Large scale or G scale
(45 mm or 1 3⁄4 inches, G gauge) is a track gauge for model railways which, because of its size and durability, is often used outdoors. These garden railways use a fixed track gauge of 45 millimetres (1.75 in) to represent a range of rail transport modelling scales between narrow gauge (~1:13‒1:19‒1:20), metre gauge (1:22.5), Playmobil trains (~1:24), and standard gauge (~1:29–1:32). These scales all use the same track and wheel profiles, allowing different scales of models to be operated together2. O Scale
O scale (or O gauge)
is a scale commonly used for toy trains and rail transport modelling. Originally introduced by German toy manufacturer Märklin around 1900, by the 1930s three-rail alternating current O gauge was the most common model railroad scale in the United States and remained so until the early 1960s. In Europe, its popularity declined before World War II due to the introduction of smaller scales.
O gauge had its heyday when model railroads were considered toys, with more emphasis placed on cost, durability, and the ability to be easily handled and operated by pre-adult hands. Detail and realism were secondary concerns, at best. It still remains a popular choice for those hobbyists who enjoy running trains more than they enjoy other aspects of modeling, but developments in recent years have addressed the concerns of scale model railroaders making O scale popular among fine-scale modellers who value the detail that can be achieved.
HO or H0
is a rail transport modelling scale using a 1:87 scale (3.5 mm to 1 foot). It is the most popular scale of model railway in the world. The rails are spaced 16.5 mm (0.650 in) apart for modelling 1,435 mm (4 ft 8 1⁄2 in) standard gauge tracks and trains in HO.
The name HO comes from 1:87 scale being half that of O scale, which was previously the smallest of the series of older and larger 0, 1, 2 and 3 gauges introduced by Märklin around 1900. In most English-speaking markets it is pronounced “aitch-oh” and written with the letters HO today, but in other markets remains written with the letter H and number 0 (zero), so in German it is pronounced as “hah-null”.
is a popular model railway scale. Depending upon the manufacturer (or country), the scale ranges from 1∶148 to 1∶160. In all cases, the gauge (the distance between the rails) is 9 mm or 0.354 in. The term N gauge refers to the track dimensions, but in the United Kingdom in particular British N gauge refers to a 1∶148 scale with 1∶160 (9 mm or 0.354 in) track gauge modelling. The terms N scale and N gauge are often inaccurately used interchangeably, as scale is defined as ratio or proportion of the model, and gauge only as a distance between rails. The scale 1∶148 defines the rail-to-rail gauge equal to 9 mm exactly (at the cost of scale exactness), so when calculating the rail or track use 1∶160 and for engines and car wheel base use 1∶148.
is one of the smallest commercially available model railway scales (1:220), with a track gauge of 6.5 mm / 0.256 in. Introduced by Märklin in 1972, Z scale trains operate on 0–10 volts DC and offer the same operating characteristics as all other two-rail, direct-current, analog model railways. Locomotives can be fitted with digital decoders for independent control. Model trains, track, structures, and human/animal figures are readily available in European, North American, and Japanese styles from a variety of manufacturers.