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Discussion Starter #1
What do the code numbers often quoted on switches mean? I bought some USA Trains #6 switches and then bought some #8 switches from switchcrarfters in oregon assuming they would have a wider radius. Comparing the two - they look identical. So what do the numbers mean (or what are they mean't to mean......)
 

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The number on switches refer to the degree the switched route diverges away from the main route. In other words a #4 switch means for every 4 units (feet, inches, yads, meters) down the main direction the diverging route moves out 1 unit. A #4 switch is quite sharp. A #8 switch means the diverging route moves out 1 unit for every 8 units down the main. Therefore the #8 switch is less sharp when compared to a #4. A #12 is even less sharp and so on.

Most switches on 1:1 railroads, especially mainlines may be #20 or higher, especially for hgh speed lines.
 

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Discussion Starter #3
Thanks - my brain is stuggling to do the maths here - how does this translate into radius?
 

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They really do not translate directly into radius. Some of the smaller switches are indeed curved to match existing radii, but usually at #6 and above they are patterned after the normal type of switch. You can look up the diverging angle and then calculate the length of the switch and how much it diverged and then calculate the equivalent curved piece of track.

Note well: the "number" of a switch is related to the frog angle, just as Pete explained it. The LENGTH of the switch can vary, so there is no magic formula to have the equivalent curved track.

I will tell you that a #6 is broader than 10' diameter though, just as a rough gauge.

Regards, Greg
 

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Just a side note not all switches on 1 to 1 are no 20 even in high speed territories unless they are used for diverging routes only and then they could be no 15 also. No 10s are use for most tracks that lead off to an industry from any main be it high speed or low. Also yhey had another option of an equal lateral turnout that was good for 50 mph no matter which way was traversed through the turnout. Later RJD
 

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It must be recognized that the "Numbered" switches represent two straight tracks at angles from a single point... NOT a curved track emanating from a straight track. The Number represents a length for a distance of divergence and that only holds true for straight lines.

The Number does not change for any particular measuring system or unit of distance... inches, feet, meters, millimeters, etc., even furlongs! A Number 10 switch is 10 inches long for 1 inch of divergence and 10 millimeters long for 1 millimeter of divergence and 2200 yards long for 220 yards of divergence (220 Yards = 1 furlong).

If it were "Curved" then at 10 centimeters it might be 1 centimeter of divergence but 10 inches it would have much more than 1 inch of divergence (maybe infinity!) because a curve is not linear (and at 10 inches it might have already curved to be perpendicular to the tangent track it emanates from).

Unfortunately, most folk perceive the switch to have a curvature and want to know what that curvature is so it can be mated to curved track or what part of a circle of curved track the switch takes the place of.

Also, some switches actually have a curved divergence and as such you have to know what unit of measurement to use to determine what the equivalent Number of the switch is.
 

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Semper,
Good post. I wanted to say something like that too. With our large scale switches we are talking two kinds of animals. The more toylike curved turnouts that are made to match the curves on sectional track and the more prototype numbered turnouts. It seems now that most of the new product falls into the more prototype numbered turnouts, which I think is a good thing for the hobby.
 

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Discussion Starter #8
Useful discussion and I'm learning from it. I guess the question is better posed the other way around - if you have a track with a minimum radius of 10 ft, what number switch is recommended?
 

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For 10 foot radius 20 foot diameter, the only switches I know about are the Aristo and USA 3 foot long units.

The LGB R5 if you can find it is about 12 foot diameter.

PS, the USA is exactly 36 inches long on the straight portion, it is not a metric length.
 

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A number 6 turnout would be the equivalent of about a 9.5' radius. I mostly use number 6's for yards and sidings amd number 8's for all passing sidings and crossovers. If you are planning on running modern equipment use the largest turnouts and radius that you can design into your layout,you won't be sorry.
 

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Llagas Creek has wide radius switches

http://www.cocry.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=LCRY

They list several different radius switches with the following recommendations:

#3 3-ft Radius
#4 4-ft Radius
#5 6-ft Radius
#6 9.75-ft Radius
#8 15.5-ft Radius
#10 26-ft Radius

BUT, every manufacturer of rail/track has different rail styles/profiles and if you mix brands/styles you might have some difficulty mating the track and switch. So I would recommend sticking with the same manufacturer if you can.

You should pick the next larger radius switch for your track curve so the switch eases into the curve.
 
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