EZ Track Curved turnouts

[ryeguyisme]

Hey bachmann,

How about some curved nickel silver turnouts? Like with 33 and 35 inch radius

[Joe Satnik]

rgim,

If you are just trying to make an early cutoff configuration,

then widen the outside route and the single semi-circle end of the oval with fitter straights

(halfway around each end's curve)

so that the divergent route of a #6 turnout will fit on the inside route.

If you are trying to "drop in" a turnout on a curve,

(i.e., replace a curve with the divergent route of a turnout) then,

yes, you would need the wider curved turnouts you are asking for, but with little or no "offset".   

Note that the Remote (18"R) Switch has an 1.5" offset

(the curved divergent route starts 1.5" up the straight from the points end)

that has to be accounted for in the layout design when trying to "drop in"

a turnout on a curve. 

Here's your turnout geometry final exam:

Let's say you are the design engineer on the two new curved turnouts that you want. 

What specs (turnout dimensions) will you be asking for?

Explain your choices.

What effect does the track bed width have on your design?

What effect do the points end rail joiners have on the offset?

Hope this helps.

Sincerely,

Joe Satnik 

     



 

[jward]

ok since you asked about design here's mine.....

I would like a return of the old 18r-22r curved switch. the design for this one was pretty simple: standard 1.5" straight before the points, 30 degree arc of both the 18r and 22r curves. with ez track you may have to lengthen the arc to 45 degrees to compensate for the width of the roadbed. 45 degrees also has the added advantage of being able to be made from standard 18r and 22r sections, so no additional track pieces have to be made. the basic geometry from points to frog would be copied from the old 18-22 switches made in the 1970s by various companies, they were pretty much interchangeable. tolerances in the flangeways and frog would be tightened up to meet nmra specs, and the frog would be metal so it could be powered is the user desired.

as such, this switch would be a drop in replacement for standard track sections in the way the 18r "standard" switches are now.

[Len]

I'm with Jeff. I really miss those old 18/22 curved turnouts. Real space savers in a lot of situations.

Len

[Joe Satnik]

Dear All,

I read the original post too quickly, it seems, to catch that rgim was asking for a double-curve turnout.   

My (overly) long reply was for two separate turnouts, each with a straight route and curved divergent route. 

A double-curve turnout's main advantage is, as already stated, saving space.

A single-curve turnout also saves space (over a numbered turnout), but not as much as the double. 

Hope this helps. 

Sincerely,

Joe Satnik



 

[Bob_B]

Hey bachmann,

How about some curved nickel silver turnouts? Like with 33 and 35 inch radius

Yes please and in DCC as well.
While you're at it how about larger straight turnouts (DCC) as well.

[Joe Satnik]

Dear All,

Here is an AnyRail drawing of the 33.25" and 35.5" radius early cutoff configurations:



79" table width,

75" table width using only smaller 33.25" radius.   

#6 turnouts.

2" straight fitters.

Hope this helps. 

Sincerely,

Joe Satnik

 

[ryeguyisme]

yes, I was referring to a double curve turnout. It saves a lot of space especially when you're trying to squeeze in as much possible in a 12 by 7.5 with a minimum radius of 30 inches

[Joe Satnik]

Hmm,

A double-curved 33-35 turnout would be monstrous.

You could hand lay them, but there would be many inches of curved rail

before you even get to the frog,

let alone clear the ties or get to separated roadbed.

http://www.handlaidtrack.com/

You would want to make sure that a right and left can form a curved crossover.

Hope this helps. 

Sincerely,

Joe Satnik

[ryeguyisme]

Or perhaps a 30 50 #6, which isn't as huge but keeps the radius to a 30 minimum

[Joe Satnik]

Dear All,

I ran the math on the double curve turnout,

which is the "Law of Cosines" for you that fondly remember your high school Trig.

The 2 radii, plus the separation width, is put into an Excel spreadsheet,

which gives the "degrees of turn" and the arc length of the outside of the turnout.

For the 33.25" and 33.5" radii,

Frog angle = 2.65 degrees,

Frog number = 21

Degrees of turn at frog:  44

Degrees of turn at frog rail separation: 47

Degrees of turn at tie separation: 58, outside arc length 37"

Degrees of turn at (narrow) top of roadbed separation: 66, outside arc length 42"

Degrees of turn at (wide) bottom of roadbed separation: 80, outside arc length 51"

So, somewhere between a 42" and 51" long turnout. 

Almost a 90 degree turn.

Somewhat impractical to make, ship, and keep from breaking.   

Perhaps in 2 pieces?


For the 30" and 50" radii,

Frog angle = 7.5 degrees,

Frog number = 7.6

Degrees of turn at frog:  11.5

Degrees of turn at frog rail separation: 12.2

Degrees of turn at tie separation: 15, outside arc length 13.2"

Degrees of turn at (narrow) top of roadbed separation: 16.7, outside arc length 14.8"

Degrees of turn at (wide) bottom of roadbed separation: 19.7, outside arc length 17.6"

So, somewhere between a 14.8" and 17.6" long turnout.

Hope this helps.

Sincerely,

Joe Satnik

 

[Len]

Joe,

What about the 'classic' 18"/22" radius combo that started this whole thread??

Len

[Joe Satnik]

Hmm,

I Just learned something:  

Crossovers made up of L and R double curve turnouts have no "S" curve, which is part of any low numbered straight crossover...



For the 18" and 22" radii double curve turnout,

Frog angle = 6.3 degrees,

Frog number = 9

Degrees of turn at frog:  30.4

Degrees of turn at frog rail separation: 32.4

Degrees of turn at tie separation: 40.1, outside arc length 15.8"

Degrees of turn at (narrow) top of roadbed separation: 45, outside arc length 17.8"

Degrees of turn at (wide) bottom of roadbed separation: 53.9, outside arc length 21.6"

So, somewhere between a 17.8" and 21.6" long turnout.

No offset before points on my calculations.  (The points and both curves start at "zero".)

There are more than a few manufacturers of double curve turnouts (non-roadbed code 100) out there.  

Not necessarily the perfect match to HO E-Z Track, but perhaps something you could work with.  

To find them, just browse all the HO track libraries on the AnyRail track CAD program.  

Hope this helps.

Sincerely,

Joe Satnik

Edit: Add demo photo.

[Doneldon]

Joe-

What about the clearance between parallel tracks which are so close together and on a curve?

                                                                                                                                 -- D

[Joe Satnik]

Don,

You would choose the inside and outside curve radii with enough difference between the two to avoid that.

http://nmra.org/standards/sandrp/s-8.html

Close radii dual curve turnouts are impossibly large, as in the 33.25"R-35.5"R demo photo of my last post,

and its details in the post previous to that in this thread.

Hope this helps. 

Sincerely,

Joe Satnik