Copyright 2000 T. Sheil & A. Sheil All Rights Reserved


Scale and Gauge


Scale, Gauge and Off-Scale

These days, we take scale pretty much for granted. The past hundred years have seen the pervasive development of standardization among most miniature hobbies, from model railroading to military miniatures to collectible diecast automobiles. Today, there are a handful of "standard" scales for any given hobby.

What exactly is scale? SCALE is the size relationship of a model to the real world. Usually, it is expressed in fractions. Thus, a scale of 1/24 has dimensions that are a twenty-fourth the height, length, width and depth of its real-world counterpart. Another way of doing this is 1:24, or "one to twenty-four". That means that one foot (or inch or millimeter) of real measure equals twenty-four of the miniature. (In America, this is generally measured by the foot.)

Another way to express scale in America is by the scale foot. So it is that "quarter inch scale" means a scale in which 1/4 inch equals one real-world foot - in other words, 1/48. We sometimes here "half-inch scale" (1/12), "quarter inch scale" (1/48) and "three-sixteenths inch scale" (1/64th) used by hobbyists.

A measure popular among military miniature hobbyists is that of the height of an average figure in a particular scale. It originated in Europe. This is normally measured in millimeters. For instance, "54mm scale" refers to 1/32, where the height of an average standing soldier would be 54mm, or 2 1/4 inches tall. (On rare occasion, one may hear inch measurements rather than millimeters). Figure height was originated by people who collected the soldiers themselves, and those who used miniatures in war games. The dimensions of other things - scenery, buildings, vehicles, etc. - were incidental to those of the miniature soldier.

Fraction and scale foot measurements tell us that those using them are focused on the dimensions of objects and distances, whereas those whose main concern is a humanoid miniature rely on figure height measures.

The model railroading hobby used letters to describe scale. Widespread standardization among the various rail-scales allowed for use of a simple letter code. Originally, the code referred more to gauge - the distance between rails on a given piece of track - than to scale. Thus O gauge meant model trains that used track whose outside rails were 1 1/4 inch apart. It's no coincidence, then, that HO would mean "half-O", for purposes of gauge. As interest in scale accuracy grew among toy train fans, the letters came to represent a scale moreso than a track width. Thus, O scale is 1/48 - in other words, a train that uses track 1 1/4 inches apart would be 1/48 scale. Scale and track width soon were distinguished. The plain letter denotes a scale and its gauge, while other track gauges within that scale get special attention. For instance, "HON3" means HO scale, using a narrow gauge track. This track is 3 scale feet wide, as opposed to the normal four foot- eight inches of standard railroad gauge. The N tells us that this is narrow gauge. HON30 is different, meaning narrow gauge of 30 inches.  By the way, HON30 is the same track gauge as the smaller N scale! As trains went from toy to scale model, thus the letter code changed from gauge to scale.

Different hobbies have their own particular scales, and not all of them equate with one another. Standardization, common in model railroading, is not an absolute in other miniature hobbies. Keep in mind that other hobbies have a different focus. Military figures stress the human dimensions, for instance, as opposed to the scale of objects and distances in model railroading. Sometimes it is like the old saw about what came first: the chicken or the egg? In model railroading, objects - trains and track - came before miniature people. For toy soldier collectors, the people came before the objects.

Track Gauges by Scale

Gauge is the distance between the outer rails.  Scales listed below are based on a real-life gauge of 4 foot 8 inches.

Name of Scale Inches Millimeters Scale
Standard 2 1/8" 53mm
#1 - G 1 3/4" 45mm 1/32 - 1/29 (Narrow: 1/20.3, 1/22.5, 1/24)
O* 1 1/4" 31.8mm 1/48 (1/43.5 in UK)
S 7/8" 22.2mm 1/64
OO (US) 3/4" 19mm 1/76
HO 5/8" 16.5mm 1/87.1
TT 15/32" 12mm 1/120 (US)
N  (OOO) 3/8" 9mm 1/160
Z 1/4" 6.52mm 1/220
O-3/16 **(O27) 1 1/4" 31.8mm 1/64

* Obviously, in 1/48, real-life gauge would be 5 foot.  That anomaly is overlooked by most O gaugers

** The original O27 scale trains were 1/64 scale models running on O trucks and track.


The Scales and Their Adherents

Let's look at a wide range of popular scales, who uses them, and why. Normally, model railroaders fall back on their letter code to denote a scale. Miniature soldier hobbyists use the figure height, while builders of other types of models tend to rely on fractions. Model railroaders involved in the larger scales - S and higher - will also use the scale foot measure.

Fractions:

A general rule is that when fractions are used to denote scale, the accuracy of scale is reliable. Naturally, this is a generalization and does not bear on every maker or model.

1/6 scale refers to models where one real foot is represented by two inches. Thus, a six-foot figure would be twelve inches tall. 1/6 is used mainly by those involved in large flying models or large human miniatures.

1/12 is a scale where one foot is represented by one inch. Thus, the average miniature human is about six inches tall. Again, favored for large models.

1/18 scale is popular among collectors and builders of model automobiles.

1/20 and 1/20.3 are used by some American G/ #1 gauge makers for narrow gauge.

1/22.5 is G Scale, a German narrow-gauge version of #1 gauge.

1/24 is also popular with the model automobile hobby, and with slot car racers.  It is used by some G / #1 makers

1/29 is the scale of some locomotives using G gauge track. G varies - some use it for 1/29 scale. while others use a 1/32 dimension.

1/32 scale is popular among builders of model military vehicles and toy soldier collectors. It is also used by some slot car racers. 1/32 is the height of the "standard" toy soldier. It is the same as the 54mm - 2 1/4 inch scale used by miniature figure collectors.

1/35 is another scale for military model builders. Its human miniature figures stand 50 to 51mm tall.

1/40 is occasionally encountered among automobile and military vehicle models. The average height of a human figure in this scale is 45mm. Many recent toy soldier "clones" are 45mm tall.

1/43 is a scale used by diecast model car collectors. Some cars in this scale are sold as O gauge miniatures. Actually, the scale varied between pure 1/43 and 1/48.

1/48 is popular with model railroaders, model airplane hobbyists and some diecast car collectors. Also known as "quarter inch (1/4 inch) scale" or "O scale", it has a small following among military vehicle model collectors. The height of the average figure is 1 1/2 inches, or 40 mm. Among wargamers, there's a relatively small contingent who use 40mm figures.

1/50 is another diecast car scale. It is often marketed as O scale, and in fact scale accuracy of these cars can range from 1/45 to 1/48 to 1/50.

1/64 is popular among diecast car collectors and miniature war gamers; it is regaining its popularity among model railroaders as "S" scale. The height of the average person in 1/64 is 28.5mm, or about 1 1/8 tall.

1/60 is better known as the 30mm scale of military minuiatures. For many years, "30mm" was the major wargaming scale. 30mm scale was supplanted by the profusion of 25mm figures in the early 1970s. 30mm figures are often used for S scale scenery.

1/72 scale is popular among model airplane builders, small-scale military model makers and some wargamers. A 1/72 scale figure is 25mm, or 1 inch tall. The scale was originally the mainstay of model airplane buffs. It has no precise counterpart in model railroading.

1/76th scale was the mainstay of small-scale military model builders, and is the true scale of the kits made by Airfix, Matchbox, Fujimi, and a few others. It has been marketed as 1/72 since the late 80s, but this in incorrect. 1/76 is also OO scale, a European phenomenon which emerged in the 1930s but was overshadowed by HO and this fell into decline. It is sometimes called 20mm scale, because the average height of figures introduced by a major maker in the 1950s and early 1960s was that height. Actually, 20mm figures are HO scale! As you can see, 1/76 had its problems with accuracy across-the-board.

1/87 scale is the most popular scale, used by model railroaders, small-scale military modelers, wargamers, slot car racers and diecast car collectors. Known to the rail hobby as HO and by war gamers as 20mm, it has more support than any other scale. This is due almost entirely to the rail folks, who assiduously worked to standardize the scale back in the 1940s and 1950s.

1/90 is an obscure scale used by some Central European manufacturers of model military vehicles. Today, it is sold as HO

1/100 scale is an off-scale for model builders. 3mm scale, also known as 'English TT' or '3mm scale', technically uses a scale of 1/106.  Some round it down to 1/100.  Several companies make 1/100 scenery products for architectural use, and these are also used by 3mm Scalers.

1/120 is another model scale. The founder of TT, an American engineer, used 1/10 inch as a scale foot.  (Tenths of inches are used in American engineering.)  For model railroaders, it is known as TT, for Table Top. TT was originally meant to be the next smaller scale after HO. It never caught much of a following, although it was popular in Eastern Europe during the Soviet era.  (The model train makers in East Germany made TT.)

1/144 is a small scale used mainly by model airplane and model boat builders. Occasionally, 1/144 vehicles find their way onto N scale layouts. The off-scale is also employed for space ships and scale model rockets.

1/160 is very popular among model railroaders as N scale. Its small size and fine detail make it the scale of choice for folks who want huge railroads or who have limited space.

1/220 is the new Z scale, which is intended to be the smallest railroad scale. A European import, it has a small following in North America.

Scale foot:

Quarter Inch scale denotes O gauge and 1/48 scale

Three-sixteenths scale means 1/64, or S scale

3 inch scale actually denotes a scale where the average human figure is 3 inches, or 70mm tall.

2 1/4 inch scale is the same as 1/32 and 54mm scale, referring as it does to the height of the average human figure.

Millimeters:

While millimeter scale would seem accurate, the fact is that makers who use this measure of scale can vary. We have seen numerous cases of figures marketed as one size which are actually closer to the next higher - or lower- scale. That's not a problem for wargaming or some military modelers, but for model railroaders it can be a major annoyance!

120mm scale is used by miniature figure builders, and denotes --- scale. The average figure is almost 5 inches tall.

90mm scale is favored by miniature figure collectors because of its large size and greater detail. The average figure is almost 4 inches tall

70 and 75mm scale are for military figures, these being 3 inches tall.

60mm scale is a toy soldier scale, denoting plastic figures about 2 1/2 inches tall. It is rarely used for serious scale modeling. The 60mm figures were plastic toy soldiers designed between 1950 and 1975. Some are still being manufactured.

54mm scale is the standard toy soldier scale, being 1/32. It is also one of the scales used in G scale, the other being 1/29.

50mm / 52mm scale is 1/35, and is a popular size for military miniatures and plastic toy soldiers.

45mm is a popular size of current toy soldiers. It equals 1/40 scale.

40mm is actually 1/48 scale, or O. 40mm figures are made by Elastolin, Starlux and other European makers for use in wargames. (Civil War figures from these makers are popular for use in 1860 - 1870 era model railroads!)

35mm is an off-scale used by a rare few suppliers of wargame figures.

30mm scale was used in military miniatures. It was the major wargame scale until the field was overrun by makers of 25mm figures in the early 1970s. 30mm is 1/60 scale.

28mm scale is also 1/64, or S. It has recently emerged as a wargame scale.

25mm figures are exactly one inch tall, and are 1/72 scale. The most popular wargaming figures, the main scale for model airplanes.

20mm figures, sometimes mistakenly sold as 1/76 scale, are actually HO scale. Because HO has such wide support, they're often used by wargamers as well as model railroaders.

15mm scale figures are a relatively recent development, made for wargames. They can be used in TT and N scale layouts.

10mm figures are more the latest wargame scale, and can be used in N scale layouts.

Letter Codes

The letter codes used to denote scale for model railroaders have an additional benefit. Because model railroad scales are well -standardized, you will generally find that items sold as a particular scale are accurate in dimensions. The only exceptions are O27 and O semi-scale trains - toy trains where scale is not the main concern - and some older off-scales like TT and OO.

Standard Gauge: the original Lionel trains were massive, with 2 1/2 inch gauge tracks. They were toys, so scale gave way to other considerations. Standard gauge trains are very rare today.

G scale has recently emigrated from Europe, Used in garden railways, its scale ranges from 1/20 to 1/32. Major makers are Aristo-Craft, USA Trains, Bachmann and LGB. Not bad if you can run trains in the backyard, but too big for most indoor use.

O Gauge / Scale was introduced by Lionel as an alternative to Standard Gauge. Technically, it is 1/48 scale. In fact, many O gauge trains are "semi-scale", with some dimensions truncated to allow use on 31" diameter track.

O27 is a peculiar way of semi-scaling O gauge to fit a 27" diameter curve track. O27 trains are slightly smaller than O. Originally, Gilbert introduced the idea of a 3/16 S scale train running on O gauge trucks and track. The idea was picked up by Marx, who specialized in it, and by Lionel. Lionel later dropped the 3/16 idea, but retained the smaller scaling for O27 trains. If you're a scale modeler, it makes a difference. If not, you'll have no problem mixing O and O27 trains.

S scale, promoted heavily by the A.C. Gilbert company, is 1/64 scale. It was very popular up until the early 1960s, being the biggest competition to Lionel's O and O27 trains. S tends to be more accurate, insofar as scale. It is slowly regaining popularity in North America, as S offers opportunities for more detail than HO without the large size of O and O27.

OO is 1/76 scale. In some cases (common British practice today), OO and HO used the same track. OO was more popular during the 1930s, but was eventually eclipsed by the growing popularity and affordability of HO. A very small number of model railroaders continue to support the scale in the US.

HO is 1/87 scale. Favored by a small group of serious model railroaders in the 1930s, it was developed as a scale rather than just a gauge. The realm of craftsman kits and scratchbuilders, HO competed with OO as the small scale of the day. It won out, and by the late 1950s enjoyed a large following thanks to its smaller size and lower cost than comparable O and S scale trains. HO has the widest support, insofar as trains, accessories, scenery, etc.

TT (Table Top) is more properly 1/120 scale. It was intended to be small enough for those with limited space. Though it has a few followers today, and was the main scale in Warsaw Pact countries, TT has pretty much fallen by the wayside.  A small group of TT fans keeps the scale going in the US.

3mm Scale, called 'English TT' by some uses a scale foot of....3mm!  It is technically 1/106 scale, some claim it is 1/103, and many narrow it down to 1/100

N scale was imported from Europe in the late 1960s. It was not always "scale," as the manufacturing capabilities and materials available then didn't allow for perfect miniaturization. Sometimes the old N trains resembles a tiny version of "semi-scale." Time won out, and the quality of N improved drastically. Today, N trains are scale and have exquisite detail. Though intended for folks with limited space to devote to model railroading, N scale has become an institution of its own and is also enjoyed by folks who want massive model railroads, regardless of space.

Z scale is the newest European import, being 1/220 scale. The tiny size allows a more elaborate railroad in a smaller area. It has a small following in North America. The gauge is only 1/4" (6.5mm!)

O Gauge versus O Scale

Hi-rail, 2-rail, AC and DC

Though classic toy train makers like Lionel, K-Line and MTH manufacture both scale and semi-scale trains, they are considered to be O gauge rather than pure scale. Classic trains run on three-rail track. Let's face it, friends: does that track look like the rail one might see on a real railroad? Even the new scale-type track offered by Atlas doesn't look exactly real. Real railroads use two rails, not three. Besides, most O gauge rail has little resemblance to real rail in shape or dimensions.

Then there's the matter of curves. O gauge trains can make it around a 31 inch curve. Real trains use wider curves, and so something isn't scale here! Or is it?

Though the Lionel Heritage series and Kline Classic Scale are 1/48 models in every regard, and some require wider-radius curves, they're still running on 3-rail track. And they happen to use Alternating Current, or AC.

A different kind of O trains are Direct Current (DC) powered, two-rail trains. These trains require a lot more room for the wider curves, have different couplers and are more like enlarged HO trains than classic O gauge. They don't have all the nice operating accessories, neither. DC O scale has a small following among scale model railroad buffs who have the space and money for that kind of operation. (Toy train buffs call those fellows "rivet counters.")

The difference? Those of us who have three-rail, hi-rail O gauge have more fun.

Narrow Gauge???

In case you don't know about Narrow Gauge but were afraid to ask.... In the late 1800s, railroad gauge was standardized to 4 foot, 8 inches between rails. Some US railroads had a six foot gauge back then, and it made transfer from one railroad to the other a problem.

But some railroads had another problem altogether: limited space for a right-of-way. These include logging, mining, and mountain railroads whose routes took them through tight curves, up narrow mountain ledges and through difficult forests. The easiest way to deal with it was to have a narrower gauge track. A large part of the Denver and Rio Grande Railroad was narrow gauge, for instance, because of its routes through the Rocky Mountains and its mining operations. The distance between rails would be anywhere from two to three and a half feet.

In model railroading, there are folks who specialize in narrow gauge. They denote their specialty by first giving the actual scale, and then the track width. Thus, HON3 means HO scale (1/87) using a 3 foot gauge. By coincidence, HON3 gauge is the same as the gauge of N track! And ON3 (O gauge, narrow 3 foot gauge) is the same width as HO track. Thus some narrow gauge is like using larger trains on smaller track.

No, it isn't as simple as buying HON30 trucks for your trains, and then setting up N scale track to run them. Not if you want to be scale, that is! The ties on N track are okay for N scale, but would be too small for HO. Thus, you'd first have to replace the N ties with slightly thicker ones in order to have a true scale appearance. And that's just the beginning.

Why do people get into narrow gauge? They have many reasons, but a lot are the kind of folks who get a thrill in making some things on their own. They have to make or improvise parts, since narrow gauge doesn't have the same wide support as standard gauge. For that reason, narrow gauge layouts tend to be very individual, very unique, and they have a high degree of creativity. (I've never seen a narrow gauge model railroad that was dull.) If you enjoy making your own, you might want to look into narrow gauge. (If you ever need something made and you have a narrow guage fan around, you're in luck).

Scale Standardization: Is the Scale True to Scale?

Reprinted from The Army Men Homepage -(see Command Center)

One cannot make the assumption that every scale item is true to scale in every way.  Experienced modelers know that scale can be a matter of interpretation. One manufacturer's 1/35 might not be another's.  We've run across this many times.  Army men have rarely been paragons of perfect scale.  Even the cast metal miniatures tend to differ, with one company's 25mm figures resembling another's 30mm troops.  Therefore, this chart is far from perfect.  Some of the dimensions are based on the most common interpretation rather than pinpoint accuracy.

 The original figures from Airfix (Infantry, German Infantry, Cowboys, Indians, Civilians, Colour Guards, etc.) were closer in size to HO figures than the standard 25mm scale.  Starting in the late 60s, the Airfix small figures got larger.  This is but one example of "scale / not really scale."  The toy soldier and miniature hobby has not made great strides in standardizing scales, which is why different manufacturers and even individual kits can vary.

The model railroad hobby has done tremendous work in standardizing N, HO, S and O scale. Initially, these scales only denoted the "gauge," which  is the distance between the tracks.  As the hobby grew, it eventually developed an "establishment" which set to standardizing everything else in the years following World War II.  With the backing of large organizations such as the National Model Railroading Association, the popular scales were given a very tight set of standards, right down to millimeters per scale feet!  Less popular scales such as Standard, TableTop (TT) and OO had fallen through the cracks.  They were not given the intense degree of scale accuracy and standardization that had been showered on N, HO, S and O.  Indeed, because toy trains like Lionel and K-Line use the O track width but do not adhere strictly to 1/48 scale, they are commonly called "O gauge."  "O Scale" denotes trains which are a perfect 1/48 scale in all dimensions.

G Scale, a relative newcomer, was originally 1/22.5 narrow gauge using #1 gauge track.  In practice, G / #1 gauge is somewhere between 1/20 and 1/32 scale, depending mainly on the individual manufacturer.  The model railroad establishment has standardized G's track gauge and related dimensions, but not the precise scale.  The original gauge is the old #1 at 1 3/4 inches, or 45mm.  The 'official' scale, using #1 gauge as standard, is 1/32.  Some US makers use 1/29, while the narrow gaugers run between1/24 and 1/20.  LGB, who resurrecteded #1 as narrow gauge, denotes G as 1/22.5.  (For more information on G / #1, click here)

For years, hobbyists using the 1/72 - 1/76 scale have filled in the gaps with HO scenery and models (i.e. ROCO MiniTanks and Roskopf's 1/87 - 1/90 scale vehicles).  Model soldier scales have never been standardized, so as to allow across-the-board availability of  perfect scale scenery and accessories.  The same is true in larger scales.  For instance, it was common for diorama makers in the early 70s to mix 1/32 and 1/35 scale vehicles, troops and accessories.  I have seen 1/35 scale kits that are virtually indistinguishable in scale from 1/32 kits!

Our chart reflects this, insofar as those scales which do not have strict, regulated standards.  Only the N, HO, S and O railroad scales are strictly determined.  1/100, 1/120, 1/144, 1/76 - 1/72 and others tend to fluctuate.  In effect, one company's 1/144 is not another's.  Mininature soldier 30mm scale is not always perfect 1/64.  (It coule be anything from perfect 1/72 to perfect 1/60th!)  Keep that in mind as you use this chart.  At best, non-standardized railroad scales are an approximation rather than an absolute.

Note: MM = 1 Scale Ft means that so many millimeters in a given scale would equal one scale foot.
Scale MM =1 Scale Ft Millimeter Railroad Inch Scale Inch height
1/32 9 54mm G / #1 3/8 2 1/4
1/35 8 50mm G / #1 1/3 2
1/29 - 1/30 10 60mm G/#1 7/16 2 1/2
1/24 12 70 - 75mm G / #1 1/2 3
1/48 6.5 40mm O 1/4 1 1/2
1/60*** 5 30mm S
1/64 4.75 28mm (28.5mm) S 3/16 1 1/8
1/72 - 1/76 4 25mm OO 1/6 1
1/87 3.5 20mm HO 1/8 3/4
1/100 3 18mm TT (UK) 7/64 5/8
1/120 2.4 14mm TT 1/10 6/10
1/144 2.25 13mm 3/32 1/2
1/160 2 12mm N 1/16 7/16 - 1/2
1/220 1.38545 8.3127 Z .05454 .327 (1/3)
1/6 50 300mm 2 12
1/12 24 150mm 1 6
1/18 15 90 - 100mm 3/4 4

*** 30mm figures are often used with 1/64 scale trains.  According to most 3/16"scale O gaugers, 1/60 is the largest allowable tolerance for use with a scale railway.

 


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