Does anyone else make a switch the size of the Aristo Craft #6. I have 8 on my layout, that's never had a car over them. I'm redoing my layout and I need a swich that a train can shove the switch open.
Tom
The head is gray, hands don't work , back is weak, legs give out, eyes are gone, money go's and my wife still love's Me.
Aye, Capt'n Bob, a Number 6 switch definitely can't directly replace a piece of sectional track, but if you want to complete a 90 degree curve with sectional track, it is quite useful to know how much to cut off a section so that things come out right. Now if the sectional track being used was the type where 20 made a circle, each section would be 18 degrees long and a half section would 'stretch out' the Number 6 to make 18 degrees. And if the sections were 15 degrees long, then a third of a section would work nicely. Of course straight sections or whatever would have to be added to make a loop but that's a nit in the great outside
E.R., thanks for the update. I figured it was a cut and dry mathematical exercise. Using 45mm for the gauge and 622.5mm for the outside radius, I come up with the same figure.
But empirical data is useful; I did make a mistake in using 45mm for the gauge, though; my mike shows the switch I measured to have a gauge of 45.2mm. That makes the outside radius 622.6mm, mathematically yielding an angle of 21.97 degrees with the frog to be located at 233mm from the start of the switch. Since the measured distance was greater, 239mm, the angle also has to be greater. I thought I was giving LGB the benefit of the doubt because of the points being placed behind the start of the switch but I doubt that that would affect things very much.
I had a math instructor once that insisted the number of significant digits in an answer could be no greater than the smallest number of significant digits in any factor involved in the final answer. So, I'll happily settle for an R1 switch having a frog angle of 22 degrees.
Art
All of which brings us back to my original caution. The LGB switches are made to replace a section of curve in a circle; the Aristo are divergent, thus cannot be used as a direct replacement for curved track!
With that caveat in mind, go for that which floats your boat!
kstrong wrote: Stickler for Detail wrote:To be precise the frog angle at point of intersect is 21.919º for the R1 (600mm) 11.231º for the R3 (1175mm) 11.206º for the R5 (2320mm) ER You sure about that frog angle for the wide radius (R5) switch? There's no way it can be more than twice the radius, but still have the same frog angle as the R3 switch.Later,K
Stickler for Detail wrote:To be precise the frog angle at point of intersect is 21.919º for the R1 (600mm) 11.231º for the R3 (1175mm) 11.206º for the R5 (2320mm) ER
21.919º for the R1 (600mm)
11.231º for the R3 (1175mm)
11.206º for the R5 (2320mm)
ER
K
Our techie goofed on the subtractions :
R1 = 21.919º
R3 = 15.757º
R5 = 11.249º
He really should have caught that!
artschlosser wrote:E.R.. don't wish to nit-pick but when I measured the distance from frog to points, I effectively was measuring back from the end of the curve which is not easy to do accurately. But since the points start a bit away from the end of the switch, I would expect the precise angle to be greater than what I calculated from the distance I measured; i.e., how far along the curve did the frog lie.Are the figures you posted from calculations from physical measurements or from LGB data? Art
E.R.. don't wish to nit-pick but when I measured the distance from frog to points, I effectively was measuring back from the end of the curve which is not easy to do accurately. But since the points start a bit away from the end of the switch, I would expect the precise angle to be greater than what I calculated from the distance I measured; i.e., how far along the curve did the frog lie.
Are the figures you posted from calculations from physical measurements or from LGB data?
Art,
Our techie says:
The posted results are the theoretical ones generated in a CAD program using the known values of the respective dimensions i.e. duplicate/offset the centerline of both the rad and the straight by 22.500mm; extend a tangent from the intersect point of the offset lineof the rad. That line corresponds to the frog angle.
Cheers
artschlosser wrote: .................................And the frog of an R1 LGB switch? The entire switch is 300 mm long and curves 30 degrees. The distance from the points to the frog is about 239 mm, and using the diameter of the outer rail for computation yields an answer of 22.58 degrees. Mighty sharp. Art
.................................
And the frog of an R1 LGB switch? The entire switch is 300 mm long and curves 30 degrees. The distance from the points to the frog is about 239 mm, and using the diameter of the outer rail for computation yields an answer of 22.58 degrees. Mighty sharp.
To be precise the frog angle at point of intersect is
15.757º for the R3 (1175mm)
11.249º for the R5 (2320mm)
WoW! I never knew that much about the geometry of switch points! This will come in handy figuring out difficult areas on the layout I'm designing.
underworld
To get this thread back on topic, the angle that a Number 6 switch makes is germane.
A Number 6 switch is defined as a spread of 1 unit in 6 units of length. Thus to construct such a switch, measure six units from the frog point along one rail, measure 6 units along the other rail, and spread them apart one unit. This measurement should include the width of both rails.
In geometry, what we have here is an isosceles triangle, a base of 1 and two equal sides of 6. Trigonometry is used to figure angles from linear measurements of right triangles. Cutting an isosceles triangle down the middle creates two right triangles. Dividing ½ by 6 yields 0.8333; this is the sine of a 4.78 degree angle. Multiply by 2 to get the full angle of 9.56 degrees.
Now in real life, if the distance from the points to the frog was 100 feet, this switch would be a 9.56 degree curvature in railroad lingo. In 22.5 scale, 100 feet scales down to 53 and a 1/3 inches. The length of an Aristocraft Nbr. 6 switch is a figure I don't have.
The angles for other commonly used switches.
Nbr 4: 14.36 degrees
Nbr 8: 7.17 degrees
GROANNNNN. But I really, really DO like puns!!!
Thanks for all this guys, I take it the switches work ok then, strikes the right chord so to speak!!
Cheers,
Kim
What's really neat about the 'chord' system is that easements are so easy to create. For the first 100 feet, use the offset for a 1 degree curve, the next 100 feet - use the 2 degree offset, getting progressively tighter until the limit is reached as specified by the surveyor; of course coming out of the curve the procedure would be reversed.
Naturally, one could start the easement with something wider than a 1 degree of curvature, 1/2 or 1/4 no doubt, being used on high speed lines.
If the tables provide offsets for 1/4 and 1/2 chords, the narrow gauge lines could have just employed a 50 foot chord, using the 1/2 chord offset.
Same dictionary up here, that "h" makes all the difference.
Could have been too much wood on someone's mind.
ER, it's not surprising that degrees of curvature are not mentioned in an European book as it's strictly American, based on that 100 foot chord. Doesn't translate well into metric.
Don't know about Canada, but a cord in my dictionary is something flexible like a cable or a heavy string, and a chord is a straight line between points on a circle or three or more musical tones, triads, dominant sevenths. etc.
Your drawing of degree of curvature was neat! Wish I could master posting pictures, etc.
artschlosser wrote:Railroads cannot use a trammel and circle center to lay out an arc or a curved section of track. Rivers, mountains, hills prevent this. But a table can be prepared to use a simple method of using a straight line and measuring offsets from this straight line. The table has offsets for the various curvatures that are required.Some 60 years ago while in high school, I came across a book that described this method. 1. At the start of the curve, Point A, extend a line 100 feet to Point B.2. Consult the table for the offset needed for the desired curvature; at Point B, measure the offset at right angles from the line and establish Point C.3. Sight a straight line from Point A to Point C and extend the line 100 feet to Point D.4. At Point D, using the same offset from step 2, establish Point E.5. As in step 3, sight a straight line from Point C to Point E and extend the line another 100 feet to establish another point.This process is continued until the straight line is headed in the proper direction (called a tangent) that can be extended to the start of the next curve. Flags are positioned at points, A, C, E, etc., and the track crew grades the right-of-way accordingly.The table that I found had offsets specified for the mid points of the extended lines but I doubt that they were really necessary although they would define the curve more accurately. Art
Railroads cannot use a trammel and circle center to lay out an arc or a curved section of track. Rivers, mountains, hills prevent this. But a table can be prepared to use a simple method of using a straight line and measuring offsets from this straight line. The table has offsets for the various curvatures that are required.
Some 60 years ago while in high school, I came across a book that described this method.
1. At the start of the curve, Point A, extend a line 100 feet to Point B.
2. Consult the table for the offset needed for the desired curvature; at Point B, measure the offset at right angles from the line and establish Point C.
3. Sight a straight line from Point A to Point C and extend the line 100 feet to Point D.
4. At Point D, using the same offset from step 2, establish Point E.
5. As in step 3, sight a straight line from Point C to Point E and extend the line another 100 feet to establish another point.
This process is continued until the straight line is headed in the proper direction (called a tangent) that can be extended to the start of the next curve.
Flags are positioned at points, A, C, E, etc., and the track crew grades the right-of-way accordingly.
The table that I found had offsets specified for the mid points of the extended lines but I doubt that they were really necessary although they would define the curve more accurately.
Hello Art,
That is interesting.
Interesting enough for our techie to check how other railways do it.
We have a book from the RhB (Rhaetian Railways) which is strictly technical info on aspects of track geometry, various tables and formula.
The RhB uses 3 different "Cords" (10m; 15m; 20m), in addition to the main offset (1/2 "Cord") they also state the offset at 1/4 "Cord". Interestingly no mention is made of curvature expressed in degrees. OTOH 100ft converts to 30.48m, which poses the question: was a smaller "Cord" used for designing and laying out NG railways with tighter curves?
Interesting!
PS RhB uses the 1:x for turnout angles.
Follow up:
Even easier is a drawing
Looking at the drawing data it would appear that using a 100ft Cord and the resulting calculated angle is somewhat more complicated than stating the radius - be it in Imperial or Metric measures.
What is the origin of the method??
Another way of looking at the railroad's 'degree of curvature' and how it's defined.
In Geometry, a chord is a straight line connecting two points on a circle. A chord that passes through the center of a circle is the diameter.
The degree of curvature on the railroad is the answer to the question. ‘How many degrees does a 100 foot chord subtend?'. In layman's talk, if you extend lines from the ends of the chord to the center of the circle, what is the angle between the two lines. (In geometry talk, these extended lines are perpendicular to lines of tangency to the arc at the ends of the chord.)
Example 1: the degree of curvature is 1 degree. The track therefore curved but one degree during the approximately 100 foot length of track. It would take 360 sections of track, then, to complete a circle because there are 360 degrees in a circle. The length of track for that circle would be 360 times 100 feet or 36,000 feet. Dividing 36,000 feet by pi (3.14159) gives the diameter or 11,443 feet. Half the diameter is the radius: 5,722 feet(all numbers rounded to the nearest foot).
Example 2: the degree of curvature is 3 degrees. The track has curved 3 degrees during the approximately 100 foot length of track. Again, it would take 120 sections of track to complete a circle as 360 degrees divided by 3 equals 120. A circle with a circumference of 12,000 feet has a diameter of 3,814 feet and a radius of 1,907 feet.
Note that these calculations are approximations as a chord is always slightly shorter than the arc it subtends. But for angles less than 5 degrees, the two lengths are equal for all practical purposes. As an example of how great the difference can get, a 60 degree curve would have a radius of 100 feet but the circumference of that circle iwould be 629 feet, the chord is still 100 feet, but the arc it subtends is 629 feet divided by 6 or 105 feet rounded to the nearest foot
Marty Cozad wrote:I run 332 rail because its cheaper and I don't run little girly engines. heheheheheheh
You got that right. That is why I run with Code 332 rail.
Lionel collector, stuck in an N scaler's modelling space.
spikejones52002 wrote:Thank You Elisabeth Reymond.You are the first person to give me anything close to an intelligent explanation for a turnout number.Everyone else I questioned, would look at me like I should know exactly what is Small, Medium, and Large.Next I need to find out now they measure a curve by degree.
Thank You Elisabeth Reymond.
You are the first person to give me anything close to an intelligent explanation for a turnout number.
Everyone else I questioned, would look at me like I should know exactly what is Small, Medium, and Large.
Next I need to find out now they measure a curve by degree.
Hello again,
Here's what our techie has in his library:
Refers to curvature degrees used by the railroads
They use a 100ft "cord" as the standard, lay that cord inside the radius of a curve. Run two tangents from where the end points of the cord are on the radius to the center point of the radius. The included angle between the tangents is the degree of curvature for that radius.
Hope that helps
Eric Cooper wrote:Not to hijack Kim's thread, but what's the difference between Aristo's #6 Turnout and the Wide Radius Turnout? The catalog doesn't show the wide one.
Eric,
The wide radius turnout will fit into a 5ft radius circle i.e. the diverging route is a segment of a circle.
The #6 turnout follows proper conventions that the railroads use i.e. it diverges 1 unit side ways per 6 units in length.
Projecting the frog intersection of the wide turnout results in approx. a #4 turnout.
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