Gauge H0

The nominal size H0 (in English also HO) is the most common building size in model railway. It has a scale of 1:87, so the normal gauge a role model of 1435 millimeters leads to a gauge of 16, 5 millimeters in H0.


In the beginning of the 20th century, a scale of 1:45 (respectively 1: 43.5 in France and 1:48 in the US) was introduced for model trains and called gauge 0, resulting in a gauge of 32 millimeters. In 1935 first Trix and later Märklin introduced an electrical model train for tables in “half size 0” (=half zero) which later became the more or less standard for Europe.

At the same time the nominal size 00 was developed in Great Britain, which had the same gauge but the slightly different scale of 1:76. In Japan the nominal size H0 is used in scale 1:80. In the US the size is called HO instead of H zero. The market today in Europe is dominated by the nominal size H0 with the gauge H0.

Scales in comparison

Original Gauge1435 mm
Area of applicationContinental Europe
Original Gauge1320 mm
Area of applicationJapan
Original Gauge1254 mm
Area of applicationGreat Britain

Gauge in H0

The following model gauges are specified for the scale 1:87 in the European Model Railways (NEM) standards for Continental Europe:

Model GaugeH0
Original GaugeNormal gauge
Model Width16,5 mm
Original Width1435 mm
Possible use with1250 - 1700 mm
Model GaugeH0m
Original GaugeMeter gauge
Model Width12 mm
Original Width1044 mm
Possible use with900 - 1250 mm
Model GaugeH0e
Original GaugeNarrow gauge
Model Width9 mm
Original Width783 mm
Possible use with675 - 900 mm
Model GaugeH0f (H0i)
Original GaugeField- or industrial railway
Model Width6,5 mm
Original Width565 mm
Possible use withup to 675 mm

For the representation of meter gauge, narrow gauge and field railways in the nomi-nal size H0, the standard normal gauge tracks of nominal sizes TT, N and Z are suit-able (in addition to the standard tracks of the track H0m, H0e and H0f). From a tech-nical point of view there are no restrictions, apart from the usually narrower radii.

From a visual point of view however, there are of course some optical setbacks in comparison to the role model with respect to the thresholds (the threshold band). However, these can be visually concealed well in the base grade, especially for streetcars and field railways.

Track systems

Within the gauge H0 there are competing propulsion systems:

  • Two-track two-conduct system: DC voltage, each rail a potential (for example Fleischmann, Roco, Trix and Kleinbahn)
  • Three-track two conduct system (center conductor system):  AC voltage, both rails ground, center contact phase (only Märklin)
  • Three-track three-conduct system: DC voltage, each rail potential 1, Center contact common potential 2 (Trix Express, production discontinued)

Please note

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