Scale and Gauge, Wheel and Track Standards


Scale and gauge has always been a confusing issue in the model railway field this is even more so with the collectable items.

In the early days of model railways the majority of manufactured products were either clockwork or live steam. This by necessity meant that the models had to be a reasonable size to either feet a small boiler or clockwork mechanism of any significant ability This resulted in what we now know today as the large gauges ie  gauges 1, 2& 3 As manufacturing and technology improved a small gauge was introduced called gauge O as most people felt that it was the smallest practical size for model Railways.

The majority of collectables pre-war were in either gauge O  or gauge 1

Gauge O is today measured in the Metric system and equates to 32 mm between the inside edge of the running rails and gauge one is 45 mm. Gauge one is also used for garden railways especially steam-powered models.

Towards the end of the 1930s toy manufacturers started looking at a much wider market in smaller homes and the result was model railways approximately half the size of O gauge giving rise to HO & OO with a track gauge. Of 16.5 mm exactly half of the O gauge dimension hence the description HO .   

This Diagram shows the differences between the Scales /Gauges

OO was used by the British toy makers to denote that their models were of a slightly larger scale compared with the Continental models but still running on the same track gauge. The main reason was that British prototypes were considerably smaller than the Continental prototype and therefore harder to insert clockwork and small electric motors.The scale of the model does not equal the gauge. For example, a narrow gauge locomotive running on HO track is to a much bigger scale than a standard gauge locomotive. The most common products collected in the Hornby railway collectors association are to be found in gauge O and HO/OO .  The scale is either 1: 48 or 1:45 for O gauge and 1:89 or 1:72 for HO/OO Most of the O gauge products such as Hornby, Bassett-in Lowke, Leeds and Marklin were not exact scale models. selective compression, especially in passenger coaching stock, was very common.

In HO/OO closer approximation to the prototype was attempted. However, most passenger rolling stock manufactured before 1965 tended to be foreshortened to make it look more realistic on small tabletop layouts. The manufacturers generally were able to get away with this as most people rarely looked at pictures of real-life trains side on. Most photographs demonstrate the locomotive and train running at about 60° to the observer and passenger coaching stock always looks a lot shorter than it is in real life, this was to the manufacturers' advantage.

Another issue that people find confusing is the definition, of course, standard, and fine scale. This does not mean necessarily the models are particularly different. As a general rule this refers more to the track and weel standards than to the superstructure, however, most coarse scale locomotives and rolling stock tend to be less prototypical then fine scale. As the hobby developed, manufacturers such as Bassett-Lowke and Leeds tended to make both their rolling stock and track to a more prototypical appearance. This was a move away from heavy wheels with large flanges and tinplate track to fine and more prototypical rail and wheels. Along with this change more attention to the superstructure detail was taken and hence the greater fidelity to prototype appearance. With the introduction of the smaller scales Hornby Dublo, Marklin and others improved the look of both track, wheels and superstructure. In fact, some of the last products of the Meccano factory in Hornby Dublo still bear excellent comparison with some of the finest of the new products from Hornby, Bachman and others.