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I've had minimal exposure to S gauge but I've seen a friend's collection of misc postwar AF items. So my question is: was the standard track radius pretty much all 20" ?

 

I've toyed with the idea of maybe putting some O27 or Marx O-gauge cars on S-gauge wheelsets, for a small demo 2-rail S-gauge layout. Or maybe get a few cars of old AF. But if the smallest available curves are 20" radius, it actually takes more space than O27.

 

I've experimented with extreme curve radii in HO and N scale. I might do the same with flex-track in S-gauge if the cars could negotiate it without having to do additional modifications. I know wider curves look better for scale equipment, but I'm considering a small layout project.

 

Ideas appreciated ...

Last edited by Ace
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Originally Posted by Ace:

I've had minimal exposure to S gauge but I've seen a friend's collection of misc postwar AF items. So my question is: was the standard track radius pretty much all 20" ?

 

I've toyed with the idea of maybe putting some O27 or Marx O-gauge cars on S-gauge wheelsets, for a small demo 2-rail S-gauge layout. Or maybe get a few cars of old AF. But if the smallest available curves are 20" radius, it actually takes more space than O27.

 

I've experimented with extreme curve radii in HO and N scale. I might do the same with flex-track in S-gauge if the cars could negotiate it without having to do additional modifications. I know wider curves look better for scale equipment, but I'm considering a small layout project.

 

Ideas appreciated ...

Yep.  Unlike Lionel who offered O27, O31, O72 and later the O36 of Super O, A.C. Gilbert only offered one radius, the 20" radius for Flyer.  Ironically, it was cataloged as a 10" curve, referring to the overall length of the section end-to-end rather than the radius or diameter.

 

K-Line offered curves that made a 54" diameter circle.  I don't recall if that was measured from the center of the track or the outside of the rail.  Lionel offered the K-Line track for a brief time.

 

The former SHS offered 20"(early catalogs listed it as 21") 24" and 27" radius curves.  The turnouts matched the 20" radius curve.

 

American Models also sells 21", 24 and 27" radius curves.  Turnouts are listed as matching the 27" radius curve.

 

Lionel S FasTrack is 20" radius.  Turnouts are not available yet but will match the 20" radius curve.

 

Rusty

Originally Posted by ADCX Rob:
Originally Posted by Ace:

...But if the smallest available curves are 20" radius, it actually takes more space than O27...

I guess you haven't seen the "Magician" AC Gilbert make "S" fit more trackage into less space than "old stye" O gauge?

 

 

Ah, magic.  Smoke and mirrors.  Tomatoes vs. cherry tomatoes...

 

As long as ACG's comparing Flyer track to O72, yes.  Compare Flyer track against O31, no.

 

Such is advertizing...

 

Rusty

So my question is: was the standard track radius pretty much all 20”?

 

 

If you are talking about centerline radius the answer is about 19.125”.  There has been much debate about this topic over the years and it never seems to get settled.  A simple drawing or a bit of geometry will give you the answer.  I hope to insert a .pdf file that should explain the answer.

 

The SHS centerline was 18.55” as stated in S-Trains #46632 January 11, 2008.  You can see what happens with this radius in the first illustration, it results in a parallel track center to center measurement of 4.97”.  Close to 5”, but that’s not what original AM Flyer used.

 

The American Models turnout is a #4 that has a diverging angle of about 14.30448°.  It is cataloged as 27” radius, but one look at the picture and you can see it is not. -- http://www.americanmodels.com/misc/track.html  --  The 27” radius is not a continuous curve like you are used to with toy train switches.  You might what to Goggle NMRA Turnout Standards for more info.

 

Lionel S FasTrack is 20" radius.  Turnouts are not available yet but will match the 20" radius curve.

 

 I don’t know what it is cataloged as but a quick measure of a sample sent to me by Lionel yields a centerline radius of about 18.879”. 

 

It is interesting to note the differences between what a manufacturer catalogs and what the field measurements show.  One recent example is the  old SHS #155 rail long rumored to be code 125.  It actually measures out between .1375” to .138”, I call it .138".

 

Tom Stoltz

in Maine

Attachments

Originally Posted by Rusty Traque:
Originally Posted by Ace:

I've had minimal exposure to S gauge but I've seen a friend's collection of misc postwar AF items. So my question is: was the standard track radius pretty much all 20" ?

 

I've toyed with the idea of maybe putting some O27 or Marx O-gauge cars on S-gauge wheelsets, for a small demo 2-rail S-gauge layout. Or maybe get a few cars of old AF. But if the smallest available curves are 20" radius, it actually takes more space than O27.

 

I've experimented with extreme curve radii in HO and N scale. I might do the same with flex-track in S-gauge if the cars could negotiate it without having to do additional modifications. I know wider curves look better for scale equipment, but I'm considering a small layout project.

 

Ideas appreciated ...

Yep.  Unlike Lionel who offered O27, O31, O72 and later the O36 of Super O, A.C. Gilbert only offered one radius, the 20" radius for Flyer.  Ironically, it was cataloged as a 10" curve, referring to the overall length of the section end-to-end rather than the radius or diameter.

 

K-Line offered curves that made a 54" diameter circle.  I don't recall if that was measured from the center of the track or the outside of the rail.  Lionel offered the K-Line track for a brief time.

 

The former SHS offered 20"(early catalogs listed it as 21") 24" and 27" radius curves.  The turnouts matched the 20" radius curve.

 

American Models also sells 21", 24 and 27" radius curves.  Turnouts are listed as matching the 27" radius curve.

 

Lionel S FasTrack is 20" radius.  Turnouts are not available yet but will match the 20" radius curve.

 

Rusty

Rusty,

 

Do you know what happened to American S gauge from Classic Trains in CA?

 

I have a quantity of it and quite like it, downside to it was that it is/was quite expensive.

 

Neil

Originally Posted by Tom's Turnouts:

So my question is: was the standard track radius pretty much all 20”?

 

 

If you are talking about centerline radius the answer is about 19.125”.  There has been much debate about this topic over the years and it never seems to get settled.  A simple drawing or a bit of geometry will give you the answer.  I hope to insert a .pdf file that should explain the answer.

 

The SHS centerline was 18.55” as stated in S-Trains #46632 January 11, 2008.  You can see what happens with this radius in the first illustration, it results in a parallel track center to center measurement of 4.97”.  Close to 5”, but that’s not what original AM Flyer used.

 

The American Models turnout is a #4 that has a diverging angle of about 14.30448°.  It is cataloged as 27” radius, but one look at the picture and you can see it is not. -- http://www.americanmodels.com/misc/track.html  --  The 27” radius is not a continuous curve like you are used to with toy train switches.  You might what to Goggle NMRA Turnout Standards for more info.

 

Lionel S FasTrack is 20" radius.  Turnouts are not available yet but will match the 20" radius curve.

 

 I don’t know what it is cataloged as but a quick measure of a sample sent to me by Lionel yields a centerline radius of about 18.879”. 

 

It is interesting to note the differences between what a manufacturer catalogs and what the field measurements show.  One recent example is the  old SHS #155 rail long rumored to be code 125.  It actually measures out between .1375” to .138”, I call it .138".

 

Tom Stoltz

in Maine

Tom,

 

I can appreciate your exacting measurements of track radii. 

 

However, most folks will rely on the catalog listings.

 

Straight from the horse's catalogs:

 

Lionel 2012...

FasTrack

 

SHS 2000...

S-Trax 2000

 

SHS 2008...

S-Trax 2008

 

I can verify that the SHS small radius curve had no physical change in radius between 2000 and 2008, so there appears to be some room for interpretation.

 

Rusty

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Images (3)
  • S-Trax 2008
  • FasTrack
  • S-Trax 2000
Last edited by Rusty Traque

Thank you all for the feedback.

 

My next question is: what is the smallest flextrack radius feasible for reliable operation of typical small S-gauge 8-wheel freight cars, without having to modify the cars? I know that wider curves look better for scale equipment, but what I am considering is just a small minimum-size S-gauge demo layout, probably just an oval or figure-8. I would choose a suitably small loco, or possibly improvise my own 4-wheel boxcab power that would be happy on tight curves. I will probably abandon this idea if it can't be done in less space than O27.

I can appreciate your exacting measurements of track radii. 

 

Thanks Rusty, I wish I could take credit for the  dimensions, but they are the work of the computer, calipers and calculator.  I was just answering a question.

 

However, most folks will rely on the catalog listings.

 

That is exactly my last point.  The catalogs state one thing, reality is another.  I guess the advertisers say what makes for great promotion and as long as the trains run, what it actually is doesn’t matter.  That’s why there is so much confusion about AM Flyer radii.

 

I can verify that than SHS small radius curve had no physical change in radius between 2000 and 2008, so there appears to be some room for interpretation.

 

I didn’t say there was a change.  The radius I mentioned is straight from the owner of SHS.  Please check the reference. 

 

The Lionel catalog does indeed state a 20” radius, however they don’t tell you where they are taking their measurement from.  The 20” measurement appears to come from about the lower 1/3 of the outside slope on the roadbed.  The radius of the outside rail is about 19.328”.

 

So how much does it matter?  Well that’s up to you.  There is enough play in sectional track that you can ‘bend’ your circle to fit within the ranges mention here.  My curiosity is what was it designed to be?  I was quite surprised at the results for the AM Flyer radius.  Also if you are using a program like CADrail to design your layout, if you do use the cataloged dimension you will be in for some surprises.

 

Do you know what happened to American S gauge from Classic Trains in CA?

 

I believe they where caught up in the SandaKan downsizing.

 

Tom Stoltz

in Maine

 

 

 

 

Originally Posted by Tom's Turnouts:

 

However, most folks will rely on the catalog listings.

 

That is exactly my last point.  The catalogs state one thing, reality is another.  I guess the advertisers say what makes for great promotion and as long as the trains run, what it actually is doesn’t matter.  That’s why there is so much confusion about AM Flyer radii.

--------------------------

So how much does it matter?  Well that’s up to you.  There is enough play in sectional track that you can ‘bend’ your circle to fit within the ranges mention here.  My curiosity is what was it designed to be?  I was quite surprised at the results for the AM Flyer radius.  Also if you are using a program like CADrail to design your layout, if you do use the cataloged dimension you will be in for some surprises.

 


Tom Stoltz

in Maine

 

 

 

 

Well, the best I can come up with is that A.C. Gilbert measured track by total outside diameter and not radius, as did Lionel Corporation.  And I believe that includes the outside edges of the ties.

 

The only real indication I could find was at:

http://www.myflyertrains.org/A...6_catalog_page29.htm

 

...which indicates a circle of Gilbert S Gauge track required a 40"x40" space.

 

It seems Gilbert chose 40" because that what was used in their O Gauge line from 1938:

http://www.myflyertrains.org/A...F_catalog_page24.htm

 

...Where Gilbert also offers justification for the choice of diameter. 

 

In the imperfect world of the past, folks buying train sets for their kids were concerned if the track would fit somewhere, rather than the exact radius of a curve.  They could easily identify the space available on the dining room table, under the bed or around the Christmas tree and not worry about silly little things like radius.  I know when my folks bought our first Lionel set for my older brother, they weren't worried about track radius.  They just wanted something to keep him occupied and inside while he was sick.

 

Even later, all we were worried about was would "the Lionel" fit on a 4'x8' sheet of plywood.

 

And I myself didn't worry about this thing called radius until I got into HO at the ripe old age of 11. 

 

Curses!!! I was learning about geometry and didn't even know it... 

 

I would agree, it would be wonderful if all S gauge track was marketed as measured from the center of the track as in the "scale world."

 

But in most S cases: Tradition trumps reality.

 

Rusty

I would agree, it would be wonderful if all S gauge track was marketed as measured from the center of the track as in the "scale world."

 

But in most S cases: Tradition trumps reality.

 

 

I fully agree with you, Rusty.  That’s why I think we need to be more careful in what we pass on to other people asking questions.  The norm now is to the centerline and as you say the old catalog states a circle will fit within a 40”x 40” square, but it does not mention the radius of the track.  I don’t think one can assume a 20” radius for track that fits a 40” square.

 

The full size guys have always measured track by centerlines.  My guess is so has model railroading.  I am disappointed by the companies that have misrepresented their products claiming they are something they are not.  Even on the S-scale SIG site there is still  an article that claims SHS rail is .131”.  What’s the point?  Isn’t better just to measure the rail and state what it really is the to perpetuate a myth?

 

Most of the time I don’t get it,

 

Tom Stoltz

in Maine

I've just seen a reference to American Flyer "Pikemaster" track that had 15" radius. I read that it was somewhat fragile and apparently had no enduring popularity. If I was maybe going to build a small demo S-scale pike I would probably want to use a smaller radius like that instead of the usual 20" radius. I'm wondering what experience you guys here have had with 15" radius track for S scale and the limitations on locos and rolling stock.

 

I'm also wondering, what is the smallest flextrack radius feasible for reliable operation of typical small S-gauge 8-wheel freight cars, without having to modify the cars? I know that wider curves look better for scale equipment, but what I am considering is just a small minimum-size S-gauge demo layout, probably just an oval or figure-8. I would choose a suitably small loco, or possibly improvise my own 4-wheel boxcab power that would be happy on tight curves.

 

I've done minimum radius trials for a variety of HO and N gauge trains, but I don't have any S gauge rolling stock so far.

Last edited by Ace
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