deepest into siding 1 first, and see what is in front of it.
4. Clear the way. Move the wagons that block it into the sidings where they will not block the next wagon, keeping the headshunt limit of three wagons in mind.
5. Build the train from the far end. Place the deepest wagon of the train first, then the next, and so on, so that you never have to dig a placed wagon out again.
6. Finish cleanly. When the five wagons stand in siding 1 in order, uncouple and draw the locomotive back. That is the puzzle solved; count your moves.

How hard is it? The maths of Inglenook Sidings

There are 8 × 7 × 6 × 5 × 4 = 6,720 possible trains (five wagons out of eight, in order). The eight wagons can stand in the sidings in 8! = 40,320 orders for each way of sharing them out, and there are 10 ways to share eight wagons over sidings of five, three and three. So there are 403,200 possible starting positions, and over 2.7 billion combinations of start and train.

Most of those are the same puzzle in disguise. What matters is only where the five train wagons stand and in which order; the three spare wagons are interchangeable. That leaves 67,200 genuinely different deals for any one train, and we solved every one of them.

How we counted. We used the classic abstraction: each siding is a stack read from the points, the locomotive carries at most three wagons, and one “visit” is a run into a siding and back out, leaving some wagons and taking the rest. A breadth-first search from the solved position finds the fewest visits for every deal. We report moves as drives of the locomotive, which is two per visit, minus one because the last visit ends inside siding 1. Our online puzzle uses the same solver and checks it against the board engine in its tests.

* Over every way of placing the five wagons. Carl’s own start always leaves siding 3 empty, which is one of those ways.

What the figures say:

• A typical deal needs about 23 moves even when played perfectly. Only about 7% of deals can be done in 15 moves or fewer, and 8% need 29 or more. The hardest 60 deals out of 67,200 need 33.
• The headshunt is the difficulty dial. One extra wagon of headshunt takes about four moves off the average and the worst deal down from 33 to 27. One wagon less, and the puzzle mostly breaks: seven deals in eight have no solution at all.
• Four deals in 67,200 are solved before you start, which is why a fair dealer, like ours, deals again when that happens.

Figures: our own calculation, 15 October 2026, under the rules and abstraction above. If your house rules differ (for example, if you count only visits), divide accordingly: visits = (moves + 1) ÷ 2.

Inglenook variations

The 5-3-3 plan is the standard, but the idea has been bent in many directions. These are the ones worth knowing:

The minimal Inglenook (3-2-2)

Carl Arendt found that “you can have fun shunting in a very small space by making the spurs hold as few as 3, 2 and 2 cars”, with a lead that holds two cars and the locomotive. Five wagons are scattered with siding 3 left empty, three are drawn, and the train is made up on siding 1 (Inglenook Designs). As the table shows, it is a gentler puzzle: about 14 moves on average, 23 at worst.

A longer headshunt

Carl suggests extending the headshunt if space allows, even as a removable piece at the end of the layout. It makes the puzzle friendlier, and the maths above shows by how much.

An arrival and departure track

To run it “like a real railroad yard”, Carl adds a hidden fourth track as the arrival and departure road for the rest of the world. Trains come in, are broken up and re-formed, and leave again.

Dual gauge Inglenooks

Carl’s Long Yard Industrial District puts the sidings in narrow gauge with a standard-gauge interchange track sharing a gantry crane, and a dual-gauge traverser off stage (Dual Gauge Layouts). See our dual gauge guide for how that track works.

A3-sized and narrow-gauge Inglenooks

The Gallery has an Inglenook drawn to fit an A3 sheet, 16.5 × 11.7 inches (A3 Sized Layouts), and Steve Bennett’s Ash Valley Farm Supplies, a classic Inglenook in O scale on 9 mm track, built in 12 × 36 inches (Inglenook Designs).

Different trains

Without changing the track you can change the job: draw the train as “any three of the brown wagons, in any order”, require a brake van at the end, or make up two trains at once. The more freedom in the train, the easier the puzzle.

Building an Inglenook layout

An Inglenook needs roughly the length of the locomotive plus eight wagons plus the points, which is why it fits on a shelf. Carl Arendt’s micro version of the Walkley/Inglenook plan takes up only three square feet, 9 × 48 inches (23 × 120 cm), and says the head shunt may need extending (Inglenook Designs).

• Measure your stock first. The sidings must hold exactly five, three and three of your wagons, not “about”. If they hold more, the puzzle gets easier; if they hold fewer, deals become impossible. Short wagons of one length make the capacities clean.
• Mark the clearance points. Put a small mark where a wagon would foul the points, so everyone knows when a siding is full.
• Use reliable couplings. Uncoupling over a magnet or with a pick is part of the fun; derailments are not. Couplings that work without the hand of God make the rules easy to keep.
• Keep the scenery to the back. The track is the game. Carl notes he has seen Inglenook shelves set anywhere “from Maine seaports to sleepy Midlands country terminals”.

For more plans see Carl Arendt’s Inglenook Designs, and for the wider family of small layouts our guide to small model railway layouts.

Where the Inglenook puzzle comes from

The puzzle was devised by Alan Wright (1928–2005), and its track is based on Kilham Sidings on the North Eastern Railway’s Alnwick–Cornhill branch (Wikipedia, Inglenook Sidings; Wymann, prototype examples). Carl Arendt traced the shelf-layout idea itself further back, to a portable layout built in England in 1926 by A. R. Walkley, which Wright revived in the 1980s as a switching game (Inglenook Designs). The puzzle reached a wide audience through the model railway press; Wikipedia cites the Australian Model Railway Association Journal of September–October 1985.

The Inglenook is one of two classic shunting puzzles. The other is John Allen’s Timesaver; our shunting puzzles guide compares the two.

Sources

1. Wikipedia, “Inglenook Sidings“, read 14 October 2026.
2. Adrian Wymann, “Inglenook Sidings: Rules & Operation” and “Prototype Examples“, wymann.info.
3. Carl Arendt, “Inglenook Designs“, Micro Layout Design Gallery, carendt.com.
4. Rex Little (ed.), Australian Model Railway Association Journal 34 (168), September–October 1985, pp. 156–157, as cited by Wikipedia.
5. Move counts: our own breadth-first search over every deal, 15 October 2026, as described above.