There are as many layout designs as there are layouts. Trying to put them into categories in any way runs into the difficulty that some layouts will fall into all, some, or none of them. With that warning in mind, we can now look at different types of layout and the features that may be found.

Generalising, there are three main types of layout, the oval, the end-to-end, and the out-and-back (Figure 1). Practically all layouts are one or a combination of these. In spite of that, a great variety can be achieved with these elements. Examples are noted below with their salient characteristics.


Figure 1. Basic layout types (a) oval (b) end to end (c) point to loop, or out and back.

This is the basic test track, offering continuous running. It can be elaborated with loops and spurs to termini, or developed by superimposing one circuit on another, linked by gradients, to become a doubled over figure of eight. Given sufficient space, it is suitable for modelling main line operation.

This layout connects two stations or one station and a fiddle yard where trains can be marshalled off-scene. It is popular for branch lines but requires a very large space to simulate realistically a main line with its long trains and intensive operation.

This configuration allows departure from a terminal and return direct to the terminal. A variant is to introduce a triangular junction to allow running round the loop before returning to the terminal. Because these configurations involve return running on the same track, this introduces some wiring complexities. Many layouts are elaborations on, or combinations of, these basic types. For example, an oval may have two spurs to separate terminus stations, allowing end to end operation between the stations and continuous running around the loop. Alternatively, the principal feature of an oval might be a junction station where a branch line leaves the main line for a terminus station. Such a layout gives end to end running along the branch and connection with main line trains at the junction.

A variation on the oval is the loop to loop or dogbone layout. This is basically an oval, but the two “straight” sides are brought together between the two loops. If the oval is single track, the two sides can give the appearance of double track, or if double track, the appearance of quadruple. The loops may be hidden under hills and may be placed one above the other to save space. It allows continuous running, and is a suitable arrangement for display layouts.

A layout may include provisions for storing trains “off-scene”. This is where trains can be marshalled ready to be dispatched to the more visible and operational parts of the layout. Such storage features are not intended to be prototypical and have no form of scenic treatment. Operationally, they represent the rest of the world to which the visible railway connects. Good access is necessary, unless they are designed from the outset to be worked remotely or automatically, so they will usually be very visible to the operators, but in exhibition layouts they will often be concealed from the audience.

A fiddle yard is a set of parallel tracks connected to the exit track by points. Commonly it is used at one end of an end-to-end line to receive and dispatch trains to the station at the other end. On an oval line, a fiddle yard is connected to the oval at both ends so that trains can come and go in both directions.


Fiddle yard (photo: John Wilcox).

A traverser is operationally similar to a fiddle yard. The difference is that the base to which the tracks are fixed can be moved sideways to connect any track to the exit track. It replaces the points used in a fiddle yard, and saves the length of baseboard required which may be important where space is limited. The traverser may simply be moved by hand, but a mechanical operating system can be used if the owner so desires.

In a more sophisticated form, a traverser may be able to rotate through 180° so that trains can be turned around without handling them.


A small traverser using commercial drawer slide units (photo: Peter Smith).

Here the tracks are laid in a fan-like fashion and aligned with the exit track by pivoting the board on which they are laid. The pivot point may be in the middle of the storage tracks or located towards the end further from the exit track. If the former, and if there is sufficient space, the sector plate can be rotated through 180° to turn the trains around. This requires considerable space and good quality mechanical design and construction to work effectively, and in O gauge the length of trains may be a significant limitation.


Sector plate (Chris Klein).

This differs from the previous features in that the storage tracks are not fixed, but each track is mounted on its own base, usually with sides to make a U-shaped container that holds a train or a locomotive. Handles are advisable to assist in moving the cassettes around. When receiving a train, an empty cassette is aligned with the connecting track, and when dispatching a train, the cassette containing the train is aligned with the connecting track. Since only one cassette at a time is in use, the baseboard space required is not much more than the size of the cassette. Other cassettes can be held off the board and put in place as required.

Some form of aligning or locking is required to hold cassettes in alignment when driving trains in and out, and an electrical feed to the track on the cassette is necessary. Separate cassettes for locomotives, which need turning, and trains, which do not, will make the job of marshalling considerably easier.

Cassette storage has the advantage of minimising the handling of the locomotives and rolling stock themselves. When not in use, cassettes may also double up as stock storage boxes.


Single road cassette storage, hidden behind scenery (John Medley).

A passing loop is necessary if two or more trains are to be run on the same track. On the prototype passing loops were also used to allow faster trains to overtake slower ones, and this can make an interesting modelling feature. Time spent working out likely operating patterns should indicate the need for features such as these.

At a terminus station, a run-round loop allows the locomotive of the incoming train to get to the other end of the train in order to pull it out again. This is usually achieved by a release point or crossover near the end of the platform road, leaving enough room for the locomotive beyond the point.


Run round.

These were essential features at stations, docks and industrial complexes for the shunting, storage and marshalling of trains, both goods and passenger. The modern railway relies on block trains which has eliminated most of the shunting and marshalling that was formerly done and most sidings at small stations have been removed. Sidings for storage and the routine cleaning and maintenance of trains are still required.

A headhunt is a line, usually running parallel to the main line, connected to sidings that allows trains to be shunted without fouling the main line. Headshunts were widely used on the prototype, and since model railway layouts are usually operated very intensively (even when the prototype was not), they are very desirable features.

Turntables were used to reverse the locomotive, and were found in locomotive yards, and often at terminus stations without an extensive yard. Even if the line was operated with tank engines designed to run in either direction, locomotive crews would often turn the locomotive if the opportunity arose. With the end of steam operation turntables fell out of use and few now remain.

In a few loco yards, a triangle or a reverse loops was also used for turning locomotives.

Written by the Technical Committee for the Gauge O Guild Manual. Rewritten and adapted for the GOGWiki by Nick Baines.