Modelling in 7mm scale
There are many reasons why people make models of railways and railway
equipment and there is a large range of differing scales and gauges in
use. Almost since the beginning of the hobby 'O' gauge has been a popular
gauge to work in. Historically 'O' gauge referred to a track gauge of
1 1/4" or 32mm but is now almost universally taken to mean models
built to a scale of 7mm to the foot or 1:43.54, usually rounded off to
1:43.5. Prototype can be of Standard, Broad or any of the narrow gauges
and all are catered for by the Gauge O Guild, the object of which, as
stated in the rules, is to advance railway
modelling in the scales and gauges associated with the designation O.
This introduction seeks to outline the main variants of track and wheelset
standards used by 7mm scale modellers at the present time and to help
the newcomer to choose the most appropriate for him or her to work in.
A scale of 1:43.5 makes models which are a good size and easily handled,
while it is relatively easy to apply and appreciate fine details. Locomotives
can be powered by electricity, either from the rails using a 2 rail system,
a third rail, overhead catenary or stud contact, or from rechargeable
batteries, or by other power sources such as clockwork, steam or even
miniature internal combustion engines. They can be controlled through
the track or by radio control. Wagons and carriages have a satisfying
weight which makes them behave in a very proto-typical fashion. Their
size also makes taking them on to an outdoor railway a pleasant way of
There are a number of standards that have become established in 7mm scale
This page taken fron an article by Ian Middleditch, a former member of the Guild's technical
committee, explains the differences between these standards. It covers
Coarse Scale, Fine Scale, ScaleSeven, Broad Gauge and Narrow Gauge. An
additional paragraph has been added explaing the more recent 0-MF (medium
fine) variant of Fine Scale.
You can find more on narrow gauge modelling at the website of the 7mm
Narrow Gauge Association and the ScaleSeven
Group publishes a full set of standards on its website.
The article is taken from the Guild's ever expanding Manual,
which is now published on line.
New members to the Guild can purchase all the material issued to date,
on CD or in hard copy form. See the sales page
for more details.
Standard Gauge Models
Models of Standard Gauge prototypes are by far the most popular amongst
modellers and have been so since the earliest days of model railways when
models bore little resemblance to the prototype. The relatively simple
construction methods used in making these toys, the need to run them on
the floor round sharp curves, powered by steam, clockwork, or electricity,
usually at totally unrealistic speeds, led to the adoption of oversize
wheel and track dimensions with very deep wheel flanges and extra wide
treads, to make road holding as reliable as conditions would permit.
As modelmaking techniques and expectations developed track dimensions
became closer to true scale and today a growing number of modellers work
to exact scale dimensions. There are now recognised standards that will
meet the needs of anyone desiring to follow railway modelling at a number
of different levels. However modellers do not always adopt the latest
developments but decide to work with what is established and they feel
comfortable with. This is particularly so for existing layouts, as it
is often very costly in both time and money to change one's collection
of models and equipment to a different standard. Newcomers to 7mm scale
should appreciate this and carefully consider which standard best meets
their particular requirements and aspirations.
Today there are three distinct British track and wheelset standards
in regular use. It is important to realise, however, that all three are
based on the same scale, 7mm/ft, and that much of the equipment, components
and kits on the market can be assembled to comply with any of the standards.
In particular, rail sections are no longer associated with particular
The standards apply only to the dimensions of track and wheelsets. They
are not related to the faithfulness of reproduction of a prototype nor
to the amount of detail incorporated in a model. There now follows a brief
description of each standard with an outline of its advantages and disadvantages.