HO scale model trains are 1/87 the size of real trains and 1/2 the size of O scale model trains (HO stands for "half O"). As with O scale trains, the letter "O" in HO is a misnomer since the designation was initially conceived as a zero to identify trains that were smaller in scale than 1. But the use of the letter O rather than the numeral 0 crept into everyday speech among model-train buffs and remains the standard way to refer to HO scale today.

Though first invented in the 1930s, HO scale model trains didn’t become popular in the U.S. and Europe until the 1950s when the scale was heavily promoted by Märklin, Lionel, Athearn, and others. HO never quite gained acceptance in England, though, where larger 00 scale trains still predominate.

HO has two important benefits over trains of larger sizes. First, an HO scale layout of reasonably ambitious detail and complexity can fit on a table rather than requiring an entire room, as is the case with larger scales. Second, HO trains are less expensive to manufacture than OO, O, and other large-scale trains, which makes them more affordable to collectors and enthusiasts alike.

Most HO scale trains run on two-rail tracks using direct current (DC). Adjusting the voltage delivered to the tracks can increase or decrease the speed of the trains; reversing the polarity causes the trains to roll in reverse. Some manufacturers, notably Märklin, produce HO scale trains that operate on alternating current (AC), which is delivered to the train via a conductive third rail.

The gauge used by the majority of HO scale model trains is a standard HO gauge track that’s roughly proportional to the size of the trains running on top of it. But as with the OO scale trains in England that run on HO gauge tracks, HO scale trains are also made to run on a variety of different gauge tracks, which themselves are scaled-down versions of historical railroad track sizes.

Of these variants, the most common is called HOn3. This code denotes an HO scale train running on a track similar to the 3-foot, narrow gauge tracks used by Rocky Mountain railroad operators in the late 19th century.

One of the most enjoyable aspects of HO for collectors is the opportunity to join a local module club. Members of such clubs build modules of predetermined size; each module has a finite length of track. When members get together at model train exhibitions or in private homes, the modules are linked up and trains are run on the resulting massive layout, which often feels like more than just the sum of its parts.

Best of the Web (“Hall of Fame”)



This site is a treasure trove of HO scale model railroad manufacturer catalogs and other reference information, inv… [read review or visit site]

Airfix Model Railways

Airfix Model Railways

Dave McCarthy's Airfix Model Railway treasure trove is an in-depth archive of the company's plastic railway kits fr… [read review or visit site]

Gateway NMRA

Gateway NMRA

This great reference site for model railroaders, from the Gateway (St. Louis) division of the NMRA (National Model … [read review or visit site]

Postwar Lionel Trains Library

Postwar Lionel Trains Library

Bernie Schulz’s Lionel Trains Library focuses exclusively on postwar Lionel trains and accessories. The site cont… [read review or visit site]

Eric's Trains

Eric's Trains

Eric Siegel's site displays his collection of O-gauge/O-scale trains, tracks, turntables, and other accessories. A … [read review or visit site]

Tech Model Railroad Club of MIT

Tech Model Railroad Club of MIT

MIT's model railroad club, as one might expect, has one of the best websites for learning about how people play wit… [read review or visit site]

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Recent News: HO Scale Model Trains

Source: Google News

Senior News: July 28 — Aug. 3
Milford Mirror, July 27th

Call for information on other tours including Colorado Rockies and Train Tour Sept. 5-13; Spain and Portugal River Cruise Oct. 3; Reflections of Italy ... The HO scale of model railroading will be used. Donations of any model railroading equipment or...Read more

Railroad Museum breaks ground for garden railroad city
Fort Bend Herald, July 25th

Its collection includes a fully refurbished private rail car, a red caboose, a replica of the Rosenberg Train Depot that houses train artifacts and the original Rosenberg switch tower. In addition an education station features a model train layout in...Read more

Make tracks to Historic Cold Spring Village for Railroad Days
Shore News Today, July 24th

On display in the Welcome Center will be the Strasburg Model Railroad Club's display of the Pennsylvania-Reading Seashore Lines HO scale layout. ... Free rides aboard the toy train will be available 11 a.m.-3 p.m. Saturday and noon-4 p.m. Sunday...Read more

Model train exhibit displayed at Plantation museum
Sun-Sentinel, July 24th

Its latest exhibit featuring operating model train displays and layouts is at the Plantation Historical Museum through Oct. 25. The society laid the groundwork for HO, O, G and N scales for visitors to enjoy. The gauges allow train enthusiasts to bring...Read more

Backyard transformed into railroad village
Spencer Daily Reporter, July 21st

"Shortly after that I got my first rail road train set, a HO scale train." At the time, Peterson was living in Alta. Although he has since moved his permanent location, the original train model that he had when he lived in Alta has stayed there. "I...Read more

Kalamazoo Model Railroad Historical Society expanding headquarters, train ...
Mlive Kalamazoo, July 11th

The refurbished caboose sits on a short line of track, surrounded by fully-functional crossing lights and alarms – a real-life example of the massive 20 foot by 40 foot HO-scale model railroad that takes up much of the space within the building. "We...Read more

Model Train Exhibit at Tellus Science Museum
Stephen Burge, July 10th

Members of the Central Georgia Model Railroad Club in Macon built these sets from scratch for an exhibition at Hartsfield-Jackson International Airport. It became so popular that this HO scale model train exhibit has toured several of Georgia's museums...Read more

New train exhibit at Oil Museum
Petrolia Topic, July 8th

“A train of oil hauling vehicles which represents the historical progression in the development of such cars is being built up one car at a time.” The display models are HO scale (HO scale model trains are 1/87th the size of a real train) and the...Read more