Choosing a scale

[Revised on April 24]

I previously talked about the difference between Gauge and Scale, and in that post linked to a long but incomplete list of known scales. In this post I'll talk about choosing a scale. Some of the points in this post will be referenced in later posts on the design of the current layouts.

Let's suppose you wanted to build a layout with an American standard-gauge prototype. If you walked into a large multi-scale hobby shop like Caboose Hobbies these are the scales you'd find that have that kind of off-the-shelf equipment available:

• Z scale (1:220)
• N scale (1:160)
• HO scale (1:87)
• O scale (1:48)
• H scale (1:32)
• 1:29 scale (using H scale track)

Now, this is not a list of every known scale. But it is a list of scales that are popular enough to have several manufacturers that produce off-the-shelf American standard gauge prototype products for them.

If you were choosing from this list of scales you'd probably be able to eliminate 3 or 4 possibilities right away, depending upon your preferences. The factors that influence most people's choice of scale are these:

1. Availability. The most popular scale, HO, has a huge variety of items available. Less popular scales like O and Z have a very restrictive selection. If you want to model a particular road name, or era, or just have a hankering for certain types of locomotives, you may find that not every scale has the off-the-shelf equipment that you like.


2. Price. HO and N are the lowest cost on a price-per-item basis. This is partly due to popularity (economies of scale, plus competition), and partly due to the fact that it's more expensive to build models that are very large or very small.


3. Experience and/or existing equipment. For example, if you had an O scale layout as a kid you may lean towards using O scale again as an adult, especially if you have some old O scale equipment that can be reused. Similarly, if you have friends running N trak modules you are more likely to choose N so that you can interoperate with them.


4. Space. One of the frustrating things about model railroading is that unless you are very lucky you never have as much space as you want. This makes sense when you realize how huge the thing is that we are trying to model. A typical modern freight train is at least a mile long -- and a mile is over 60 feet in HO scale! Or suppose you just want to run an 8 car commuter train, but that is almost 9 feet long in HO -- not easy to fit on a 4x8 table! Then there are the curves -- the famous horseshoe curve on the old Pennsylvania Railroad is one of the tightest curves on a class 1 mainline in the U.S., but if you were to model it accurately in HO scale you'd need a half-circle with a diameter of over 14 feet! For these reasons it is not surprising that modelers looking for more realism have flocked to N and even Z scale. Not only can you squeeze a layout into a much smaller space, you can also use a larger space to create a more realistic setting.


5. Size. The counterpart to "space" is the size of the equipment you use. For some modelers, weakening eyesight or dexterity motivates them to take up a scale such as O or even to model a large scale indoors. For others the frustration of trying to do electrical or detailed modeling work on N or Z scale has pushed them to HO. Size vs. Space is always a major trade-off in choosing a scale.


6. Aesthetics. What do you think looks better? Some modelers love the appeal of large, chunky O scale stock rolling across the layout. Others like the great detail they can put into large scale models. Some love to create panoramic views of mountains, canyons, or just large freight yards in a way that's only possible in the smaller scales. But as most modelers choose HO, perhaps most modelers like a compromise of all of the above.

With those scale choosing criteria in mind, here's a quick review of the scales.

Large (H and 1:29) I explained how all large scales use the same gauge of track in a previous post. H and 1:29 are the scales you would use if you wanted to model standard gauge.

The main advantage of large scale is that it is intended primarily for running outdoors. Most large scale modelers do so outdoors, in a specialty of the hobby called "garden railroading". For many of us (and I am one) there is a special appeal of railroading outdoors. First, there are all the tactile sensations of just working outdoors. Second, while indoor railroading tends to be less social -- usually only other modelers want to hang around your layout -- outdoor railroading invites the world to join. Even if you don't like railroads you may still love the garden aspect, or working with ponds and streams, or just being outdoors.

Of course, there are disadvantages to outdoors. The environment is always changing, the weather may not cooperate, and you may not have a suitable yard to build in. It's not for everyone.

One more advantage of large scale is that the very large equipment just has a certain appeal. I mean, it's HUGE compared to the other scales. This is why a few people who don't like outdoor modeling still use large scale indoors.

The disadvantages of large scale are simple: price, the space required, and the time required. Engines commonly run in the thousands. Although entry level diesels can be had for under $200 the lack of detail relative to a $75 HO diesel is noticable. Track has become exhorbitant. And depending on how you construct your layout you may find yourself spending tens of thousands in landscaping. There are those who have successfully built very low cost garden railways, but they always make significant compromises and spend a very long time building a lot from scratch.

Meanwhile, big trains mean you need a lot of space to run them. And if you are building outdoors, the time required for construction is much more than if you build a comparable layout indoors.

Garden railroading, I'm told, is the fastest growing segment of the hobby. But it's not for everyone.

O scale (1:64) There are really two types of O scale. One is the standard 2-rail model train. The other is Lionel. Lionel was the leading classic toy train for most of the 20th century. Lionel trains weren't that realistic -- they used a 3 rail electrical system, the rails didn't look anything like the prototype, and the locomotives and rolling stock were more like caricatures than the real thing, with absurdly large trucks and disproportionate dimensions. But for a long time they were the most accessible toy trains around. Today an old Lionel set in good condition is worth quite a bit of money as a collector item. This isn't true of most other model trains, which lose value as better quality trains are developed.

If you model Lionel you're in a special part of model railroading called Classic Toy Trains, which even has its own magazine. Otherwise, if you're modeling 2-rail O scale you're in the main branch of model railroaders.

2 rail O scale has always been a minority scale, but as with the rest of the hobby it has gained in popularity in recent years. It is more expensive than HO, and availability is limited, but if you are interested in O you can look at O catalogues (Walther's offers one, and most train shops carry it) to see if the available equipment is sufficient for what you want.

HO scale (1:87) This has been the majority scale since shortly after its introduction in the late 1930s. No one knows exactly what percentage of modelers choose HO, but it's probably around 75%, and higher for first-timers. (There have been various surveys, but none of them have a truely random sample, so 75% is a rough averaging of published figures.)

If you choose HO you've got lots of company. Almost every prototype that has ever been has been modeled by some manufacturer in HO, and the most popular are available from several manufacturers. New releases come out in HO first, and then sometimes in other scales. Your selection of structures, scenic material, track, and books dwarfs all the other scales. All this availability also means the best price competition -- you'll pay less per item than any other scale except perhaps N. When you read articles in popular magazines that are allegedly for "all scales" you'll find that 80-90% of them are in HO.

N scale (1:160) N scale came out in the 1960s in answer to those who were frustrated with the space issue mentioned above. TT scale (1:120) had been invented previously, as a smaller alternative to HO, but it never really took off.

Early N scale equipment didn't look or run very well. There were even problems with consistent scale, and today some items labeled as N scale from other countries are actually 1:150 (Britain) or even larger (East Asia).

But by the early 1970s N was sufficiently improved that it began being taken seriously. Then in 1973 the N trak module standard was invented and showcased at its first convention. The idea of running 150 car trains on a model railroad was an instant hit, and N trak grew rapidly in popularity.

In 1978 a landmark series of articles in Model Railroader described how to build a portable version of the Clinchfield in N scale and this was hugely influential. Then in 1981 Bill and Wayne Reid started publishing their articles of their large, incredibly detailed N scale layout based on a Pennsylvania and Maryland prototype. N scale was now considered a serious scale and through the 1980s and 1990s Model Railroader made a point of promoting N scale in virtually every issue. (They no longer do this, probably because there are now two N scale-only magazines that are widely read).

MicroEngineering and Micro-Trains entered the N scale market, making much better looking equipment available, and as of today most HO scale manufacturers have followed suit. The old questions about N scale electronics have been addressed -- equipment built in this century runs as well as does HO scale equipment.

So, today, N scale is a distant #2 to HO, but is gaining steadily. Pricing is similar -- although it must be admitted that an N scale layout will cost more than the same size HO scale one because you'll probably buy more equipment. Availability is now very good in N scale, such that the most well known locomotives and equipment are available in both scales, but HO scale is still ahead both in terms of the more obscure prototypes and also in terms of the wider range of road names and numbers available.

N scale has the space advantage described earlier. In terms of the "size" criteria, well, this is where HO wins hands down. HO track and HO locos and rolling stock are much easier to work on than N scale equivalents due to their size. This is especially true of DCC decoder installs, but also of other general maintenance and installation tasks. A similar comment can be made about most other tasks that are affected by size, from de-coupling to reading numbers on the cars.

This isn't to say that smaller size is always a disadvantage. N scale is about 54% the size of HO in one dimension, but in 3 dimensions (i.e. volume) N scale is about 16% of the size of HO. This means that voltage requirements are far lower, as is weight, and both of these are to our advantage during construction.

Z scale (1:220) Märklin introduced Z scale to Europe in the 1970s. Why did they choose a scale only a bit smaller than N? Possibly because their 3-rail HO was already proprietary and they liked having a line of trains that didn't interoperate with anyone else.

Whatever the reason, Z scale sold sufficiently that Märklin introduced U.S. prototype equipment into the states in the early 1980s. It was not very realistic -- rails were ridiculously huge, couplers were almost half the length of the cars, wheels too big, etc. But it was promising. In 1983 the great layout designer John Armstrong wrote a tremendously well-thought out article on how to design a Z scale layout, and later it was included in a layout book. This, combined with the introduction of much more realistic Z scale items by Micro-Trains a few years later, made Z a viable scale in the U.S.

Today Micro-Trains is still the main supplier of U.S. Z scale. Z scalers often supplement by picking up European models and Americanize them for their layouts. DCC manufacturers have made Z scale decoders for over 10 years now, and newer Z scale locomotives are not difficult to convert to DCC -- all or almost all Z scale locomotives are diesel.

Z is most commonly chosen by those who have only very small space to work with. You can really get a nice layout into a small space with Z. However, recently the trade magazines have showcased a few very large Z scale layouts which are designed to really exploit the "space" advantage noted above. One that was recently featured was of a Swiss line and the use of Z allowed the modeler to duplicate how the monsterous Alps just dwarf the tiny trains that snake through them. If you are willing to select a road name and era that matches the equipment available in Z you can do some terrific modeling.

Settling on a choice of scale. So, if you were to walk into a large train shop and look at all the available scales, which would you choose?

You could find starter sets in all of the above scales, but the selection would vary greatly. At Caboose Hobbies there is one very long aisle (60 feet? 80 feet?) almost exclusively taken up with HO starter sets, from the cheap to the better quality. There is a good selection of N scale as well, but not so much of the other scales.

If you're thinking outdoors you'll take large scale. If size is your most important criteria, O or large scale is your likely choice. If space is the main factor, you'll be over at the Z area of the store.

But the vast majority of newcomers choose HO. N scale is in second place, but it's a distant second -- maybe 1/4th of the number of people who choose HO. So, if I knew nothing about you I'd have to suggest you choose HO simply because that's the default. But if you asked me why some people choose N, here's what I'd tell you.

Consider a typical HO 4x8 layout. Yes, you can squeeze the same layout in N scale in a space smaller than 3x5, and that's one advantage. But suppose you took that same HO layout plan and duplicated it in the same size for N. Instead of ridiculously tight 18" HO curves you'd have respectably broad 18" N scale curves -- that is, the trains would look a lot more realistic as they went around the layout. Instead of having to run pathetically short train consists of 8 or 10 cars you could run almost plausible consists of 16 or 20 N scale cars. Go outside the 4x8 and the advantages are even greater. Longer trains, wider curves, larger yards, all in the same space.

For example, suppose you wanted to run the classic passenger train, the California Zephyr. Kato makes a great model of this in HO and N. It's 11 cars long. With 3 locomotives pulling it is about 7' in N scale but closer to 14' in HO scale. In most room size layouts you can fit a couple nice 7' long stations in without having to make them go around a corner curve. You won't be able to do that with 14' stations in HO.

So that's my $.02 on the choice of scales. And I didn't try to hide it, but you can see from this write-up why I like N and large scale.