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S scale (or S gauge) is a model railroad scale modeled at 1:64 scale, S scale track gauge (space between the rails) is 0.883 in (22.43 mm).[1][2][3] S gauge trains are manufactured in both DC and AC powered varieties. S gauge is not to be confused with toy train standard gauge, a large-scale standard for toy trains in the early part of the 20th century.

S scale
Scale316 inch to 1 foot
Scale ratio1:64
Model gauge0.883 in (22.43 mm)
Prototype gauge1,435 mm (4 ft 8 12 in) standard gauge


S Scale is one of the oldest model railroading scales. The earliest known 1:64 scale train was constructed from card in 1896.[4] The first working models appeared in England in the early 20th century.[4] Modeling in S Scale increased in the 1930s-1940s when CD Models marketed 3/16" model trains.

American Flyer was a manufacturer of Standard Gauge and O gauge "tinplate" trains based in Chicago, Illinois. It never produced "S" Scale trains. Chicago Flyer was purchased by A.C. Gilbert Co. in the late 30s. Gilbert began manufacturing "S" scale trains in around 1939 that ran on three rail "O" gauge track. This was known as 3/16" O Gauge. Gilbert stopped producing trains during WWII. When the war ended, Gilbert began producing true "S" Scale "S" Gauge trains in 1946.

The term "S Scale" was adopted by the National Model Railroading Association (NMRA) in 1943 to represent that Scale that was half of 1 gauge which was built to 1:32 scale. A.C. Gilbert's improvements in 1:64 modeling and promotions of S gauge largely shaped the world of 1:64 modeling today.

S gauge entered what many consider its heyday in 1950s (although there is more available in S scale today than was available during this period) . However, during that period, Lionel outsold American Flyer nearly 2 to 1. American Flyer's parent company went out of business and the brand was sold to a holding company that also owned Lionel in 1967.

Lionel re-introduced S gauge trains and accessories under the American Flyer name in 1979. Another S manufacturer, American Models, entered the marketplace in 1981 and is now also one of the major S suppliers. S-Helper Service, another major S gauge manufacturer of locomotives, rolling stock, track and other products, began operations in 1989 and delivered their first S products in 1990. In 2013, S-Helper Service was sold to MTH Electric Trains. And while the S scale market has seen a number of brass model manufacturers, today the major brass model supplier in S scale/S gauge is River Raisin Models. Today's S gauge/S scale modelers have a greater selection and higher quality products, from a wide range of manufacturers, that at any time in the past. In addition to the basics of locomotives, rolling stock, and track, various manufacturers now offer S scale structures, detail parts, figures, other scenic items, bridges, and more.


The terms "Scale" and "Gauge" are often confused. Strictly speaking, scale is the ratio of the size of a model to that of its prototype and gauge is the distance between the track railheads. In the Case of "S" Scale, the proportion is 1:64 or 3/16" equals 1 foot. Standard "S" gauge is 7/8". Three foot gauge in "S" Scale (Sn3 gauge) is 14.28 mm (0.562 in).

In the 1920s and 30s toy trains were built of plated & lithographed tinplated steel. Since they were toys and not models per se, wheels and couplers were oversized. They were designed more for ease of use and robust service rather than pure fidelity of reproduction. Details were often represented as simple graphics on the models or even omitted altogether. Enthusiasts of toy trains are sometimes known as "tinplaters."

Very little "S" scale equipment was ever "tinplate." American Flyer does have oversized wheel flanges and couplers. A better term for American Flyer enthusiasts is "Highrailers." Highrailers, both collectors and operators, are a large and enthusiastic group with a brisk trade in both vintage and contemporary models. Many annual public events are held to promote and proudly display Highrail equipment.

Production methods have improved over the years making it possible for more accurately detailed models to be made available. These models have smaller flanges and couplers and in these respects are closer to actual proportions. They can also be finer detailed. In an effort to distinguish these efforts from the "highrail" products, the term "scale" has been adopted by the adherents of this "higher fidelity" approach. Examples of scale equipment are seen at many shows every year. Highrail and "Scale" can be compatible because they are both made to "3/16" Scale and 7/8" gauge. It is a matter of degree of fidelity to the real thing.

Narrow GaugeEdit

  • Sn3½ gauge - 3 ft 6 in (1,067 mm) gauge on 16.5 mm (0.65 in) gauge track (the same as HO gauge)
  • Sm – 1 m gauge on 16.5 mm; Continental European.[5]
  • Sn3 - 3 ft (914 mm) gauge on 14.3 mm (0.563 in) gauge track.
  • Sn2 gauge - 2 ft (610 mm) gauge on 10.5 mm (0.413 in) (the same as HOn3 gauge) or 9 mm (0.354 in) gauge track


The S Scale SIG is an NMRA-affiliated Special Interest Group dedicated to promoting and providing information on scale model railroading at 1:64. The National Association of S Gaugers serves as an organization to promote all forms of S gauge model railroading. The S Scale Model Railway Society also works to promote the scale in the UK.

Notable LayoutsEdit

The largest S Scale layout in the United States is the Cincinnati in Motion[6] exhibit at the Cincinnati Museum Center at Union Terminal


  1. ^ "What is S scale?". National Association of S Gaugers. 2017-09-23. Retrieved 2018-03-14.
  2. ^ "S-1.2 General Standard Scales" (PDF). NMRA. July 2009. Retrieved 2018-03-14.
  3. ^ "S-3.2 Trackwork Standard Scales" (PDF). NMRA. February 2010. Retrieved 2018-03-14.
  4. ^ a b S Scale MRS Standards: History
  5. ^ "Normen Europäischer Modellbahnen Maßstäbe, Nenngrößen, Spurweiten" (PDF) (in German). NEM. 2011. Retrieved 2014-05-15.
  6. ^ Cincinnati in Motion

See alsoEdit