Making Crossovers with Curved Turnouts

[peahrens]

I've got a layout plan roughed out (using XTrackCAD) that seems best if the two crossovers I want functionally are incorporated into a dual track curved section. 

With straight track crossovers, I'd simply pair #6 or #8 turnouts, no problem.  Since the curved turnouts have dual radii, do you have any advice on how to choose which ones to pair or what to avoid.  As an example, pairing two #7.5 Walthers Shinohara code 83 (nominal 32/28 radii) would mean an outer curve of nominal 32", a crossover consisting of a 28/32 connection, and an inner curve of nominal 28.  

In the example, the nominal outer and inner curves are more different in radius than I want the connected "parallel" curves. Plus, visually it looks like the crossove end points may not curve together very symetrically (i.e., go off at weird angles relative to each other.  Attached transitions can adjust for thios but I wonder what tends to work best. 

Some questions:

a) is it often better to combine different # turnouts in a curved crossover?. For example, a #7.5 with a #7 or #8?  This seems to worsen the issue of excessive outer and inner curve radii difference so I'd guess the answer is it's usually best to combine the same # turnouts.

b) does it help to add a transition piece between the connection to get the curves better aligned in a smooth way?  This would tend to spread the track spacing (perhaps too much) so perhaps alternatively would it help to trim one or both diverging tracks to change the exit angles to "match" better ?

I realize there may not be a right answer to this as it depends on the connected curves, etc, but any experience here would be appreciated.  And I know from another post that someone commented that the inner radius is often 2' or so less than the nominal radius. 

c) Is there a way I can get full size photocopies of the turnouts? Can Walthers provide them? The catalog diagrams are too tiny (even if enlarged) for me to trust. Or, are the XTrackCAD geometries accurate enough to trust, for selecting turnouts? The expensive way would be to buy one of each, but then I may end up with some $50 turnouts I'll never use.

Thanks for your advice.   

[cv_acr]

I'm not sure this helps you, but the crossover under the locomotive in this photo from my club layout is built on a curves. The switches are handlaid, not store-bought.

http://www.wrmrc.ca/layout31.html

[selector]

First, do not trust the stated radii of the Walthers/Shinohara curved turnouts.  If anything, they are less, each route radius, but near 3".  You will probably want a W/S curved #8 if you can get one.

Secondly, it really is quite a bit better to hand lay such appliances.  All you need is the rail stock, a cutter, soldering stuff, a decent mill file, and some ties, including a least four or fived PCB copper-coated ties to ensure proper connectivity for each turnout.  Or, draw it out carefully in scale, and send the diagramme to someone who makes such things for sale.  It will cost you about $40 handlaid by someone else, give or take a few bucks, but it will fit in there perfectly, and run better.

Crandell

[cuyama]

I've had good luck laying out curved crossovers in HO with PECO's #7 curved turnouts. Walthers work fine too, but they are so long that it can create complications.

 

To create a crossover using curved turnouts, I find it works well to curve the crossover track between the turnouts. That extra curved track between the turnouts helps provide the track-to-track spacing throughout.

I use the desired track-to-track spacing as a guide to be sure that the tracks don't come too close to one another. In this example, curves are in red, straight tracks and the turnouts themselves are in black.

It just takes some fiddling to make it all work, in CAD or on the benchwork. I find that the radii I end up with are not intuitive at all, but the results work.

Although handlaid track is always an option, it's certainly not a requirement for curved crossovers.

Byron

[tomikawaTT]

cv_acr

I'm not sure this helps you, but the crossover under the locomotive in this photo from my club layout is built on a curves. The switches are handlaid, not store-bought.

http://www.wrmrc.ca/layout31.html

After looking over the available commercial products, I decided to go all hand-laid.  As a result, I have one yard throat with three-way switches where every route curves left, a bunch of curved and semi-curved switches built to radii that I (not the commercial maker) specified, and the peace of mind that comes from knowing that the gauge and curve radii were laid as designed and that there are no rail joints in awkward locations (like 25mm away from the sharp ends of the points.)

The fact that I saved enough to add a couple of locos to the roster doesn't hurt my heart, either.

Chuck (Modeling Central Japan in September, 1964)

[Renegade1c]

This particular curved crossover was because we added a staging yard under the mountain and needed a way for the double track main to be able to get in and out. This crossover was handlaid by yours truly. It consists basically of a #6 left-hand switch and a 60" radii curved turnout (this is rough estimate as it was actually custom built for this particular location). The curved turnout is on the outside track. The #6 turnout is on the inside. 

[dante]

I agree with Byron's comments and am doing the same with Walthers/Shinohara curved, in my case a #8 and a #7.5 with a short, curved spacer.  And I am the guy who has frequently noted the disparity between the W/S published radii and the actual:  the divergent, smaller radii are typically 2" less than advertised.

Dante

[Don Z]

I had the privilege of visiting Gil Freytag's layout a couple of years ago. This piece of beautifully hand-laid track work is on his layout. While taking the photo, Gil told me if I was to learn one thing from my visit, it would be to never put such an item on my layout. He told me it was the most cantankerous piece of track on his whole layout even though to me it appeared flawless. When an MMR speaks, this newbie listens.

Don Z. 

[Pennsy nut]

Thanks for that input Byron - the Peco turnouts are exactly what I was planning on using and my radius is pretty close to what you show, so I think they are going to work out for me...  thanks for the confirmation!