O gauge/O scale

Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here)

RailroadBookstore.com - An online railroad bookstore featuring a curated selection of new and used railroad books. Railroad pictorials, railroad history, steam locomotives, passenger trains, modern railroading. Hundreds of titles available, most at discount prices! We also have a video and children's book section.

ModelRailroadBookstore.com - An online model railroad bookstore featuring a curated selection of new and used books. Layout design, track plans, scenery and structure building, wiring, DCC, Tinplate, Toy Trains, Price Guides and more.


Active Member
I've been looking at Lionel/MTH vs Williams models recently. They don't seem to be the same 'scale.' Are Williams 3 rail 1/4 scale and Lionel/MTH 17/64s? Williams seem much large than the Lionel/MTH versions of things.

Thanks in advance.


AKA Gomez Addams
Staff member
O has almost as many subscales as G scale. There is O gauge, and O scale, then there is O42, and O31, and O27. Then there is Proto 48, which is true O scale. The Lionel O will not go around the smaller radius. FYI, true O scale is 1:48.


Well-Known Member
In modern O gauge there are basically 2 scales
Standard O (Lionel) or sometimes called full scale O (Williams by Bachmann, and others)
Traditional O (Lionel) sometimes called semi-scale O (Williams by Bachmann, and others)

O27 refers to Traditional scale locomotives and rolling stock that were designed to be used with Lionel's old tubular O27 track. It will run on Lionel's new Fastrack or any modern 3 rail O gauge track. These are usually low cost because they were designed for the toy train market. I really like some of these cars!

O31, O36. O48, O60, O72 & O84 are the curves available for Lionel Fastrack. O31 makes a 31" circle measured from the Center rail, O36 a 36" circle measured from the center rail and so on...

O42 could refer to the minimum curve a locomotive or rolling stock could operate on.

All Locomotives and rolling stock are rated for minimum curve very similar to HO and other scales.

Standard O has become the high end, usually very detailed. Standard O is larger then Traditional O

Traditional O is what most Lionel Christmas trains and other Ready to run sets come in. Most modern traditional O is rated at O31 and most ready to run sets come with O36 track.

Standard O was first introduced by Lionel in the 1970s and is more true to 1:48 scale. Before the introduction of Standard O all Lionel and many other O gauge manufactures trains were what we now call Traditional O hence the name, Traditional O.
Last edited by a moderator:


Well-Known Member
Gauge vs. Scale
Gauge refers to track size. Scale, on the other hand, measures the size relationship between a model and its real-world prototype. For example, a Lionel locomotive that is 1/48th the size of the real thing is called 1/48th or 1:48 scale. (As it happens, O gauge trains are 1/48th scale.) Sometimes the terms "gauge" and "scale" are used interchangeably even though, technically, they're different.
Cut and pasted from Lionel.com



Active Member

Thanks for the info. I have some understanding regarding 'gauge and scale.' My collection of O stuff dates from the 60's and 70's, although I just bought a Williams EP5 in PRR, last year. The Railking F units I bought about 10 years ago, seem to go with the older Lionel stuff, in terms of size.



Well-Known Member
Hey Carl,

I am glad to be of service and I am always happy to talk to another O gauge railroader. There are not many of us 3 rail modelers on here, but this forum has some great people in all scales on it and I enjoy it very much.

Those Williams are from what I hear very good locomotives. I know even less about MTH but I have heard good things about them too.

Other then Lionel I have only 1 locomotive, a K-Line MP15, its a very dependable good runner too.

I picked up a new Lionel SD60 and when I get a picture of it I will post it, right now it is still in the box. If you have time I would like to see some pictures of your trains too.

You are very welcome and I have enjoyed talking you.

ModelRailroadForums.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com