Model Train Track Codes

When you first buy a train set, more often than not, it’ll come with a simple loop of track. But next thing you know, the box is talking about model train track codes, gauges and scales, and it all gets a bit overwhelming!

So, let’s dig a little deeper into model train track codes, and just what that exactly means for you!


What are model train track codes?

The NMRA establishes what model railroad track codes are – A train track code number is really the rail height presented in thousandths of an inch, so a Code 55 track is 0.055 inches tall. That’s all there is to it!

Companies will sometimes provide many different code options in scales, so just make sure that you keep an eye on what the code is when making a purchase!

Here is a breakdown of scales and the model train track codes that correspond to them:

O scale track codes: 125, 100

HO scale track codes: 100, 83, 70, 55

N scale track codes: 80, 55, 40

Z scale track codes: 55, 40

On a similar layout, you can incorporate different track codes so long as they’re the same scale. On mainlines and some sections, railways in the real world will frequently use various rail diameters depending on the landscape it’s going over.

When joining rails of various codes, you’ll require a transition joint, which is usually a type of straight joint bar.

It’s a smart option to design your railroad before buying any of them since you would need a clear idea about where the transition joints will be placed. Alternatively, and if at all possible, just make sure that all your track is the same model train track code!


Ho Model track code 83 vs. 100

The very first thing you should know is what the codes mean – when you see code 83 rail, you’re staring at a track with a rail height of .083″, whereas code 100 rail is .1″ in height.

Both of these codes are really popular due to differing factors:

Code 83 is 0.83″ tall, and because HO is 1/87 scale, it means that in the real world, it would be 7.2″, which is within .2 of an inch of real track – most common US track is 7″ in height.

Code 100 on the other hand, is actually way taller, scaling up to nearly 9″ in the real world! This would be a big deal in the real world, and glaringly obvious.

So if you’re used to staring at the actual thing, Code 83 will appear more lifelike.

However, after installing and ballasting the rail track, some enthusiasts have difficulty distinguishing between the two, because when shrunk down, there really is less than .2 of an inch between them.

So can you use code 83 and code 100 at the same time?

Several layouts might make use of several rail codes. For instance, on your main lines, you might use code 83 rail and then code 70 rail for the sidings and spurs.

Furthermore, not all types of rail are appropriate for all types of rolling stock. Much older rolling stock has bigger wheel flanges that prevent the wheel from seating correctly on the rail.

The majority of the latest rolling stock performs well on code 83 track.

But what about code 100 model train track you ask? Well, the advantage of Code 100 is that it can be purchased almost everywhere that offers HO model trains.

Code 100 is widely available, less expensive, and chances are good you most likely have some on hand if you are a model train enthusiast. Unfortunately these days, code 83 just isn’t as commonplace, so your local model train store might not even sell it.

Because of the size of their wheel flanges, certain trains, especially older trains that are less expensive, may perform better on Code 100 track than on Code 83 track.

So what does that mean for your model train track codes?

Some enthusiasts will deploy Code 83 in prominent sections of the arrangement, right up front, to receive the advantage of Code 83 at a reduced expense, like looking slightly more accurate.

However, they will utilize Code 100 in tunnels, other locations that are obscured from sight, including on parts of the layout that are inaccessible. This provides the advantage of Code 83 when it is visible and the affordability of Code 100 where it is not.

Some model railroaders may purchase a higher-grade code 100 track, which will have a genuine rail profile as well as excellent ties and spikes, so its up to you which method you’d prefer to go with.


Code 55 track

Code 55 has a lower rail height depending on the scale you’re using, with the code representing the rail height in thousands of an inch. So if you’re using HO scale at .55″ tall, it might actually look too short, but if you’re shrunk all the way down to Z scale at 1:220, it might actually look too big.

Code 55 has a significant benefit over Code 80 in that it provides uniform point geometry, as well as single and double slips.

Overall, we think that code 55 is probably just easier to use and deal with


Brass, nickel or silver model train tracks

Model train tracks are made from a variety of metals. You would have to decide whether to go with brass, nickel-silver, or steel rail, especially if you’re starting fresh.

Almost all HO track used to be constructed using brass rail, although they aren’t used nearly as often these days.

The golden hue, on the other hand, isn’t a natural colour, and brass must be maintained very polished for optimal electrical contact, so there is a lot more upkeep involved. The colour of the steel rail is great; however, the rails are tough to cut and file.

As it is an alloy of those two metals, the most common track nowadays is known as “nickel silver.” Nickel silver is preferred since it does not rust as quickly as other metals being used in model rails, which means it does not need to be cleaned as frequently, but still conducts an electrical current better or as good as both of the above.


If you’re going to be purchasing new rail, we’d suggest making sure that it’s Nickel Silver track, and then choosing a convenient model train track code for your layout.

The major difference is between expense and realism. Code 100 is more commonly accessible and less expensive, so you pay a premium for Code 83’s greater realism, or you may conclude the distinction isn’t significant enough.