O27 scale is something of a misnomer. If you’re looking for scale fidelity, you won’t find a lot of it in O27, regardless of manufacturer. But there are still some general guidelines you can follow.
O27 is the designation for entry level O gauge trains that are smaller and less expensive, though capable of running on the same track. But their scale can be confusing, even for experienced hobbyists.
O27 scale vs gauge
There’s no official standard for O27, and that’s one reason it’s confusing. O27 trains originated in the 1930s, and all it meant was the circle of track was 27 inches in diameter, and the train was small enough it could navigate it without derailing. O27 is a far sharper curve than you see in real life, so the trains require some selective compression in order to fit.
Generally what worked in the 1930s was train cars around 7.5 inches in length. But no one dared call it scale. The car bodies were 7.5 inches long, which works out to about 1:64 scale, but they looked bigger than that, because they used the same running gear as their larger trains. The wheels on some of those 1930s trains were more appropriate for 1:32 or even 1:28 scale. They were oversized even for 1:48.
The cheapest O27 sets were even smaller than that, sometimes with 6-inch bodies. The proportions are so out of whack you can’t even assign a scale to them easily. I like them, but they aren’t scale models.
Manufacturers generally called it O27 gauge, not O27 scale. And the gauge referred to the track. Gauge can mean two things: the distance between the rails, or the thickness of the metal. The distance between the rails is the same in O27 and regular O gauge, but the track is made of thinner, lighter gauge metal.
Evolution of O27 scale over the years
After AC Gilbert bought out American Flyer, he decided toy trains should be more realistic than what other manufacturers had been offering. He phased out the older toy lines and introduced a new design that was 1:64 scale, all the way down to the trucks. These were true 1:64 scale trains, just running on O gauge track, which was too wide for 1:64 scale. Some hobbyists, notably the late Thor Sheil, credit Gilbert with inventing O27. But really he just took the next logical step from what the company he bought was already doing.
And while the new 1:64 Flyer train cars ran happily on O27 track, anything but the smallest Gilbert locomotives failed miserably on O27 track. Gilbert shipped it with 40-inch diameter track, and that’s what he intended those trains to run on. I’ve been able to coax some prewar Gilbert American Flyer locomotives to run on smaller track, but anything smaller than O34 seems to be pushing it.
Marx took a cue from Gilbert and released a line of 1:64 scale cars, along with its 999 locomotive that did run happily on O27 track.
After World War II, Gilbert finished the transition, switching to S gauge, which is correct for 1:64 scale. Marx continued manufacturing its 1:64-on-o-gauge trains for several more years.
Lionel was in the O27 game too, but came in later, dragged in by the Great Depression. But Lionel generally put trucks appropriate for 1:48 scale on 7.5-inch bodies, so their cars appeared tall, but not grotesquely so.
Postwar Lionel and Marx O27
After World War II, both Marx and Lionel transitioned to plastic. Lionel introduced new diecast trucks and knuckle couplers, which it used on both its O27 and full-size O gauge cars. The Lionel bodies were still generally very close to 1:64 scale. Close enough, in fact, that you can swap the Lionel trucks for American Flyer trucks and run them with S gauge and they fit right in.
Marx followed Lionel’s lead, introducing running gear that was sized very much like Lionel’s. Marx’s cheapest sets were also 1:64 scale, sometimes on the 1:64 scale trucks, but increasingly on the taller Lionel-like trucks. Marx’s more expensive sets were closer to 1:60 scale. Undersized still, but slightly larger.
Modern O27 scale
Today, O27 means pretty much anything smaller than 1:48 scale. That includes a lot of Lionel postwar designs, such as the 6464 boxcars, that weren’t marketed as O27 in their heyday. These larger cars were 1:55 scale or so, noticeably larger than postwar O27 was. The difference is most noticeable in boxcars, as gondolas and flatcars can vary somewhat in length and height anyway.
What scale of accessories to use with O27
The debate with O27 is always what’s the proper scale of buildings and accessories like figures to use with them. The magazines generally recommend using 1:43 vehicles and 1:48 buildings and figures, the logic being that if you buy (I won’t say upgrade to) larger 1:48 scale trains later, you’ll be ready. And since the trucks tend to be oversized, that combination doesn’t look bad.
But 1:64 vehicles and figures don’t look bad either. Plasticville buildings are sized so they can pass for 1:64 or 1:48 or anything in between, and many prewar tin buildings are 1:64 or even smaller. I’ve taken that approach for the last 15 years or so. Sure, it’s contrarian, but I like how it looks, and it’s something different. When I pick up either of the magazines and look at their featured layouts, I always see the same buildings and vehicles and figures.