The Definitive Guide to Model Railroad Scales-What you Need to Know

When beginning a model railroad, the first thing new modelers look at is the size of the trains that they want to model. This can be overwhelming as there are many scales to choose from.

When choosing a scale, you may come across the dilemma of figuring out the difference between scale and gauge, which are very different, but are incorrectly used interchangeably. First, scale and gauge are different. Scale is the size of the model compared to the full-size train. Gauge is the distance between the rails on the track.

Here we will talk about scales and their different sizes, and which scale may be right for your next model railroad.


Z Scale (1:220)

Z Scale is the smallest scale available for model railroaders. Developed by Marklin in Germany, this scale is 1:220, and has a track gauge of 6.5mm. It’s called Z scale because when it was developed, they assumed that there would not be the possibility of a smaller scale, so they picked the last letter of the alphabet. At first, this scale was mainly used in Europe, however, caught on in the rest of the world. Z scale railway clubs and manufacturers actively participate in model railway events throughout the world, demonstrating the effectiveness of the smooth driving mechanisms, detailed exteriors, and the ability to be equipped with digital decoders. Z scale has turned into a popular scale, as locomotives, rollingstock, track, etc. has been commercially produced by many fast-growing model railway companies.

Z Scale Manufacturers:

Micro Trains



American Z Line

N Scale (1:160)

N scale is a popular scale that is either 1:148 or 1:160. This scale is called N because the N means nine for the 9mm gauge, the distance between the rails. N scale is popular because it allows modelers to build layouts in a small space(or even in a coffee table). There are also more locomotives and rollingstock available for this scale than Z scale, which makes it more popular, in fact it is second in popularity behind HO. N scale became popular with modelers wanting to have scenic layouts and many trains, but with limited room.

N Scale Manufacturers:

Atlas Model Railroad Co.                               Bowser

Athearn                                                                 Kato

Bachmann                                                        Fox Valley Models

Broadway Limited                                         Intermountain

Exact Rail                                                            Walthers


HO Scale (1:87)

HO scale is the most popular scale on the market today, being the chosen scale for many model railroaders. HO is abbreviated for “Half O” meaning it is half the size of the larger O Scale. This scale became popular because they were smaller and less expensive than the trains on the O scale market.

HO Scale is very popular as there are endless amounts of locomotives and rolling stock available. It is the choice for many modelers because it is the perfect size, not as small as N or Z Scale, but not as large and space consuming as O scale. There are hundreds of manufacturers that produce HO scale trains worldwide. Most HO Scale trains run on either DC current or DCC Command Control, however, Marklin HO Scale trains run on AC current and pick up electricity from a string of studs in the rail gauge.

In HO scale, there is standard gauge and narrow gauge. Standard is the most common gauge and is the universally used gauge for HO scale trains. Narrow gauge in HO is called HOn30, and rides on N scale track, this makes it important to recognize the difference between scale and gauge. No matter what era, or railroad you choose, HO scale has a wide variety of accessories to choose from.

HO Scale Manufacturers:

Atlas Model Railroad Company                                 Broadway Limited Imports

Athearn                                                                       Marklin

Bachmann                                                                   Fox Valley Models

Bowser                                                                        Scaletrains

Kato                                                                            ExactRail



Photo: Tcost105

OO Scale (1:76.2)


OO scale is the most popular scale in the UK, and uses a 16.5mm wide track gauge. OO scale was started in the 1920s by German company Bing, and eventually caught on to the British market. It is popular in the UK because there are many different models and accessories that are widely available to purchase. The U.S. attempted to produce OO scale trains in the 1940’s, but was soon surpassed by HO scale.

OO Scale Manufacturers

Hornby                                                            Heljan

Bachmann Branchline                              ViTrains (formerly Lima)




S Scale (1:64)

This scale is one of the oldest scales in the world, originating in England in 1896, the first S scale model was made from pasteboard. S scale track gauge is measured at 22.43mm, and is operated using both DC and AC current.

This scale was popular with the American Flyer series of trains (manufactured by A.C. Gilbert Co.), which were S scale trains that ran on O gauge track. These trains were popular because they ran on realistic two rail track, in comparison with Lionel, who ran on 3 rail track.

While many S scalers collect American Flyer trains, there are also many new companies who manufacture modern S scale trains such as American Models and Pikesville Models. Accessories for this gauge are few and far between, however, S scalers embrace the challenge to construct their own scenery and custom painted trains.

S Scale Manufacturers:

American Flyer

American Models

Pikesville Models


O Scale (3 Rail) (1:48)

You may think of O scale when you hear the name “Lionel”, as they are a popular O scale manufacture that has been around since 1900 and is adored by many. O scale 3 rail is a popular scale that uses 3 rails to conduct electricity. O scale was introduced during a time when model trains were still considered toys and were made to be handled by children, thus, there weren’t many detail parts. However, as the scale matured, manufacturers began introducing fine scale details to this scale. O scale is popular, however, in order to build a full layout with scenery, you will need substantial room for the layout.

O scale modelers can model narrow gauge layouts with O-27 gauge, which was popular among the manufacturer American Flyer. The scale of locomotives for narrow gauge in O scale is 1:64 and is called O-27 because of the size of the track curves.

There is also O scale two rail, which is also 1:48 scale, and is made to look more realistic with the two-rail design.

O Scale Manufacturers

Atlas O



Williams by Bachmann

O Gauge Railroad Forum

G Scale (1:24)

G scale or “Garden Scale” is one of the largest scales and are known for their durability, some companies, such as LGB, even make their G gauge trains water resistant! G scale was introduced in the 1960’s and have given modelers the challenge of building layouts in their outdoor gardens. G scale trains have limited accessories and rolling stock to purchase, however, many modelers improvise and create their own.

G Scale Manufacturers




Aristo Craft


Lifelong Rail Enthusiast and Owner of Worldwide Rails

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