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On3 vs On30: Narrow gauge O scale trains

Narrow gauge railroading is almost always confusing, and On3 vs On30 is no exception. They sound similar, and they are, though there are some differences.

Narrow gauge has a following among hobbyists who want to be able to model small areas accurately. Most basements don’t have adequate space to model a big-name railroad with any kind of scale accuracy. But it’s possible to model a small narrow gauge operation in a small space. Narrow gauge O scale trains are a great compromise for people who want big trains in a small space.

On3 vs On30 nomenclature explained

On3 vs On30

This is an On30 layout. The trains and track are smaller than what you see on more common large trains such as those run by Union Pacific, BNSF, Norfolk Southern, CSX, or Kansas City Southern. Photo credit: Zabdiel/Flickr

First things first: Let’s explain what these letters and numbers mean.

O refers to the scale. Both of them represent 1:48 scale models of trains that existed in the real world.

N refers to narrow gauge. Narrow gauge just means train track that was closer together than 4 feet, 8.5 inches, which we call standard gauge. Standard gauge is what the big railroads like Union Pacific, BNSF, Norfolk Southern, CSX, and Kansas City Southern use. Small railroad operations, especially ones that don’t have the benefit of running on nice, flat ground, used narrow gauge track to help deal with the harsher environment.

3 or 30 refers to the distance between the rails. “3” means three feet. “30” means 30 inches. You kind of have to make an educated guess with these numbers. It wouldn’t make sense to put rails 30 feet apart, and it wouldn’t make sense to put them three inches apart either.

On3 vs On30: Realism vs convenience

In the United States, a 30-inch track gauge was relatively rare. Three feet was much more common. On30 exists because HO scale track happens to be 32 inches wide in O scale, so if you round down, you can use common HO track and mechanisms to model narrow gauge O scale.

Some people think this is great. Some people think it’s not so great. I look at it this way: Standard gauge O scale track is three and a half scale inches too wide. Looking at it that way, narrow gauge track being four inches too narrow isn’t a big deal. It’s close, and if you’re not blessed with the eyesight of Ted Williams, you probably won’t notice.

If you’re a stickler for detail and don’t mind building most of your own stuff, go for On3. It just so happens that On3 track is the same gauge as American OO gauge track, but HO scale track is much more common. If you’re fine with close enough and want a wide selection of available off-the-shelf stuff, go with On30.

Whichever you choose, it’s likely you’ll need a pickup truck or two to complete your railroad. You’ll be surprised how many true 1:48 scale vehicles are available.

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