How do you determine the frog # of a curved turnout? If I had a turnout with a 27 inch outer radius and a 23 inch inner radius what would be the frog #?
Thanks
Bob D
Bob D As long as you surface as many times as you dive you`ll be alive to read these posts.
In the Walthers code 83, 20/24 is a 6.5 and 24/28 is a 7.
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Thanks Carl but I`d still like to know the math of the answer. I`m talking C100 but I don`t see where the code matters.
submanI`d still like to know the math of the answer
That's definately over my head.
We can then formulate the concept of the angle between two curves by considering the angle between the two tangent vectors. If two curves, parametrized by f1 and f2 intersect at some point, which means that
the angle between these two curves at c is the angle between the tangent vectors f1′(s) and f2′(t) is given by
carl425 subman I`d still like to know the math of the answer That's definately over my head. Angle between curves We can then formulate the concept of the angle between two curves by considering the angle between the two tangent vectors. If two curves, parametrized by f1 and f2 intersect at some point, which means that f1(s)=f2(t)=c, the angle between these two curves at c is the angle between the tangent vectors f1′(s) and f2′(t) is given by
subman I`d still like to know the math of the answer
Yea, we did this stuff back in 3rd grade!
-Bob
Life is what happens while you are making other plans!
farrellaa carl425 subman I`d still like to know the math of the answer That's definately over my head. Angle between curves We can then formulate the concept of the angle between two curves by considering the angle between the two tangent vectors. If two curves, parametrized by f1 and f2 intersect at some point, which means that f1(s)=f2(t)=c, the angle between these two curves at c is the angle between the tangent vectors f1′(s) and f2′(t) is given by Yea, we did this stuff back in 3rd grade! -Bob
Bob, Your school must have been sort a behind the times, we figured this easy stuff out in Kindergarden, where I lived!
NP 2626 "Northern Pacific, really terrific"
Northern Pacific Railway Historical Association: http://www.nprha.org/
NP2626 farrellaa carl425 subman I`d still like to know the math of the answer That's definately over my head. Angle between curves We can then formulate the concept of the angle between two curves by considering the angle between the two tangent vectors. If two curves, parametrized by f1 and f2 intersect at some point, which means that f1(s)=f2(t)=c, the angle between these two curves at c is the angle between the tangent vectors f1′(s) and f2′(t) is given by Yea, we did this stuff back in 3rd grade! -Bob Bob, Your school must have been sort a behind the times, we figured this easy stuff out in Kindergarden, where I lived!
When I fabricate a curved turnout I lay both routes with bent flex track, mark the tie lines and assemble the rails to the curves. The only way I will ever know the frog number is if I pull it up and straighten it out. (One, connecting two radii I now disremember, turned out to be an 8.375.)
Actually, as long as your rolling stock can run through both routes without a hiccup, the frog number is irrelevant.
Chuck (Modeling Central Japan in September, 1964 - on handlaid specialwork)
submanI`d still like to know the math of the answer.
this is what I think
the first step is to locate the point of intersection.
y = (rad1^2 - rad0^2 - y1^2 + y0^2) / ((2 * (y0 - y1))
where rad0 is the radius of the outer rail of the smaller radii and rad1 the radius of the inner rail of the larger radius. Y0 and y1 are the locations of the radii centers. (I assume the x centers are the same value (0), see figure below).
the 2nd step is to determine the angles between the point of intersection and the radii centers (yellow lines below). The difference between these angles is the same as the difference between the angles of the tangents of the curved rails at the point of intersection.
the frog number is most accurately determined by dividing the cosine of half the angle by twice the sine of half the angle.
the following image illustrates values for various curved turnouts. The top row is for two curves 2" apart and the bottom for curves 4" apart. The larger radius curve is in green and the other curve in red. Yellow lines identify the angles between the curve centers and points of intersection. The curve radii are indicated at the base of the yellow lines. The frog number is on top.
i don't get the same values carl425 say the Walthers Catalog indicates
edit: updated drawing with corrected frog number calculation (still appears high)
greg - Philadelphia & Reading / Reading
BTW the actual frog (where the rails cross) is made of very very short sections of straight track, so it doesn't matter if the turnout is a conventional turnout or a curved turnout. The frog remains the same.
wjstixThe frog remains the same.
Isn't that a Led Zeppelin song?
On Walthers/Shinohara Code 83 curved turnouts, the rails are curved through the frog.
Dante
carl425 wjstix The frog remains the same.
wjstix The frog remains the same.
Rich
Alton Junction