building curved handlaid turnouts - help/advice needed before i start

[DeadheadGreg]

Hey guys.  I've got all of the turnouts needed for Phase I of my layout built except one:  a curved turnout.  I have all the parts needed (Details West frog, rail, CV tie-strip, Ultimate Throwbars), but I need to know if theres anything special I should take into consideration that wouldn't normally apply to a regular straight turnout?

Andy has a bunch of new stuff on building turnotus on his site, but nothing really talks about making a curved one. 

So, yeah.  Who here has built a curved turnout?  It will be a #7 with an outside radius of 22".  I'm not sure yet if i'll be going with hinged points or continuous point/closure rails.  Everything I've done so far is continuous point/closure rails, so thats probably where I'll end up. 

I just need to know if theres anything in particular i need to worry about as opposed to making a regular turnout.

Thanks guys!

[dehusman]

Never used any of those products to handlay.  Somehow I would think that a #7 frog would put a very long flat spot in the curve.  If the outside radius is 22" then the inside is probably something on the order of 19-20" radius.  I would think a #5 would be better, but then on curved switches I generally don't bother with figuring a frog number.

[tomikawaTT]

In building a curved turnout, you forget the frog number and go with the radii.  The frog will end up shaping itself - and will probably come out to something wierd like a #6.73 or #8.9 (both taken up, straightened and measured when former layouts were dismantled.)

My method of building curved turnouts calls for starting with the inner radius, then superimposing the outer radius on it.  It's important to avoid bends and bobbles in both, but the inner radius is more critical.

A quick and easy way to see how things are going to fit is to take a flat working surface (sheet of cardstock or paper, on a foam base) and draw out your radii, then bend a piece of flex track to each and see how they overlap.  I mark out the tie lines, cut the card stock to those lines and then use it as a template.  Where the cardstock is 44.5MM wide is the location of your frog point (16.5mm gauge plus 28mm for an 8-foot Atlas flex track tie.)  I use wood ties, an NMRA gauge and two three-point gauges, and do my rail shaping with a BIG flat file.

Just to show that I'm not simply blowing smoke, I have a yard throat with two three-way switches that curve to the left (all legs) and a mainline turnout on a superelevated curve that's physically right next to them and schematically almost a kilometer away as the ED16 (JNR catenary motor) flies.

Chuck (modeling Central Japan in September, 1964 - on flex with hand-laid specialwork)

[Loco]

 Don't forget to post some pics!

[wedudler]

 It's not hard to solder your own turnout. Here's my HowTo.

And this is one example.

 

Wolfgang

[Texas Zepher]

DeadheadGreg

I've got all of the turnouts needed for Phase I of my layout built except one:  a curved turnout.  I have all the parts needed (Details West frog,  ,  , Ultimate Throwbars), but I need to know if theres anything special I should take into consideration that wouldn't normally apply to a regular straight turnout?

I don't see any curved frogs in the Details West catalog.  Unless I missed something, if you use one of their stock units it will not really be a curved turnout.

Who here has built a curved turnout?

I've probably built more curved than I have straight.

It will be a #7 with an outside radius of 22".

A numbered frog on a curved turnout is irrelevant and meaningless. As the prior posters have noted, the frog of a curved turnout is dictated by the two radii of the tracks.  The frog should be curved along with the rest of the turnout (including the point rails).  As such there is no angle of departure from the straight track to measure a number from.  The greater the difference in the two radius the "sharper" the frog will need to be.