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

Scale 1:87
Original Gauge 1435 mm
Area of application Continental Europe
Scale 1:80
Original Gauge 1320 mm
Area of application Japan
Scale 1:76
Original Gauge 1254 mm
Area of application Great 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 Gauge H0
Original Gauge Normal gauge
Model Width 16,5 mm
Original Width 1435 mm
Possible use with 1250 - 1700 mm
Model Gauge H0m
Original Gauge Meter gauge
Model Width 12 mm
Original Width 1044 mm
Possible use with 900 - 1250 mm
Model Gauge H0e
Original Gauge Narrow gauge
Model Width 9 mm
Original Width 783 mm
Possible use with 675 - 900 mm
Model Gauge H0f (H0i)
Original Gauge Field- or industrial railway
Model Width 6,5 mm
Original Width 565 mm
Possible use with up 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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