Model Train Locomotive Scales

Model trains are identified by the term “scale” which is the relationship between its size and the size of an actual train.

In model railroading the most popular scales are O, HO, N, and Z scale. The photograph shows O, HO, and N scale locomotives next to soup can provides a feel for their actual sizes. The O scale locomotive (the largest) is an Atlantic class steam locomotive made by Lionel. The HO scale diesel in the middle is a Union Pacific EMD engine from Bachmann. The smallest of the three is the N scale Kato Santa Fe diesel locomotive.

Now let’s take a look at the different scale size model trains sets locomotives.

O Scale – 1:48

Marklin, a German toy manufacturer was the first to manufacture an O scale model train around 1900. The manufacture chose the 1/48th proportion because it was the scale they used for making doll houses. O scale is where 1/4 inch equals 1 foot. O scale model train was originally identified Zero Scale, because it was a step down in size from 1 scale. From the 1920s until after World War II the O scale trains dominated the model train market. But as model trains became more affordable the space required to set up layouts became a major consideration in the purchase of a model railroad train.

HO Scale 1:87.1

By far the most popular scale today worldwide is the HO size model railroad trains. HO scale is where 3.5mm equals 1 foot. HO stands for “Half O”. The model train industry states that HO is “approximately half O” because HO is in metrics and O scale is based on English units of measures.

S Scale – 1:64

The S scale model trains were first introduced by A.C. Gilbert as American Flyer products in 1939. S scale is where 3/16ths of an inch equals 1 foot. The American Flyer brand still exists as Lionel product line even though very few companies manufacture S scale trains today.

TT Scale – 1:120

The TT scale was invented in America after World War II. It is very popular in Russia, eastern Germany, and former Soviet Union countries. The 1/120th scale is usually used in engineering diagrams because the size allows 1 inch to equal 10 feet. The TT scale has not received an acceptance outside of eastern Europe even though it fills the niche between HO and N scale.

N Scale – 1:160

The “N” stands for nine millimeter. N scale is where 2mm is approximately 1 foot. N scale model train has become the second most popular scale around the world. N scale is selected by many model train hobbies as an alternative to HO scale because a more complex layouts can be built in the available space. Manufacturing and the painting
processes are able to produce N scale models with surprising levels of detail.

Z Scale – 1:220

Z scale was the smallest available scale in model railroading prior to 2008. Z scale has become very popular with apartment dwellers and those that are limited for layout space. Z scale is awkward mathematically, approximately 0.0545 inches to the foot. Today the Z scale is the fastest growing scale in model train sets. There are manufacturers that offer an entire track layouts with landscape, buildings, and a power supply in a briefcase. These are high end toys that are selling for around $1,000.

G Scale – 1:22.5

G scale which stands for “garden”, is the largest consumer scale. G scale is where 1 foot is approximately 1/2 inch. LGB introduced the G scale in 1968. Marklin now manufactures most of the G Scale trains. These large size G scale trains are frequently used outdoors and that is why it is sometimes referred to as the “Garden Scale”. Lionel currently makes an animated G scale Christmas set that will circle around the base of a Christmas tree.

OO Scale – 1:76.2

OO scale is where 4mm equals 1 foot. This metric scale is very popular in the United Kingdom. The British firm Hornby is the largest manufacturer of OO scale trains.

Filed under: Model Trains Sets

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