Chapter 3 : Scale, Gauge & Standards

You'll hear model railroaders utter the terms "scale and gauge" in one breath. This may leave you breathless, totally confused. Now here's your chance to separate the scale from the gauge -- once and for all!

So now that you know why so many people have fallen in love with this hobby, you're interested in knowing a bit more. What? You said you're intimidated by it all, just because of two basic words: scale and gauge.

Ha! There's absolutely no reason for you not to understand these. These terms appear more intimidating than they really are. So, let's tackle them one at a time, so you can see exactly what they mean -- and how you they can become a part of your new language.

So you've already walked into your local hobby shop asking about model trains. And I can hear the conversation now. They asked you all sorts of questions about what types of model trains you wanted to start with, like HO or maybe N or perhaps O, or then you might find S better suited to your tastes.

And you walked out, empty handed, feeling not only disappointed, but like you just ate of bowl of alphabet soup? I only know this because it happened to me my first time in a hobby shop. And I left frustrated. But I also left determined to figure out what those clerks were talking about.

 So, before you make your next trip to the same shop, brush up with this chapter. I guarantee you, you'll not only know more about the questions they're asking, but you'll also be in the position to ask some questions of your own.

What is scale ?

Once you get into this hobby (and I assure you that you will!) you'll hear a lot of people bandy about the term scale. Scale is, in a nutshell, is the ratio of the model train to the life-size or "prototype" train.

Scale actually means exactly what the name implies. That the model you're running or building is a "scaled down" replica of the life-size version. The different letters assigned to the scales just reflect the natural differences in ratios.

Gauge, though sometimes spoken in the same breath as scale, is slightly different. It actually measures the width of the tracks on which your train runs.

Let's stop here for just a moment to consider the importance of gauge, especially. The success of the hobby lies in part because the manufacturers of these trains are precise enough with their processes to ensure that the trains the actually fit on the track. This wouldn't be so difficult if there were just a single maker of tracks and trains. Then you'd know for certain everything fit well together. But thankfully we have lots of choices. And it only benefits our hobby!

Imagine this scenario if the makers of different makers used all sorts of various sizes of gauges. You bring home a new locomotive to put on your track. And it doesn't fit.

When you talk track, it has to be absolutely accurate, even just a little off -- you may not be able to even see it at a glance -- for the train to be misaligned with the track.

The easiest way to explain them is to just tackle different train sizes and speak of both scale and gauge at the same time. But keep in mind that they really are two quite different aspects of the hobby.

Large-scale trains

This is the term the modelers used to describe, surprisingly enough, the larger selections. These models come not in just one scale but several. They all, however, operate on what's called Gauge 1 track. This track has 45 mm between either rail.

In fact, if you walk into a hobby store today, you'd probably discover at least five different scales all literally clumped together in this larger scale size.

Many of these trains are used by those aficionados who run their systems outdoors in their backyards. The locomotives chugged along carrying their cars through large flower and herb gardens.

So just how large are these trains? Well, imagine the size of a large 50-foot-long locomotive. The model of this, in a 1:29 scale (1 inch represents 29 feet) would be approximately 20 ¾ inches!

The most popular gauge is the "O" as it's called among hobbyists. The gauge for "O" is 1 ¼ inches; the scale is 1:48. That same 50-foot-locomotive in this model, is about 12 ½ inches long.

Just a bit smaller than "O" is the S-gauge train models. This category runs on tracks with a gauge of 7/8 inches and a scale of 1:64. Our prototype 50-foot locomotive is only 9 3/8 inches long in this scale.

Small but mighty . . . popular that is!

Yes, these are the largest of the trains. So, just how small are the small ones you may be wondering. I'm glad you asked. Let's find out just how small these trains can get!

There's the HO gauge. HO literally stands for "half of O". This class of trains is built to be exactly one half the size of "O" gauge models. When compared to the full-size trains, the HO has a scale of 1:87. Now, that makes our 50-foot life-size prototype 7 inches in this scale.

On first impression, you make think that this is extremely small. But, the HO train models are an ideal size to allow a satisfying layout in a smaller space. But, at the same time, these cars are large enough to display detail. And they really aren't too small to work with.

It's no wonder that HO is the most popular of all model railroad scales. More than two-thirds of modelers rank it as their favorite size!

But we go even smaller than that when we view the "N" scale. This model, with a ratio of 1:160, has a gauge of 9 mm between the rails. It's preferred by those who don't have the room they'd like for their layout. Those individuals who love expansive scenery also appreciate this gauge.

Now, we get to "Z" scale trains. Yes, they are even smaller than the others. Their scale to the prototype locomotive is 1:220. Yes. Imagine that. This size means that our 50-foot locomotive is only 2 ¾ inches long in the "Z" scale. The space between this model's scale is 6.5 mm.

Now for the lesser known scales . . .

When you're first starting out, it's doubtful that you're likely to choose the scale popularly known as "TT". Called the "scratch builders' scale," the ratio is 1:10, modelers must build  from "scratch" just about all of their pieces (as we go along, you'll see the term "scratch builders" frequently.)

While not extremely popular here, the TT scale gained a wide following in Europe and Australia where it's readily available. Today, some of these kits are being imported into the United States for the die-hard -- if small -- following.

Don't be surprised to see, as you spend more time in this hobby a revival of this scale. Cottage industries are cropping up specialized in manufacturing this size. New processing methods are available today that weren't available even a decade ago to make this possible.

Resin casting, for example, is now cheap enough that help to make this within the reach of many. If you have an extra $50 and just a little imagination you, too, can create your own line of TT scale model trains. Brass etching -- another needed process -- can be easily performed in the small, home workshop.

Standards for the Hobby

Yes! Yes! I see you're just shaking your head. And I can just about read your mind: How in the world can all the manufacturers keep all these scales and gauges straight. And who in the world actually keeps track of this -- if anyone?

Ahh! I'm so glad you're asking these questions, because that brings us nicely to our next topic: standards. Yes, this is one hobby in which standards are vitally important.

A standard, as defined by the railroaders, is a figure, relationship or a dimension that is absolutely mandatory. These relationships and dimensions must be adhered to if you're to call what you're producing a specific scale.

Standards may be changed, but only by the vote of the group in charge of the rules.

If some standards weren't put in place you can easily see how the entire avocation could fall apart -- quickly. That was exactly the problem in the early days of model railroading -- the 1930s.

No standards existed then. You could buy two different brands of models thinking they would work together because well . . .they were the same size. You'd bring them home only to find that one brand didn't fit on the other's tracks. Now that's a bummer.

In many cases, modelers would independently build to their own private standards or from their own ideas and their own designs. When this happened it became nearly impossible to go to any type of model railroad show. It was nearly impossible to interchange trains on tracks.

Order from railroad chaos

In 1935, model railroaders, manufacturers as well as publishers came together to discuss the (woeful) state of affairs in the hobby. Everyone in attendance agreed the hobby would fall apart if something weren't done to organize it in some way.

The creation of the National Model Railroaders Association and its standards came from this initial summit. These standards insured that equipment could be used from one model railroad brand to another. It also made the movement of cars and locomotives of varying brands interchangeable as well.

Surprisingly many of these ideas have held up quite well for more than 70 years. Today, many of the concepts are virtually unchanged from their original conception. Oh sure, the NMRA have elaborated on some of them, refined others and even added several more along the way. But the fundamentals are much the same when they were adopted in 1936 following that initial meeting.

And through the perspective of history, these standards are in large part the reason the hobby is as popular as it is today.

Then what is a recommended practice?

In addition to standards, you'll also run into a phrase call recommended practices -- normally abbreviated as RP. These are the figures, relationships and dimensions that the engineering committee of the NMRA has developed by way of testing.

Recommended practices are not mandatory as the standards are. They are not voted on by the membership either. But they are presented to the Board of Trustees of the NMRA for their study and approval.

As the name implies, it's recommended that all modelers follow these practices, but it certainly is not written in stone, as it were.

Now that we've cleared up some of the confusion about scale and gauge as well as shown you one of the reasons why the hobby has grown over the last 70 years -- and still flourishes today -- let's investigate what it's really all about -- the trains, the tracks, the layout and scenery.

"Next Stop, Benchwork!"

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