# Switch Tracks in relation to curves



## John J (Dec 29, 2007)

Some where on MLS was posted a chart that showed the relationship of switch tracks to curves.

I down loaded it and not cant fine it in my documents file or on my HD.

Any one got a copy.

Yes I did a Google search.

JJ


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## Tom Parkins (Jan 2, 2008)

I found this chart on Greg's web site. Is this what you are looking for?

GB "R"
number
common LGB
track number
degrees
per section
switch
number
frog
number


true radius
MM
true diameter
MM
true diameter
inches
true radius
inches
* closest* foot
diameter
*closest *foot
radius 
R1 11000 30 12000 2 600 1200 
47.244 23.622 4' 2' R2 15000 30 none 
778 1556 61.26 30.63 5' 2-1/2' R3 16000 22.5 16000 3.5 1198 2396 94.33 47.16 8' 4' R4 see note
~3500
~11-1/2' R5 18000 15 18000 5 4640 182.68 91.34 15' 7-1/2' 

Greg, I hope this is okay?



Keep in mind that when you start using prototype switches you are really not talking about the radius of a curve. The switch (turnout) number is related to the angle of divergence. A piece of curve may be attached to the switch. A number 6 switch diverges 1 foot for every 6 feet of straight. #10 diverges 1 foot every 10 feet etc. 


Turnout Number Angle 
4 5.06” 

6 9° 32’ 

8 7° 09’ 

10 5° 43’ 



Modeler's make HUGE compromises on switches just as we do with our curves. While we think that a #6 switch looks amazing on our garden railroads, on the real thing a #6 would only be found in yards. Even #10 switches are only found on branches or sidings. Main line crossover switches are typical #15 - #20. 


Speed on turnouts (switches) is very roughly twice the turnout number. Typically a #10 is 15-20 mph. A #20 switch is 40 mph. I've had the pleasure of running 1:1 Mikados and Pacifics on the main line at 60+mph. Then you slow to diverge from #1 to #2 track. Believe me you can feel the side to side thrusting a whole lot more on a big engine than you do in the coach. Oh and don't let the track maintainers catch you spinning your drivers through the crossovers!


Tom


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## Greg Elmassian (Jan 3, 2008)

No problem Tom, the site is there to help the community! 

Greg


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## John J (Dec 29, 2007)

Thanks Tom Gave me some information that I needed. Well probably use R 4s and R5s. 

JJ 

PS I just realized that I posted this in the wrong forum.


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## Dwight Ennis (Jan 2, 2008)

PS I just realized that I posted this in the wrong forum.I moved it.


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