Railway modelling has long used a variety of scales and gauges to represent its models of real subjects. In most cases, gauge and scale are chosen together, so as to represent Stephenson standard gauge. By choosing a smaller gauge than this for a particular scale, the model represents a narrow-gauge example.[1][2]
Such gauge and scale combinations are of course used for the deliberate modelling of particular narrow-gauge subjects, where the choice of subject is behind the choice of combination. Narrow-gauge modelling has also become especially popular from the purely modelling aspects: it combines a conveniently visible large scale that is easier to work on, with a narrow model gauge that allows tighter radius curves and so fits layouts into smaller spaces. This has been a particular reason in Europe where, houses being generally smaller than in the US, there is rarely space for 0 gauge and even 00 gauge is restricted in the size of curves.
At times, particularly in the early days before the inertia of popular scales developed, modellers would choose seemingly random scales in order to model a particular prototype and its original gauge whilst using a readily available gauge.[3] As the range of commercial products increases, both for gauges and scales, it is easier to find a combination that is already supported and so there is less need to scratch-build everything.[1]
Naming
Naming of these gauge and scale combinations follows a few broad rules, but not always consistently. Some, such as G gauge and SM32 were defined from the outset as narrow-gauge scales and so have a single component to their name.
British
Many names, particularly those of British origin, such as O14 and 00-9 combine the name of the scale used with the physical measurement of the gauge, i.e. the 7mm to the foot scale from standard O gauge with a rail gauge of 14mm, giving a precise representation of 2 ft (610 mm) prototypes. As it is the scale that controls interoperability between models and also the manufacture of non-railway scenery etc., it is the scale rather than the gauge that takes the primary position in names.
European
MOROP, the European model railway standards organisation, issues standards documents called NEMs . NEM010 defines the main model railway gauges, including narrow gauges.[2] Unusually, unlike the British model railway trade, this recognised narrow-gauge modelling from the outset. This may be because of Europe's greater prototypical use of the larger narrow gauges for smaller branch lines.
NEM010 defines and names narrow gauges for all the supported scales although it takes a broad approach and groups the prototypes into 'nominal size' ranges or Nenngröße. It defines these prototype gauge ranges as:[2]
| Gauge | Description | NEM code letter | |
|---|---|---|---|
| 1,250–1,700 millimetres | 49–67 in | standard gauge | |
| 850–1,250 millimetres | 33–49 in | metre gauge | m |
| 650–850 millimetres | 26–33 in | narrow gauge | e |
| 400–650 millimetres | 16–26 in | industrial | i |
| Feldbahn | f | ||
| 300–400 millimetres | 12–16 in | park | p |
Names are of the form 'H0e gauge', comparable to 00-9, as 'narrow gauge in H0 scale'. Thus the scale and approximate prototype gauge are represented, with the model gauge used (9 mm for H0e gauge; 6.5 mm for H0f gauge) being implied.[2]
The scales used include the general European modelling range of Z, N, TT, H0, 0 and also the large model engineering gauges of I to X, including 3+1⁄2, 5, 7+1⁄4 and 10+1⁄4-inch gauge. As 00 is a particularly British scale, it is not included within this pan-European standard. However the predominantly US imperial-based S scale (1:64) does feature.
United States
US gauges are named as On30 or Sn3, composed of the scale, 'n' for narrow gauge and the dimensions of the prototype gauge being modelled. These are universally in imperial units rather than metric, but there is no consistency between using inches or feet. Both On42 and On2 are used, but when referring to the prototype gauge, e.g. On30 / On21⁄2, the gauge is usually given in inches.
Gauge and scale combinations
| Gauge | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 gauge | O gauge | Proto:48 | P4 Gauge | EM gauge | H0 / 00 gauge | JM gauge aka #13 | TT gauge | H0n3 | N gauge | Z gauge | ZZ gauge | T gauge | |||||||||||
| Scale | 45 mm | 33mm | 32 mm | 1.177" (circa 29.9mm) | 24.5mm | 0.875 inches (22.2 mm) | 21 mm | 0.75 inches (19 mm) | 18.83 mm | 18.2 mm | 16.5 mm | 14.3 mm | 14 mm | 13mm | 12.7 mm | 12 mm | 10.5 mm | 9 mm | 6.5 mm | 4.5 mm[4][2] | 3 mm | ||
| SE scale | 7/8" | 1:13.7 | SE[ng 1] 2 ft (610 mm)[5][6] | SE[ng 1] 18 in (457 mm) | |||||||||||||||||||
| 16 mm scale | 1:19 | SM45[ng 2] 2 ft 9 in (838 mm) | SM32[ng 2] 2 ft (610 mm)[7] | ||||||||||||||||||||
| F scale | 1:20.3 | Fn3 3 ft (914 mm)[8] | Fn2 2 ft (610 mm) | ||||||||||||||||||||
| G scale | 1:22.5 | IIm G[ng 3] 1,000 mm (3 ft 3+3⁄8 in) | Gn15[ng 4] 15 in (381 mm) | Gnine 8 in (203 mm)[10][11] | Miniature ride-on | ||||||||||||||||||
| H scale | 1/2" | 1:24 | H 3 ft 6 in (1,067 mm) | ||||||||||||||||||||
| 3/8" | 1:32 | 3/8n20 20 in (508 mm)[12] | |||||||||||||||||||||
| P34 | 9mm | 1:34 | P34[ng 5] 3 ft 6 in (1,067 mm) | ||||||||||||||||||||
| O scale [i] | 7mm | 1:43.5 | On42[ng 6] 3 ft 6 in (1,067 mm) | O21[ng 7] 3 ft (914 mm) | O16.5[ng 8] 2 ft 4 in (711 mm) | O14[ng 9] 2 ft (610 mm)[19] | O9 / On15[ng 10] 15 in (381 mm) | ||||||||||||||||
| 1:45 | 0e[ng 11] 750 mm (2 ft 5+1⁄2 in) | 0p[ng 10] 400 mm (15+3⁄4 in) | |||||||||||||||||||||
| 1⁄4" | 1:48 | On42[ng 6] 3 ft 6 in (1,067 mm) | On3[ng 12] 3 ft (914 mm) | On30 / On21⁄2[ng 13] 2 ft 6 in (762 mm) | On2[ng 14] 2 ft (610 mm) | On20[ng 15] 20 in (508 mm)[21] | On18 18 in (457 mm) Of 450 mm (17+23⁄32 in) | ||||||||||||||||
| 1:50 | Pempoul [ng 16] 1,000 mm | ||||||||||||||||||||||
| 6mm | Towy Valley Tramway [ng 17] 2 ft (610 mm) | ||||||||||||||||||||||
| 5.5 mm | 5.5mm | 1:55 | 5.5 mm[ng 18] 3 ft (914 mm)[26] | 5.5 mm[ng 18] 2 ft (610 mm)[25] | |||||||||||||||||||
| S scale | 3/16" | 1:64 | Sm[ng 19] European metre gauge | Sn3[ng 21] 3 ft (914 mm) | Sn2 2 ft (610 mm)[30] | Sn2[ng 22] 2 ft (610 mm)[27] | |||||||||||||||||
| 00 scale | 4mm | 1:76.2 | Irish broad gauge[31] | 00n3[ng 23] 3 ft (914 mm) | 00-9[ng 24] 2 ft 3 in (686 mm) | 500 mm (19+3⁄4 in) 495 mm (19+1⁄2 in) | |||||||||||||||||
| H0 scale | Japanese HO aka #16 aka J | 1:80 | JM 3 ft 6 in (1,067 mm)[32] | H0e[ng 25] | |||||||||||||||||||
| 3.5mm | 1:87 | H0m[ng 27] 1,000 mm HOn31⁄2[ng 28] 3 ft 6 in (1,067 mm) | HOn3[ng 29] 3 ft (914 mm) | H0f/H0i[ng 30] 600 mm (1 ft 11+5⁄8 in) | H0p[2] | ||||||||||||||||||
| TT scale | 3 mm | 1:100 | TTn3[ng 32] 3 ft (914 mm) NZ120[28] | ||||||||||||||||||||
| 1:120 | TTf/TTi gauge[2] | ||||||||||||||||||||||
| N scale | UK N scale | 1:148 | |||||||||||||||||||||
| Japanese N scale | 1:150 | Nj gauge[citation needed] | |||||||||||||||||||||
| 2mm | 1:152 | ||||||||||||||||||||||
| 1:160 | Nm Nn3[ng 33] | Ne gauge[2] | |||||||||||||||||||||
| Z scale | 1:220 | Zm gauge[2] | |||||||||||||||||||||
| T scale | 1:450 [ii] | T gauge 3 ft 6 in (1,067 mm) | |||||||||||||||||||||
- Standard gauge is shaded
Gauges
See also
Notes
