EX-Track Switch Geometry

[rjarmuth]

Need to know the radius and length of a curved track to use with #5 and #6 so that I can run the "turned out" leg parallel to the main leg from which a train has exited.  Eg: do I use a 22" radius 9" long curve section to "bend" the track exiting from a main line with a #5 switch, back so it's parallel?

We know that a 9" long 18" radius track will bring a standard (unnumbered) switch turned leg parallel to the main line -- but how about for #5 and #6 switches?

[ABC]

Technically it can't be done unless you make custom sections of track by cutting to fit.

[OldTimer]

Use flex track.  Adjust the reverse curve on the siding so that when the two tracks end up being parallel, they are on about two inch centers.  Depending on the turnouts you are using, you may be able to trim the diverging route back a little which will let you use a more gentle curve while maintaining the 2" separation. 

If you feel like you have to use sectional track, here is an Atlas example.  For a #6 turnout, add a 4 1/4 inch fitter (made up of a 1 1/4" section and a 3" section) to the diverging route, then add a 1/3 18"R piece to turn the track back.  The resulting two legs will be 2" apart and close enough to parallel, and you don't have to cut anything.

Hope this helps.
OldTimer

[Joe Satnik]

Dear rjarmuth,

http://www.anyrail.com/index_en.html 

Free CAD download.  Play around with it. 

If you click on the divergent route end of a turnout, it will tell you the departure angle. 

Subtract the departure angle of the main route.  The result is the divergent angle. 

Match the divergent angle to the degrees of turn of your curve. 

360 / #of sections per circle = degrees of turn of your curve.

Hope this helps.

Sincerely,

Joe Satnik