Model Railroading > O-Gauge Curve Radii (O27, O31, etc)

I know very little about O-Gauge trains, however a co-worker today was telling me about his Lionel loop of track he set up around his wife's Christmas Village display in her home. Anyway, he's excited about it and is considering ordering other sets. He keeps seeing O23, O27, O31, and O36 references, seemingly regarding curve radii.

So, what exactly do those mean, and is the lower the number mean the curve has a tighter radius (or is it the other way)? He obviously doesn't want to buy any trains that won't clear his curves!

Thanks for any info!

-Tom

It's the radius of the curve. O-27 is the tightest. The others are larger. O-36 won't run on O-27 but you can run 27 rated on the larger curves. I found this out the hard way when I puchased some articulated wells for O gauge. Had to do some track work

Posted from Android

Thank you, that answers my question!

-Tom

NSDTK Wrote:
-------------------------------------------------------
> It's the radius of the curve. O-27 is the
> tightest. The others are larger. O-36 won't run on
> O-27 but you can run 27 rated on the larger
> curves. I found this out the hard way when I
> puchased some articulated wells for O gauge. Had
> to do some track work
>
> Posted from Android


The radius is approximately 1/2 the number designation - The number represents the size of a complete circle of curved tracks.

LarryDoyle Wrote:
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> The radius is approximately 1/2 the number
> designation - The number represents the size of a
> complete circle of curved tracks.


In other words, the O-number is the track circle diameter, rarther than its radius.

Art House

Get yourself an issue of the "CLASSIC TOY TRAINS" January 2015. wag216

Id forgotten that. In Ho its radius. In O it's more of a diameter

LarryDoyle Wrote:
-------------------------------------------------------
> NSDTK Wrote:
> --------------------------------------------------
> -----
> > It's the radius of the curve. O-27 is the
> > tightest. The others are larger. O-36 won't run
> on
> > O-27 but you can run 27 rated on the larger
> > curves. I found this out the hard way when I
> > puchased some articulated wells for O gauge.
> Had
> > to do some track work
> >
> > Posted from Android
>
>
> The radius is approximately 1/2 the number
> designation - The number represents the size of a
> complete circle of curved tracks.

Diameter in what UNITS?

Kimball Wrote:
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> Diameter in what UNITS?

Inches

The use of diameter is a unique designation of "tinplate" models, such as Lionel and others following their standards. All other modeling in US uses radius.

Interestingly, on the prototype (real railroads), virtually none except streetcar lines used either radius or diameter. Instead, they used a system which designated the amount of deflection in the track centerline in a 100 foot chord along the curve, measured in degrees of a circle. A 1 degree curve 100 feet long deflected the route by 1 degree, and was equivalent to a radius of 5728 feet. A 2 degree curved deflected 2 degrees, and had a radius of 2864 feet, etc.

-John

---

Go to:

www.lionel.com

and they will have any information which you didn't obtain from the other folks answering this thread.

DaleR