HO scale

HO or H0 is the most popular scale of model railway in the world.

According to the National Model Railroad Association (NMRA) standard S-1.2 predominantly used in North America, in HO scale, 3.5 mm (0.1378 in) represents 1 real foot (304.8 mm); this ratio works out to 1:87.0857142, usually rounded to 1:87.1. According to the MOROP standard NEM 010 predominantly used in Europe, the scale is exactly 1:87. In HO, rails are spaced 16.5 mm (0.64961 in) apart which models the standard railroad gauge of 1,435 mm (4 ft 8 ¹⁄₂ in).

Derivation

The name HO is derived from the fact that its 1:87 scale is approximately half that of 0 scale which was the smallest of the series of older and larger 0, 1, 2 and 3 scales introduced by Märklin around 1900. In most English-speaking markets it is pronounced "aitch-oh" and written with the letters HO today, but in German it is pronounced "hah-null", and still written with the letter H and number 0.

History

After the First World War there were several attempts to introduce a model railway about half the size of 0 scale that would be more suitable for smaller home layouts and cheaper to manufacture. H0 was created to meet these aims. For this new scale, a track width of 16.5 mm was designed to represent prototypical standard gauge track, and a model scale of 1:87 was chosen. By as early as 1922 the firm Bing in Nuremberg, Germany, had been marketing a "tabletop railway" for several years. This came on a raised, quasi-ballasted track with a gauge of 16.5 mm, which was described at that time either as 00 or H0. The trains initially had a clockwork drive, but from 1924 were driven electrically. Accessory manufacturers, such as Kibri, marketed buildings in the corresponding scale.

Scale

Scale or scales may refer to:

Common meanings

Places

Mathematics

Science

Scale length (string instruments)

When referring to stringed instruments, the scale length (often simply called the "scale") is considered to be the maximum vibrating length of the strings to produce sound, and determines the range of tones that string is capable of producing under a given tension. In the classical community, it may be called simply "string length." On instruments in which strings are not "stopped" or divided in length (typically by frets, the player's fingers, or other mechanism), such as the piano, it is the actual length of string between the nut and the bridge.

String instruments produce sound through the vibration of their strings. The range of tones these strings can produce is determined by three primary factors: the mass of the string (related to its thickness as well as other aspects of its construction: density of the metal/alloy etc.), the tension placed upon it, and the instrument's scale length.

On many, but not all, instruments, the strings are at least roughly the same length, so the instrument's scale can be expressed as a single length measurement, as for example in the case of the violin or guitar. On other instruments, the strings are of different lengths according to their pitch, as for example in the case of the harp or piano.

Scale (map)

The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. This simple concept is complicated by the curvature of the Earth's surface, which forces scale to vary across a map. Because of this variation, the concept of scale becomes meaningful in two distinct ways. The first way is the ratio of the size of the generating globe to the size of the Earth. The generating globe is a conceptual model to which the Earth is shrunk and from which the map is projected.

The ratio of the Earth's size to the generating globe's size is called the nominal scale (= principal scale = representative fraction). Many maps state the nominal scale and may even display a bar scale (sometimes merely called a 'scale') to represent it. The second distinct concept of scale applies to the variation in scale across a map. It is the ratio of the mapped point's scale to the nominal scale. In this case 'scale' means the scale factor (= point scale = particular scale).