Model railroad layout

Part of an HO scale model railroad layout

In model railroading, a 'layout' is a diorama containing scale track for operating trains. The size of a layout varies, from small shelf-top designs to ones that fill entire rooms, basements, or whole buildings.

Attention to modeling details such as structures and scenery is common. Simple layouts are generally situated on a table, although other methods are used, including using a flush-sided door as a base. More permanent construction methods involve attaching benchwork framing to the walls of the room or building in which the layout is situated.

A poster made by Hornby advertising their model locomotives
Hornby Dublo poster as seen at Locomotion, Shildon



Track layout

Micro 'pizza layout' with 9 mm gauge track in 7 mm scale (09 scale)

An important aspect of any model railway is the layout of the track itself. Apart from the stations, there are four basic ways of arranging the track, and innumerable variations:

Common variations:

Different scales

A list of different gauges and their scales: Rail transport modelling scales#NMRA

In the UK, OO gauge is one of the most popular sizes as 1:76 is not 'too fiddly' nor too large to fit in one's room. Despite this, TT gauge (1:120 scale) is becoming increasingly popular because its tiny size enables anybody to have a larger layout in a smaller area. Still, the closer to life-size, the more detail can be added without using tweezers.

A comparison of different scales and their dimensions
A comparison of different scales and their dimensions
A complicated scale rule used for scale measurements when drawing plans or modeling.
A complicated scale rule used for scale measurements when drawing plans or modeling.

Some modelers use a scale ruler to ensure that something such as a brick wall is the correct height. For example, OO gauge uses the ratio 4 millimeters to one foot. So a 6 foot wall in reality would be 24 millimeters tall on the railway layout.

O Gauge

The first Gauge was known as O Gauge and was 1:43.5 in scale. Which is a quarter inch to the foot. The distance between the rails was 32 mm (1.26 inches). This size of train was good because of the level of detail one could add the diorama. But due to the space layouts took up and the expense of buying bigger trains, train manufacturers resolved to create a new scale known as Half O gauge or HO gauge.

HO Gauge

HO (standing for Half O) was a much more popular gauge because of its size and affordability. The gauge was 16.5mm between the rails. The scale was Half of O which was 1:87 but this at the time created another problem. The motors and wires inside the train itself were too big and were being crammed in the small spaces inside the trains which was difficult to do. Therefore Double O gauge was created (OO).

Double O Gauge (OO)

Double O (OO) used the same gauge as HO at 16.5mm between the rails but used a scale mismatch (1:76.2) which meant that the standard track didn't look quite right with the trains i.e. the sleepers are too close together to be prototypical. There are other options of course such as the Peco bullhead track which has prototypical sleeper spacing but obviously the gauge is still flawed in comparison to the scale.

How do the trains and tracks work?

A model train sitting on powered track next to a model hill diorama
Train sitting on powered track (OO gauge)
A DC power unit made by Hornby in the 1980s
A DC power unit made by Tri-ang in the 1950s
A DC power unit made by Hornby in the 2020s

You can read more about the other ways in which model trains were and are powered in this Wikipedia article

DC (Direct Current)

A model railway operates with the use of powered track (electricity) where a handheld transformer is used to alter the power of the track. A standard model train made by companies such as Hornby or Accurascale includes a motor driven by pickups that touch the metal wheels of the train thus carrying a current through the motor.

DCC (Digital Command Control)

Similar to DC, DCC still runs power through the track but instead of using just a simple current, DCC uses binary signals to 'call' for each train. On a DCC layout, each train has an address enabling you to choose which trains to power, when, what direction, which headlights to use and how fast. Instead of controlling the track, you now control the trains themselves. Each DCC train has a decoder which understands the signals sent by the handset and thus powers the train when called for.

Another feature of a DCC layout is that you can control other assets of your railway such as points, signals (if not already automated), sounds, and other electronic devices that you may want to add for an even more realistic experience.

DCC diagram of a layout

Station layout

Terminal station modeled on the East Texas Model Railroad Club HO-scale layout

There are three basic types of station, and sometimes combinations of these types:

Other factors which affect the track layout of a station include:

The simplest possible station for passengers consists of just a platform beside the track, with no points (US: switches) or sidings. Both terminal and through stations can be as simple as this; a junction requires at least one point.

Large manufactures

For a more general category of all companies relating to model railway or just simply 'models' visit this page.

A list of popular locomotive and rolling stock manufacturers
Locomotive

Manufacturer

Manufacturer First train released Present? Website
Hornby 1920 Yes
Tri-ang 1950 No. Merged with Hornby in 1964
Bachman 1968 Yes
Accurascale 2015 Yes. Bought Heljan in March 2026
Dapol 1983 Yes

Some other popular manufacturers include Rapido, Oxford rail, Arnold and Kato but these are slightly less known.

Hornby platform footbridge
Hornby platform footbridge
A model platform with a waiting room and a green train manufactured by Hornby
Hornby station waiting room

There are also some other big names in the model railway hobby but not for manufacturing trains. Although Hornby, Bachman and Dapol are also large scenic, building and accessory manufacturers, the below companies have been some of the most popular layout accessory companies in the world for over 20 years. The bold products indicate the company's most dominantly sold category.

A list of popular track and accessory manufacturers
Accessory

Manufacturer

Manufacturer Date founded Main product category Website
PECO 1946 Track, scale scenery, electrics, and rolling stock https://peco-uk.com/
Woodland scenics 1975 Scale landscaping materials, 1:87 scale (HO gauge) cars and model figures https://woodlandscenics.com
Digitrax 1993 Digital Command Control and digital accessories https://www.digitrax.com/
Oxford diecast 1993 Diecast vehicles and trains https://www.oxforddiecast.co.uk/
Kadee 1946 Magnetic train couplings that function like real ones and some rolling stock https://kadee.com/

References

  1. Track Peco Code 100, Code 75, Bullhead, EM and P4 explained at Chadwick Model Railway | 66. Retrieved 2026-11-01.
    1. 1 2 3 Start at 1:40.
  2. ↑ "O scale", Wikipedia, 2026-10-07, retrieved 2026-11-01