USAT & Aristo-Craft #6 Switches (points)

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funandtrains

funandtrains

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#1
Can anyone explain what the #6 refers to in the extra large points made by USAT and Aristo-Craft? The smaller point are given a circle diameter but these are just called #6 and looking at them they don't seem to be a true curve but a curves and straight combined so I assume that they are not intended to have the curved section as part of a circle of track.
 
SevenOfDiamonds

SevenOfDiamonds

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#2
Can anyone explain what the #6 refers to in the extra large points made by USAT and Aristo-Craft? The smaller point are given a circle diameter but these are just called #6 and looking at them they don't seem to be a true curve but a curves and straight combined so I assume that they are not intended to have the curved section as part of a circle of track.
just lifted straight from a website (Understanding Model Railroad Switches) . . .

"Railroads use a numbering system to classify the frog of the switch. The larger the number, the longer the frog. Modelers commonly use that same number to apply to the entire switch.

The number of a switch, or frog, is determined by the units of run required to create a divide of 1 unit. In model terms, these units are usually inches. So, if it takes six inches of length for the center lines of the two tracks to get one inch apart, you have a Number 6 switch. This does not mean a Number 6 switch is six inches long. That dimension refers to the track centerlines. Most Number 6 switches are about twice that length from end to end.

One common misconception about model switches is that a certain number corresponds to a particular radius of the track. Switch geometry doesn't work this way, and switches aren't a constant curve radius."

So it looks like these are designed for crossovers, rather than being included in a curve.

Best wishes

David
 
SevenOfDiamonds

SevenOfDiamonds

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#3
,. . . though the #6 numbering seems to make more sense in this configuration . . .

111685_76e793ce46fa6a00d8c8014d60f92169.png


. . . than in this . . .

111687_50e620a9c67b619ebea9db113a653f0f.png


Best Wishes

David
 
Zerogee

Zerogee

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#4
By the look of the sleeper (tie) pattern in the USAT diagram, there is a short straight inserted between the two points (switches), which would account for the greater track spacing..... agreed, the first diagram shows the principle more intuitively.
Thanks for the info, I thought it was something to do with that but had never got round to searching for the actual definition!

Jon.
 
Gizzy

Gizzy

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#5
Basically, it's the angle of the frog....
 
funandtrains

funandtrains

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#6
David, thank's for the detailed explanation, I think I will get my head around it after reading a couple of times.
 
funandtrains

funandtrains

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#7
You have found some interesting diagrams.
 
Rhinochugger

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#8
My mind is wandering into some back lanes of past info here, but I believe that US turnouts in 1:1 land do not have any curvature on the frog - that section is always straight.

Hence, as is better explained earlier, the reference to turnout / frog by no. (or # as US short form for number).
 
David1226

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#9
I'm still having trouble with frogs on points as well

111699_2754091a54749c5129612c42ea4f8052.jpg



David
 
Zerogee

Zerogee

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#10
They look like they are metal, David - so if they short out on the points, does that make them electro-frogs.....? :rofl:

Jon.
 
David1226

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#11
They look like they are metal, David - so if they short out on the points, does that make them electro-frogs.....? :rofl:

Jon.
They look like they are metal, David - so if they short out on the points, does that make them electro-frogs.....? :rofl:

Jon.
Jon

Yes, but they are held together by spot welds, not rivet... rivet...

David
 
PhilP

PhilP

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5 Jun 2013
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#12
If they hold 'hands'.................


Do they complete the track-circuit?
:eek::giggle::giggle:
 
Greg Elmassian

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#13
I need to point out a statement that is not true:
"One common misconception about model switches is that a certain number corresponds to a particular radius of the track. Switch geometry doesn't work this way, and switches aren't a constant curve radius." "

prototype switches are RARELY designed so the diverging route is a constant curve radius (but look at city trolley lines)

unfortunately many model switches are OFTEN designed so that the diverging route is a constant curve!


Certainly in the case of LGB sectional track they are "curved".... making the diverging route exactly match the curvature of sectional track makes track planning easy.

"larger" switches are usually like the prototype.... especially when the frog number is given, and #6 and "up" is usually the dividing line between a diverging route that exactly matches a piece of curved sectional track, as opposed to a curve from the points to the frog, and then a constant, straight set of diverging rails.

So, all LGB are "curved", the Aristo wide radius and smaller, the USA trains switches "smaller" than the #6.... the "larger" Piko switches approach prototypes, as well as the Train Line ones.

You cannot make a generalization in this case of which brand is what, except LGB...

In terms of operation, there should be no difference, the "angle" of the switch's diverging route is a big factor, but so are many other factors in a switch, gauge, flange widths, frog geometry, wing rail flange widths, etc.

A fascinating subject, but somewhat tricky to understand as there is a lot of interaction between the switch geometry and the wheelset dimensions.

Greg
 
Fred2179G

Fred2179G

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#14
Can anyone explain what the #6 refers to in the extra large points made by USAT and Aristo-Craft? The smaller point are given a circle diameter but these are just called #6 and looking at them they don't seem to be a true curve but a curves and straight combined so I assume that they are not intended to have the curved section as part of a circle of track.
As they said, the #6 refers to the angle of the frog - it's a "1 in 6" angle, which you will be familiar with if you ever drove on a hilly road.

What has been implied but not stated explicitly is that the prototype track switch/point is straight through the frog. This is clearly seen in these images:
proxy.php?image=http%3A%2F%2Fwww.rail-fastener.com%2Fuploads%2Fallimg%2Fcombined-railroad-frog.jpg&hash=3e5611f0df97a7dc29680704ec36f002



And while that straight bit precludes you from having a perfect circle that matches the radius of the diverging track, you can assume the equivalent radius curve to be about 9 1/2 feet.

There's an easy to read clinic here:
https://www.google.com/url?sa=t&rct...-handout.pdf&usg=AOvVaw1lv5cdyc9o0lmSZ4xiFX2O