The Inglenook Layout & Shunting Puzzles

History

The Inglenook is a version of a classic British puzzle that was first named and created by Alan Wright for his model railway shunting puzzle layout "Inglenook Sidings". Alan Wright's initial use of the puzzle was published in the early 1950's where he had incorporated it into his first small layout "Wright Lines". It was on this layout that he first developed the shunting of a five wagon train with three other wagons from an oval of track into two short sidings. The Layout "Wright Lines" appeared in the Railway Modeller in 1958 and in Model Railway Enthusiast in February 1995.

Alan Wright later concentrated the design into the original "Inglenook Sidings" which was first exhibited by him at a model railway exhibition in Manchester in December 1978. The layout was an instant success and won an award the same year. An article on the second version of "Inglenook Sidings", built as a mirror image trackplan of the first (with the head shunt to the right), appeared in the Railway Modeller in December 1992. Photographs of the 1978 layout have also appeared in C.J. Freezer's Model Railway Manual (1994) and in Scale Model Trains in December 1984. There was also an article written by Alan Wright on the layouts in the May-June 1999 issue of Model Trains International.

It is widely believed that the design was based on the prototype of Kilham Sidings on the Alnwick-Cornhill branch (Coldstream branch) of the North Eastern Railway (NER). The layout was an instant success and won an award the same year.

Basic Design

The layout design in its most simple form is very basic, consisting of a mainline with a spur leading off at an angle, and the spur itself then diverges into two sidings. There are only two points used and in many examples the the mainline also ends just beyond its junction forming the third and longer siding. The shorter sidings each hold three wagons and the longer siding five wagons. It is also usual for the head shunt to be limited to the length of a shunter loco and three wagons.

Basic Inglenook Sidings Track Plan

Operation

Most Inglenook Sidings puzzles require a train to be composed, consisting of five specified wagons out of the eight wagons in the sidings, in a specified order. The length of the sidings and therefore the minimum space in which the layout can be constructed is governed by the length of the wagons and loco used. In the standard British operation, short wheelbase wagons are used. These are frequently the 16T mineral or 5-plank coal variety and require a standing space of some 85mm each. The loco used is frequently the Class 08 0-6-0 shunter or similar, which requires 125mm. The overall layout can be easily fitted within a small space of 1200mm x 300mm, as indeed was Alan Wright's original "Inglenook Sidings".

Setting up an Inglenook Sidings Puzzle

Of course if more modern stock is being used or European - American - Canadian rolling stock is selected then some adjustment needs to be made. This will lead to a larger overall layout. Over the years the basic 5-3-3 Inglenook Layout design has been adapted to suit other situations. One of these adaptions, to enable the layout to be accommodated in a smaller space and which has found favour with micro-layout designers, has been the cut down version having a 3-2-2 formation with a loco plus 2 wagon head shunt. This reduced format uses a total of 6 wagons with the objective of the shunting puzzle being to make up a four wagon train.

A further reduction would be to use only a selection of 3 from 5 wagons on the 3-2-2 format - a Micro Inglenook. Although this can still offer some operational challenge and can be fun to play, the strength and complexity of the shunting puzzle has been severely reduced.

Wagons Unique
Arrangements of wagons
Wagons in train Possible trains
8 40,320 5 6,720
6 720 4 360
5 120 3 60

The Rules

As with all puzzles there nees to be certain rules of play.

  • The main objective of the puzzle is to form a departing train made up of 5 of the unique 8 available wagons that are placed in a random order in sidings B and C.
  • This objective can be further complicated by the rule that this train must depart from siding B (5 wagon capacity) with the remaining wagons left in any order together in one of the other sidings, either B or C.
  • The sequence of the wagons behind the loco in this train is selected at random at the start of the play.
  • The capacity of the head shunt A and the siding must be strictly observed and under no circumstances exceeded. This rule is easily observed in the absolute space layout as to do so would foul the points. But it is possible that the design of the layout has been extended to become a component part of a larger layout track plan. On such adaptations it is important that the head shunt A holds at least the loco plus the number of wagons equal to the capacity of the shortest siding as if this is ignored there will be sequences that cannot be made up due to the inability to remove the last wagon in the long siding.

The random selection can be made by any convenient means. Typical examples have been the use of coloured counters representing each wagon being selected from a bag; a pack of wagonds detailing each wagon being selected from a pack; to even a computer program.

If you wish to practice solving the puzzle away from the layout then a virtual version is available in the form of "Riverside Yard" by Neil Machin (Internet Explorer 4.0 or higher required).

Resolving The Puzzle

Strategies available to solve the puzzle include simple "Trial and Error", or systematically based on certain "Best Practice". Given the potential number of starting positions and different trains available to be selected it is likely that as much help as possible will be welcome.

Movement places on an Inglenook Sidings Puzzle

The first thing to observe is that the loco is really not part of the puzzle, so it has been removed from the following images. In true game play style, we need to understand certain game truisms.

  1. There are a total of 14 possible places that can be occupied by a wagon. In resolving this puzzle it is very important to understand this, as these "empty" places can be as important as the "occupied" places.
  2. There are 8 different wagons, each occupying a single place.
  3. The end of the game is when 5 wagons are placed in a predefined connected sequence, usually together in Siding B.
  4. Optionally, as a more challenging end game, the remaining wagons must also be left in any random sequence in either siding C or D.
  5. The 3 remaining wagons can be considered as having no required sequence. This means that they are no longer considered as different to each other.
  6. These 3 remaining dumb wagons can end the game in any sidings B, C or D but must not be to the head shunt end A of the puzzle.
  7. A move is defined as a number of wagons (maximum 3) moved from a siding B, C or D to the head shunt and back to siding B, C or D.
  8. All wagons are considered coupled to adjacent wagons in each move of the puzzle.

Stage #1: In order to solve the puzzle, focus on the occupied slots that are not part of the target solution. You need to be able to move rolling stock around in order to successfully solve an Inglenook Sidings puzzle. It is important to get out of the way the wagons that are in the way.

Stage #2 Count backwards. Try to back up wagons to the buffer stops rather than to build up the string of wagons from the loco end. Then add the next appropriate wagon to that. If that is not possible, try doing the same thing with the next wagon backwatds in the desired sequence

Stage #3 Use the empty places part of the moves by using some of the wagons that are not part of the required configuration to gain room for shunting moves.

Simple Example Puzzle

This is a simplified example. The target solution is to compose a train (Loco-1-2-3-4-5) from the following yard occupancy.

inglenook start position

Stage #1: The starting yard illustrates this principle, as it is obvious to begin with, that none of the wagons required to be assembled in the train solution (1-2-3-4-5) are accessible. So, the surplus wagons (unwanted wagon) need to be moved out of the way first before anything else is done.

inglenook move 1

Other possible configurations may tempt you to start shuffling wagons into the required order straight away, but unless you really have enough free slots to move around, all unwanted wagons should be moved to positions where they do not block further moves.

inglenook move 2

Once the required wagons can be reached, it is important to have a clear strategy. Placing wagon 3 (wagon 3) in front of wagon 4 (wagon 4) will not really help unless the other wagons can be sorted round this formation.

Stage #2: Counting backwards, in this example, setting off wagon 5 (wagon 5) at the end of one siding and then adding wagon 4 (wagon 4). To achieve this, the positions of wagons 5 (wagon 5) and 4 (wagon 4) need to be swapped around first.

inglenook move 3 out

inglenook move 3 back

inglenook move 4 out

inglenook move 4 back

inglenook move 5 out

inglenook move 5 back

With wagons 4 (wagon 4) and 5 (wagon 5) now in their correct sequence, attention now turns to the remaining three wagons.

Stage #3 In this example, they have been placed in the most awkward positions by being exactly the wrong way round. This will require the maximum number of moves to get them in the correct sequence.

inglenook move 6 out

inglenook move 6 back

Make the empty spaces part of the move by coupling up to some of the wagons that are not part of the train configuration to make room for shunting moves.

inglenook move 7 out

inglenook move 7 back

inglenook move 8 out

inglenook move 8 back

inglenook move 9 out

inglenook move 9 back

inglenook move 10 out

inglenook move 10 back

You can now back on to wagon 1 (wagon 1), couple up, advance, back up to wagon 3 (wagon 3), couple up, and your train is ready to depart with all wagons in their correct sequence.

inglenook solved

Although this completes the puzzle, it leaves the yard in a mess with the unwanted wagons placed in different sidings. An added twist to the basic puzzle can be to add the requirement that the 3 unwanted wagons must be left together in one of the short sidings so that the scene is set to receive the new 5 wagon train into the long siding to start the puzzle anew. In this example, it is easily done by using wagons 1 (wagon 1) and 2 (wagon 2) to transfer one unwanted wagon at a time from siding B to siding D.