Model Train Journal

Confused about size variances in O gauge? Then look here!
https://www.modeltrainforum.com/threads ... post-43540

There are only two scales in O-gauge, 1:48 and smaller.

A bit more specific:

Back in late 40's, possibly early 50's, when folks were asking this question, some rag, I think it was RMC or a predecessor, found and measured every piece of 3-rail he could find.
The reported average was 1:52 or 1:53.






;

I wish I had read that. More data is good.

Lionel LLC has this to say about O-Gauge scale:

Lionel O-Gauge sets are electric sets that are approximately 1:48 scale and are what most people envision when the think about Lionel. O-Gauge is divided into two categories: Traditional O-Gauge and O Scale

Traditional O-Gauge
Approximate scale proportions

O Scale
Larger than Traditional O-gauge products since they are more true to 1:48 scale proportions.

The problem with that thread is that it continues the confusion of "Scale" and "Gauge". Most modelers know what scale means and differentiate it from gauge. Some of the manufacturers and many collectors do not. in O Scale, you can ON3, ON30, ON2 and others. These are all O Scale, but the track gauge in each case is different. ON3 means O scale models that run on track that scaled to 3 ft, ON30 generally uses track the same gauge as HO to represent 30 inch gauge but the equipment is also still O Scale. All the narrow gauge equipment is generally smaller that "Standard" gauge which to an O scale modeler means O gauge track.

For example, what is the meaning of "O-27 Gauge" vs "O Scale". The thread uses the terms to mean two different sizes of equipment. But the rub is they both run on track that has the SAME GAUGE. If you use the definition of Gauge as the track gauge, which is what I think, then all the sizes of the equipment are the same, and they are all O-Gauge ie. they run on the same track gauge regardless of size.

Most of the products made to run on 0-27 track (Same gauge, 27 inch diameter curves), is designed and built smaller than O Scale so it can negociate the curves. Most O scale models require wider curves.

I've got a circle of 42-inch diameter O-27 track...what is that?

The author of the link is kind of wet and doesn't know his O scale history (or arithmetic for that matter) all that well. For an American track gauge of 4'-8 1/2", 1/48 is NOT the correct scale for 1 1/4" O gauge track. 1/45 IS correct for O gauge track. Formerly known as 17/64"/ft scale. Quite popular in the 30's and 40's. A track gauge of 1.17" (formerly known as proto 48) is correct for 1/48. The NMRA standardized on 1/48 because it's an easier number to scale down. But then of course because MTH claimed 1/48 is correct for O gauge track, then it's correct. Obviously the author of the link drank too much of that Kool Aid.

prrjim wrote:The problem with that thread is that it continues the confusion of "Scale" and "Gauge"

BINGO. Nor do they understand the difference between gauge and diameter. And then there's "standard scale" Who the hell dreamed that up???