Atlas Code 55 Curved Turnout

[glakedylan]

FWIW:
Atlas code 55 curved turnout
outer radius will form a circle when connecting together. the circle is 21.25 in radius.
inner radius will also form a circle (with the need to add one piece of Radius 15, 16 degrees) that is 15" in radius

[ednadolski]

Makes sense, those match the radii of the Atlas C55 sectional track.

[signalmaintainer]

Most of my qualms with Atlas code 55 curved turnouts have been allayed -- once I pulled my head out of my a&$.

https://realisticmodelrailroading.net/forum/modeling/track/18361-what-i-learned-from-a-frog

[jeffstri]

I have 6 Altas curved turnouts, 4 on the main and 2 connected in series in a locomotive maintenance area. Other than one I damaged during installation (broke a point rail), problems with the curved turnouts have been similar to and no more frequent than with the other fifty #5, 7 and 10 turnouts I’ve installed. So far I have no reason to consider replacing any of them.

There seems to be a misunderstanding about the geometry of these turnouts. The curvature radii are not uniform but are 21.25” and 15” in the frog and closure rails, less curved in the point rails, and the approximately one inch stock rails ahead of the throw-bar and after the frog are straight.  So you can’t just cut out a section of a 21.25” or 15” curve and drop the turnout in.  You need short lengths of straight rail in the adjoining tracks, or you’ll end up with ugly transitions (no easement) or distort/damage the turnout.  Also, if you connect two curved turnouts in series, the resulting arc of the two has a flat 2” segment in the middle, and the radius of the overall arc will be about 2” more than the nominal 21.25” or 15” of the individual turnouts.

[spr1955]

I had one on my last layout with few problems, albeit that it was in an area that did not get a lot of traffic.  Now I do have one on the main that feeds an industrial siding/spot, so far just running traffic thru it and again only using it for that industrial job.  If it goes wonkers I will either fix,based on what the problem is or go with one handlaid and be done with it.

[wm3798]

I had two on my old layout that never gave me a stitch of trouble.  I still have one of them still mounted to the board that used to be Cumberland.  It's been in storage in the garage for almost 10 years.  It would be interesting to excavate it and see if it has suffered any ill effects.  It's embedded in ballast, and as far as I know, hasn't been subjected to anything other than hot/cold cycles. 
Hmm.  Could be worth a gander.
Lee