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
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
1.1 Controls 1.2 Scale 1.3 Track
2 Comparison to other scales 3 Manufacturers 4 See also 5 References 6 External links
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.
At the 1935 Leipzig Spring Fair, an electric tabletop railway, Trix
Express, was displayed to a gauge described as "half nought gauge",
which was then abbreviated as gauge 00 ("nought-nought"). Märklin,
another German firm, followed suit with its 00 gauge railway for the
1935 Leipzig Autumn Fair. The
For Europe it is defined in the Normen Europäischer Modellbahnen
standard NEM 010 published by
MOROP as exactly 1:87. For North
National Model Railroad Association
Advertising gift of a Mercedes bus in HO
In other hobbies, the term HO is often used more loosely than in
railroad modeling. In slot car racing, HO does not denote a precise
scale of car, but a general size of track on which the cars can range
from 1:87 to approximately 1:64 scale. Small plastic model soldiers
are often popularly referred to as HO size if they are close to one
inch (25 mm) high, though the actual scale is usually 1:76 or
Even in model railroading, the term HO can be stretched. Some British
producers have marketed railway accessories such as detail items and
figures, as "HO/OO" in an attempt to make them attractive to modelers
in either scale. Sometimes the actual scale was OO, sometimes it split
the difference (about 1:82). These items may be marketed as HO,
especially in the US. In addition, some manufacturers or importers
tend to label any small-scale model, regardless of exact scale, as HO
scale in order to increase sales to railroad modelers. The sizes of
"HO" automobiles, for example, from different manufacturers, can vary
The "gauge" of a rail system is the distance between the inside edges
of the railheads. It is distinct from the concept of "scale", though
the terms are often used interchangeably in rail modelling. "Scale"
describes the size of a modeled object relative to its prototype.
Prototype rail systems use a variety of track gauges, so several
different gauges can be modeled at the same scale.
The gauges used in H
Track gauges used in HO/
Track gauge NEM NMRA Prototype gauge Notes
16.5 mm (0.65 in) H0 HO Standard gauge The most common gauge. The 16.5 mm (0.65 in) gauge is additionally used for standard gauge trains in British 1:76 OO gauge, and for narrow gauges by 1:64 Sn3½, 1:48 On30, On2½ and 1:22.5 Gn15.
12 mm (0.472 in)
10.5 mm (0.413 in)
HOn3 3 ft (914 mm) gauge 3 ft (914 mm) gauge once common to American mining railroads and shortlines, particularly in the Western States
9 mm (0.354 in)
2 ft 6 in (762 mm) gauge
Typically used for lines in 2 ft
(610 mm)-2 ft 6 in (762 mm) gauge. Uses
6.5 or 7 mm (0.26 or 0.28 in)
15 in (381 mm)–2 ft (610 mm) gauge
H0f uses commercially available
4.5 mm (0.177 in) H0p
12 in (305 mm)‒15 in (381 mm) "Park". Defined in NEM 010 for modelling 300–400-millimetre (10–15 in) gauge ridable miniature railways.
The earliest "pre-gauged" track available in the 1940s had steel rails
clipped to a fiber tie base. This was called flexible track as it
could be "flexed" around any curve in a continuous fashion. The
sections were sold as three-foot lengths, and the rail ends were
connected with a sheet metal track connector that was soldered to the
base of the rail.
As brass became more readily available, the steel rail was phased out,
along with its corrosion problems.
Ready-to-run models are fully ready for use right out of the box. Generally this means couplers, trucks (bogies), and other integral parts are installed at the factory, although some super detailing parts may still need to be attached. Shake-the-box kits are simple, easy-to-assemble kits; a freight car might include a one-piece body, a chassis, trucks, couplers, and a weight, while a structure kit might include walls, windows, doors, and glazing. The name derives from the joke that no skill was required – shake the box, and the kit falls together. A common synonym is screwdriver kit as many can be assembled with a screwdriver and tweezers. Craftsman kits require a much higher level of skill to assemble and can include several hundred parts.
In addition to these kits, numerous manufacturers sell individual
supplies for super detailing, scratch building, and kitbashing.
Quality varies extremely. Toylike, ready-to-run trains using plastic
molds which are well over 50 years old are still sold; at the other
are highly detailed limited-edition locomotive models made of brass by
companies based in Japan and South Korea. A popular locomotive such as
the F7/F9 may be available in thirty different versions with prices
ranging from twenty to several thousand dollars or euros.
Comparison to other scales
HO scale's popularity lies somewhat in its middle-of-the-road status.
It is large enough to accommodate a great deal of detail in finer
models, more so than the smaller N and Z scales, and can also be
easily handled by children without as much fear of swallowing small
parts. Models are usually less expensive than the smaller scales
because of more exacting manufacturing process in N and Z, and also
less expensive than S, O and G scales because of the smaller amount of
material; the larger audience and the resultant economy of scale also
drives HO prices down. The size lends itself to elaborate track plans
in a reasonable amount of room space, not as much as N but
considerably more than S or 0. In short, H
This transport-related list is incomplete; you can help by expanding it.
Currently active significant manufacturers and marketers of HO railroad equipment as of 2009, include, but are not limited to:
Accurail accurate lighting Acme Model Engineering Co. Albrae Models Arlo-Micromodel resin cast models and kits Athabasca Scale Models Athearn Atlas Model Railroad Auhagen Auscision Austrains AWM Bachmann Industries BGR Group BEMO (de) Blackstone Models (HOn3) Blair Line BLMA Models Bowser Manufacturing Brawa Brekina Broadway Limited Imports Busch Campbell Scale Models Century Foundry Electrotren (part of Hornby) Eureka Exactrail Faller Fleischmann (part of Modelleisenbahn GmbH) Frateschi Fulgurex Guetzold HAG
Hobbytown of Boston
Hodgdon Scale Models in Connecticut
Hunterline Craftsman Kits
International Hobby Corp
Lemaco Life-Like Liliput (part of Bachmann) Mantua Märklin Mehano Micro Metakit Model Power MTH Electric Trains MRmatiX Noch Norsk Modelljernbane (NMJ) Norev Northwest Short Line (NWSL)
Precision Craft Models, Inc.
Rapido Trains Inc (Canada).
Significant historical manufacturers and marketers of HO equipment which are no longer active in HO, include
Airfix American Railroad Models (American Beauty) Aristo-Craft Associated Hobby Manufacturers (AHM) Aurora Plastics Corporation Balboa L.M. Cox Globe Herkimer Kembel Ken Kidder Lima — bankrupt in 2004, later acquired by Hornby Lindberg Models Lindsay Products
Lionel Marx Olympic Express Pacific Fast Mail (PFM) Penn Line Manufacturing Powerline Models Revell Selley Train Miniature Trainorama Tru-Scale True Line Trains Trumpeter Tyco Toys Ulrich Varney Scale Models
^ "Guide to model railroading scales and gauges". Model Railroader. 2
November 2011. Retrieved 2 October 2016.
^ Johnson, Kent J., ed. (1998). Basic Model Railroading: Getting
Started in the Hobby. Kalmbach Publishing, Co. p. 6.
ISBN 978-0-89024-334-3. Retrieved 2017-10-24.
^ NMRA. "Modeling Scales: Scale and Gauge". NMRA.org. December 2000.
Retrieved 4 March 2010.
^ a b Johnson, Kent J. (Editor). Basic Model Railroading: Getting
Started in the Hobby, p 6. Kalmbach Publishing, Co., 1998. at Google
Books. Retrieved 12 March 2010.
^ Johnson, Kent J. (Editor). Basic Model Railroading: Getting Started
in the Hobby, p 7. Kalmbach Publishing, Co., 1998. at Google Books.
Retrieved 12 March 2010.
^ a b c d Maßstäbe, Nenngrößen, Spurweiten [Scales, nominal sizes,
gauges] (Specification) (Report). Normen Europäischer Modellbahnen
NEM (in German). 2011. p. 1. 1:87 … von 400 [mm] bis <650
[mm] … H0i … Im deutschen Sprachraum kann anstelle des
Zusatzbuchstabens i (Industriebahn) auch der Buchstabe f (Feldbahn)
^ "S-1.2 Standards for Scale Models" (PDF).
Wikimedia Commons has media related to H0 scale.
Layout Tours A-L and Layout Tours M-Z Tony Cook's HO-Scale Trains Resource Includes separate websites for many classic and contemporary HO-scale model train product lines of the past; online catalog resources; plus links to current manufacturers.
v t e
H0/HO modelling scale (1:87)
Rail track gauges
16.5 mm-H0 (standard) 12 mm-H0m (metre) 9 mm-H0e 6.5 mm-H0f
16.5 mm-HO/Proto:87 (standard) 12 mm-HOn3½ 10.5 mm-HOn3 9 mm-HOn