What is scale?<<BR>
Scale is the ratio between the model and the prototype; for example, N scale is 1/160th of the size of the real world.
The standard scales, listed in approximate order of popularity, are:
| G | 1/22.5 | Or 1/24, or whatever the manufacturer decides |
| No. 1 | 1/32 | |
| O | 1/48 | In O scale, track has been traditionally laid to scale 5'0" gauge instead of standard. O scale modelers divide into four groups according to how they handle the
discrepancy between gauge and scale: a. most O scalers live with the discrepancy. b. some model at 1/45 scale, keeping the traditional O gauge. c. some model at 1/48 (known as Proto:48) and narrow the traditional guage to standard, but these models will not interoperate with the first two groups. d. European modellers use 7mm/ft, with 32mm track gauge (the fine scale folks use 33mm). 32mm gives a scale gauge just less than 4ft 7in, and 33mm gives marginally over 4ft 8.5in. |
| S | 1/64 | |
| OO | 1/76.2 | 4 mm to the foot, mostly used in the UK |
| HO | 1/87 | actually 3.5mm to the foot, or 1/87.1 |
| N | 1/160 | 1/152, 2mm per foot in the UK |
| Z | 1/220 | |
| TT | 1/120 | common scale in the former GDR, only produced by Zeuke in Berlin |
By design, this list only includes the common scales which most beginning modelers are likely to run into. There are many other scales and variations in scales (for example, OO is slightly
different in the US but virtually nobody uses it here), but this is a list of _frequently_ asked questions, not an exhaustive (and thus difficult to read) compilation of every scale known to
exist.
People build models in other (typically larger) scales, but they tend to be mostly scratchbuilt. 1/8th scale (1.5" to the foot) is a common size for outdoor models large enough to carry people.
Also, there is a sharp distinction between 0-scale trains/layouts, and O-gauge tinplate trains. The trains made by Lionel and other toy manufacturers are called "tinplate" (for historical reasons)
and run on 3-rail track. The original track has a rounded head and very tall rails (hence the term "hi-rail" is also used), although much more prototypical track is now made for 3-rail locomotives.
They typically use AC propulsion power. Confusion arises because both use "0 gauge", 1 1/4" between the rails. 0-scale models are built to 1/4" scale and typically are models of particular
prototypes. Tinplate models are typically made to a somewhat smaller scale and are often 'generic', i.e., they generally represent no one prototype, but rather give the general impression of a number
of real trains. Some more expensive tinplate trains are prototypical, and this is a increasing trend.
What is HOn3 scale?
This is HO scale equipment (1/87th) running on narrow gauge rails spaced 3 feet apart. Narrow gauge in other scales is represented in a similar fashion. There are similar notations for models whose
gauge is based on non-English measurements, such as HOm (HO scale, one-meter gauge) and HOe (HO scale, 0.80 meter guage (*)), as well as HOn30, which indicates 30" (2.5') gauge (**).
(*) The 'e' indicates 'eighty cm' as used on prototypes such as the Salzgamergut Railway in Germany.
(**) My understanding is that this is a compromise which approximates 2' gauge (once used widely by logging roads in Maine, among other places) but that allows standard gauge N scale drive mechanisms
to be used after replacing the wheels. I believe that both the 1992 and 1993 "Great Model Railroads" from Kalmbach include pictures of David Frary's "Carrabassett and Dead River" layout which is
HOn30. Since so few people model 2' gauge there is no supply of ready-to-run drives available and the compromise allows somebody who isn't a machinist to build the models.