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SCALE & GAUGE EXPLAINATION
Gauge and Scale are the two most commonly mis-used
terms by model railroaders. Many folks state that they model in a
particular
gauge. But gauge is not correct term to use in that case,
and they should rather have stated that they model in a particular
scale.
Here's why :
SCALE |
SCALE refers to the proportion of the prototype to the model. ( See note below ) |
GAUGE |
GAUGE refers to the distance between the heads (tops) of the rail of the track. |
Using S scale for example which is 1:64 the proportion
of the prototype, the "1" represents the prototype, and
the "64" represents the model, stating that the model is one sixty-fourth
the size of the prototype.
Though there are quite a few others, the following chart lists the most common scales that railroad enthusiasts model in :
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COMMON SCALES |
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SCALE |
OTHER DESIGNATION |
PROPORTION |
TRACK GAUGE |
M |
----- |
1:13.7 |
(45mm) ( See * note below chart ) |
F |
----- |
1:20.3 |
(45mm) ( See ** note below chart ) |
G |
"Goofy Gauge" |
1:22.5 |
(45mm) ( See *** note below chart ) |
I |
Gauge 1 or #1 Scale |
1:32 |
(45mm) |
O(17) |
----- |
1:45.2 |
? - 1.250" (31.8mm) |
O |
----- |
1:48 |
Standard - 1.250" (31.8mm) |
On30 |
O16.5, Oe or On2½ |
1:48 |
2' 6" Narrow Gauge - .?" (16.5mm) |
On3 |
----- |
1:48 |
3' Narrow Gauge - .750" (19.0mm) |
On2 |
----- |
1:48 |
2' Narrow Gauge - .500" (12.7mm) |
S |
3/16" Gauge |
1:64 |
Standard - .875" (22.2mm) |
Sn3 |
----- |
1:64 |
3' Narrow Gauge - .563" (14.3mm) |
OO |
----- |
1:76.2 |
Standard - .750" (19.0mm) |
HO |
----- |
1:87.1 |
Standard - .649" (16.5mm) |
HOn3 |
----- |
1:87.1 |
3' Narrow Gauge - .413" (10.5mm) |
HOn2 |
----- |
1:87.1 |
2' Narrow Gauge - .276" (7.01mm) |
TT |
"Table Top" |
1:120 |
Standard - .471" (12.0mm) |
TTn3 |
----- |
1:120 |
3' Narrow Gauge - .300" (7.62mm) |
N |
----- |
1:160 |
Standard - .353" (8.97mm) |
Nn3 |
----- |
1:160 |
3' Narrow Gauge - .520" (6.35mm) |
Z |
----- |
1:220 |
Standard - .257" (6.52mm) |
*** NOTE :
G scale is not a true scale. There are
at least three substantially different sizes of models calling themselves
"G Scale"
that operate on 45mm (I Scale) track. "G" is just a designation given
by L.G.B. to describe High Rail IIm standards
in Europe, which has (unfortunately) become accepted in the U.S. But
the 45mm track that "G" models operate on
is actually Standard Gauge track for "I" scale.
The three scales below all operate on 45 mm "I" gauge track |
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1:29 |
Standard gauge |
1:20.3 ** |
3 foot gauge |
1:13.7 * |
2 foot gauge |
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Regardless of what scale you are interested in modeling
in, below is an example of the
easiest method I have found for determining the size a model should be in
your scale.
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Figuring Scale |
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STEP |
DESCRIPTION |
EXAMPLE |
Step 1 |
Take ACTUAL measurement and convert it to inches. |
3' = 36" |
Step 2 |
Divide that measurement by the scale size you want. |
36" ÷ 64 (S scale) = 0.562" |
36" ÷ 87 (HO scale) = 0.413" |
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36" ÷ 48 (O scale) = 0.75" |
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36" ÷ 32 (I scale) = 1.125" |
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Step 3 |
OPTIONAL : If possible, convert the answer to a fraction. |
1.125" equals 1-1/8" |
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