Has anyone else seen, or had (have), Shinohara curved turnouts with 24" outer radius and 22" inner radius,…code 100??
I have one right hand one that appears to be that size. I laid a Ribbonrail 24" gauge in the outer curve, and it sure fits well.
I have a potential use for a couple of these,…one left, one right at the moment.
Brian,
Most curved turnout have 4-6" of seperation. Those Atlas ‘Customline Supreme’ turnouts are 22" and 18" radius. A 2" seperation would result in a very long turnout! You could custom build one…
Jim
Yes, I felt a distrubance in the schwartz when I saw the “Shinohara Curved Turnout 24/22, Code 100” in the title. The assumptions of the inner radius appear to be false.
As Jim noted, the separation in Shinohara curved turnouts is nominally listed as 4 inches so if the outer is 24", the inner is 20" nominal, but as many have noted in real life, the inner is closer to 6" less than the outer so the real radius’s are probably more like 24/18.
Jim, I thought if anyone had ever run across these, it might have been you.
I’ll take some photos of the one I have and show you how I came up with those curve dimensions.
The consensus amongst modelers experienced with these turnouts is that the outer radius is as advertised but the inner radius is listed as 2 inches generous. There is closer to a 6 inch drop between outer and inner, often which causes problems in layout planning because the inner radius discrepency causes curves to be much tighter than hoped for.
Of course, stepping up in turnout number to get the inner radius where it needs to be forces the outer radius to often become too broad. And there you have it.
As another has mentioned, if the drop wasn’t very severe, the frog itself would be really long. The dead spot beyond the frog would have to be even longer to avoid shorting where the rails came together.
The only Shinohara or Walthers curved turnouts I have personal experience with are the #8 curved as I wanted the largest radius I could find.
Are you saying by laying ribbon rail into the inner radius, that is how you came up with 22"? If so does that take into account the effective inner radius from end to end?
Anyway, if you are happy with those curved turnouts and you can run your trains through them, then to gain our approval here. You need to satisfy yourself ultimately.
the greater the difference in radii, the closure the frog is to the points
the frog for a properly laid out 22/24" curved turnout is 17" lateral inches from the points. See other diagrams for comparison
So grec, is it possible to have a #6 curved turnout with an outer radius of 24" to have an inner radius of 22"? Or would the inner radius have to be sharper on a #6 frog to clear the outer radus, and by how much sharper?
based on geometry, it looks like a curved turnout with an outer radius of 24" and a #6 frog would have a 16" inner radius.
but i don’t think curved turnout frog numbers are important with respect to curved turnouts, the radii are. In straight turnouts, the frog number suggests the closure rail radius and whether a locomotive can handle it.
Brian replied on this subject in another forum that he physically measured the inner radius at 18", which follows the pattern with the other curved turnouts. May have measured with a ribbon rail template.
apologize for my mistake
That Shinohara measured out to be 24" outer, 18" inner.
I’ll post some photos of my experiments,…(likely tomorrow morning due to a Thankgiving feast this late afternoon)
this diagram shows how by offsetting the centers of the curves, the curves intersect at the angle of a #6 frog and the radius of the diverging rails are 18". The closure rail radius of the inner curve would be < 18" (~0.5").
Have no idea where the location of the frog is on a commercial turnout
VERY interesting sketches Gregc, thanks so much.
I need to come back for another look a little later today.
Shinohara, code100 Curved Turnout
As I have mentioned above I was incorrect when I first assumed it was a 24/22 turnout.
So first I took my RibbonRail gauge and inserted in the outer rail curve,…
Next I went about determining that inner rail radius, and I tried several different methods…
First laid out over my drawn curves
Second, with a piece of 18" Atlas sectional track laid over the inner radius…
Damn close to 18" inner radius I would say.
So I pronounce the Shinohara as a 24/18, which seems to match their code 83 offerings as well.
Something rather strange came up when I tried this little experiment. I laid a paper template of the Peco dbl-curve over the Shinohara dbl curve in such a manner as to align their inner radii. Seeing as how the outer radius of the Shinohara is definitely larger than that of the Peco, its strange that it does NOT appear that way in this photo??
I was playing around with those dbl-curved turnouts I have and I’ve come to a couple of conclusions:
The Roco 24/18 are rather well made, and they have an isolated metal frog that could be made an electrofrog.
The Peco ties between the diverging tracks could be cut and spread slightly such that they became an honest 22/18 or perhaps a 23/19.?
As I was fooling around with one of my Peco dbl-curves today I think I discovered that same thing,…it appears to curve a bit more as it diverges.
And a thought occurred to me, how about cutting some of those ties between the 2 diverging tracks and make them a little less severe curves? Perhaps we could make these turnouts into a true 22/18,…or even a 23/19 ??
…from another forum…
The difference might be the tiny ‘straight’ section (see yellow below) on the outside track of the Peco. That makes the “effective” radius longer, even though the “governing” radius is less.
Put a straight edge on the real physical one to verify this.
In fact I think that short straight section extends back to the ‘entrance’ of that turnout ?
Straight Track Section on Peco ST Curved Turnout
A few days ago I had run a little experiment where I had connected some Atlas sectional track pieces to both ends of that Peco curved turnout,…a 22" piece on 2 ends, and an 18" piece on the diverging inner radius. I ran some cars (hand pushed) over this combo to see how well they negotiated it,…all did well.
But I did notice a slight wiggle in the cars as they ran over the ‘entrance’ to the curved turnout. Now I see why,…that short section of straight track that exist at the entrance.
3 Brands Compared
Here are 3 brands of ‘small radius’ curved turnouts lined up via their frog points, Shinohara 24/18, Roco 22/18, Peco (approx 22/18)
I did notice that the outer rails of the point ends of the Shinohara and the Roco turnouts were curved radius. The Peco rail was a straight line in that area.