H0 Scale

.tags History

H0 scale steam locomotives at the N&W RR museum in Crewe, Virginia.

The name H0 is derived from the fact that its 1:87 scale is approximately half that of 0 (zero) scale, hence H0. 0 scale in turn was named following the older and larger 1, 2, and 3 scales. The term H0 is pronounced (“aitch-oh” — that is, the letters “h” and “o”), not “ho” nor “aitch-zero”.

H0 scale trains first appeared in the United Kingdom in the 1930s, originally as an alternative to 00 gauge, but could not make commercial headway against the established 00 gauge. However, it became very popular in the United States, where it took off in the late 1950s after interest in model railroads as toys began to decline and more emphasis began to be placed on realism in response to hobbyist demand. While H0 scale is by nature more delicate than 0 scale, its smaller size allows modelers to fit more details and more scale miles into a comparable area.

In the 1960s, as H0 scale began to overtake 0 scale in popularity, even the stalwarts of other sizes, including Gilbert (makers of American Flyer) and Lionel Corporation began manufacturing H0 trains.

Currently, H0 is the most popular model railroad scale in both continental Europe and North America, whereas 00 gauge is still dominant in Britain.

There are some modelers in Great Britain who use H0 gauge. For them, the British 1:87 Scale Society was formed in 1994; it publishes a quarterly journal with news, views, and practical advice for modelers and collectors.

Today, H0 locomotives, rolling stock (cars or carriages), buildings, and scenery are available from a large number of manufacturers in a variety of price brackets.


Modern H0 trains run on two-rail track, which is powered by direct current (varying the voltage applied to the rails to change the speed, and polarity to change direction), or by Digital Command Control (sending digital commands to a decoder in each locomotive). Some trains, most notably by Mrklin of Germany, run on alternating current, supplied by a “third rail” consisting of small bumps on each tie down the center of the track.

On simple, usually temporary layouts, power is supplied by a power pack consisting of a transformer and rectifier, a rheostat or potentiometer for regulating voltage supplied to the track (and thus train speed), and a switch to control train direction double pole, double throw slide or toggle switch wired to reverse the polarity on the rails. On permanent layouts, multiple power supplies are traditionally used, with the trackage divided into electrically isolated sections called blocks; toggle or rotary switches (sometimes relays) are used to select which power supply controlled the train in a particular block. With the advent of digital command control, block divisions are largely eliminated, as the computerized controllers can control any train anywhere on the track at any time, with minor limitations.


H0 scale has several gauges representing both standard and narrow gauges in roughly 1:87 scale. Standards are defined by the NMRA (in North America) and the NEM (in Continental Europe). While the standards are in practice interchangeable, they are not strictly identical.

Track gauge





HO (NMRA) and H0 (NEM)

Standard gauge

16.5mm track is also used for British OO Gauge


HOn3-1/2 (NMRA) and H0m (NEM)

Metre gauge and 3’6″ gauge

3′ 6″ is the “standard” gauge in much of Africa, Queensland (Aus), New Zealand and also non-Shinkansen JR lines in Japan. HOm and HOn3-1/2 use commercially available TT scale track.



36″ gauge

36″ gauge once common to American mining railroads and shortlines, particularly in the Western States


HOn30 (NMRA) and H0e (NEM)

30″ gauge

Typically used for lines in 24-30″ gauge. Uses commercially-available N scale track.


HOz (NMRA) and H0i (NEM)

15″ gauge

Uses commercially available Z scale track.


The earliest track available was “sectional track,” available in a variety of standardized lengths, such as the ubiquitous 9″ straight and curved tracks of 15″, 18″, and 22″ radii. These are representative of curves as tight as 108feet (33m), which in the real world would only be found on some industrial spurs and light rail systems. With the introduction of “flex track,” which can be bent to any desired shape (within reason), it became possible to create railroads with broader curves, and with them more accurate models. Today it is common to purchase six-axle diesels and full-length passenger cars which will not run properly on curves less than 24″ in radius.

H0 scale track was originally manufactured with brass rail on plastic tie. Over time, track made of nickel-silver alloy became more common due to its superior resistance to corrosion. Today, almost all H0 scale track is of nickel silver, although Bachmann was up until quite recently manufacturing steel track.

In America, Atlas gained an early lead in track manufacturing, and their sectional, flex, and turnout track dominates the US market. In the UK, Peco’s line of flex track and “Electrofrog” (powered frog) and “Insulfrog” (insulated frog) turnouts are more common. Both Atlas, Bachmann, and Life-Like all manufacture inexpensive, snap-together track with integral roadbed. Kato also manufactures a full line of “HO Unitrack,” however it has not yet caught on as their N scale Unitrack has.

Rail height is measured in thousandths of an inch; “Code 83″ track has a rail which is .083” high. As H0’s commonly-available rail sizes, especially the popular “Code 100”, are somewhat large (representative of extremely heavily-trafficked lines), many modelers opt for hand-laid finescale track with individually-laid wooden sleepers/crossties and rails secured by very small railroad spikes.

In Australia, many club-owned layouts employ Code 100 track so that club members can also run OO-scale models and older rolling stock with coarse (deep) wheel flanges


Because of the scale’s popularity, a huge array of models, kits and supplies are manufactured. The annual H0 scale catalog by Wm. K. Walthers, North America’s largest model railroad supplier, lists more than 1,000 pages of products in that scale alone. Models are generally available in three varieties:

Ready-to-Run models are fully ready for use right out of the box. Generally this means couplers, trucks, 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 counterweight, while a structure kit might include walls, windows, doors, and glazing.

Craftsman Kits require a much higher level of skill to assemble and can include several hundreds of 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; on the other side 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.

Advantages compared to other scales

H0 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, 0 and G scales because of the smaller amount of material; the larger audience and the resultant economy of scale also drives H0 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, H0 scale provides the balance between the detail of larger scales and the lower space requirements of smaller scales.

H0 in other hobbies and in marketing usage

In other hobbies, the term H0 is often used more loosely than in railroad modeling. In slot car racing, H0 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 H0 size if they are close to an inch in height, though the actual scale is usually 1:76 or 1:72.

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 00, sometimes it split the difference (about 1:82). These items may be marketed as H0, especially in the US. In addition, some manufacturers or importers tend to label any small-scale model, regardless of exact scale, as H0 scale in order to increase sales to railroad modelers. The sizes of “H0” automobiles, for example, from different manufacturers, can vary surprisingly.


This transport-related list is incomplete; you can help by expanding it.

Currently-active significant manufacturers and marketers of HO railroad equipment as of 2008, include:

Arlo-Micromodel resin cast models and kits

Athabasca Scale Models


Atlas Model Railroad



Bachmann Industries

BGR Group


Blackstone Models (H0n3)

Bowser Manufacturing


Broadway Limited Imports

Busch[disambiguation needed]

Campbell Scale Model

Century Foundry



Fast Tracks





Hamo – Two-rail DC version of Mrklin




Hodgdon Scale Models in Connecticut

Hornby Railways

Hunterline Craftsman Kits


InterMountain Railway

International Hobby Corp


Kanamodel Products

Kato Precision Railroad Models

Katsumi Trains



Life Like





Micro Metakit

Model Power

MTH Electric Trains


NMJ (norsk modell jernbane) Norwegian model railway



Pola[disambiguation needed]

Precision Craft Models, Inc.


Rapido Trains Inc(Canada).



Sachsenmodelle (part of the Tillig group)

Showcase Miniatures


Stewart[disambiguation needed]

Summit USA

Trix (part of the Mrklin group)

TMI Digital



Weinert[disambiguation needed]

Wm. K. Walthers

Woodland Scenics

Significant historical manufacturers and marketers of H0 equipment which are no longer active in H0, include



Associated Hobby Manufacturers (AHM)

Aurora Plastics Corporation

L.M. Cox

Ken Kidder

Lima – bankruptcy in 2004, later acquired by Hornby

Lindberg Models



Pacific Fast Mail (PFM)

Penn Line Manufacturing






Varney Scale Models

See also



Rail transport modelling scales

Rail transport modelling scale standards

External links

Wikimedia Commons has media related to: H0 scale

Layout Tours A-L and Layout Tours M-Z

Tony Cook’s H0-Scale Trains Resource Includes separate websites for many classic H0-scale model train product lines of the past; online catalog resources; links to current manufacturers; new release resource section for current and coming product releases.

Model Train Scales H0 Scale, N Scale, O Scale, and all the Rest Gives an overview of all model train scales, especially H0 scale.

Categories: Model railroad scales | Scale model scalesHidden categories: Articles lacking sources from September 2008 | All articles lacking sources | Incomplete transport lists | Articles with links needing disambiguation