Approximate Radii Of Atlas 2-Rail #5 & #7.5 Turnouts ?

Tom Tee posted:

A numbered turnout is the ratio of the  degrees of frog angle.  A radius is a constant arc of curvature.. 

Oil and Water.

Well, yes, but I think a little emulsification is in order.

The Curved Closure Rail has a radius between its two tangent portions;  this radius will generally vary slightly depending on how long the tangent sections at frog and swing ends are, but generalizations can be made.   The data sheet in an Old Pullman catalogue shows their #5 0 scale turnout having a nominal 52 inch radius;  an Atlas #5 might vary a bit from that.

The Standard Drawing for a UP #7 [ as low as they go ] turnout shows a [ c/l ] radius of 353' 10 13/16".

If a locomotive, especially lwb steam, has an advertised minimum radius of n, one would not purchase a turnout with an effective radius less than n, and [ Opinion ] it would be good practice, space permitting, to go at least one number higher than the minimum where possible.

With best regards,

SZ

Edited to add:   I used lwb as an abbreviation for long wheelbase, but from memory wasn't LMB Models the tradename for the 0 scale of Leonard Blum of Blum's Hobby House ?  He had some Really Nice Stuff in his personal collection.......

#5 and/or 7.5's will be perfect for any of the 3rd Rail engines. Obviously bigger is better but #5 will work while #7's eat up space quickly

Matt01,

Not basic information - you can fit whatever radius you need and create a compound curve for the divergence.

The Atlas #5 is 11.25° of the arc and the Atlas #7 is 7.5° of the arc.

Atlas #7 - Knowing that the curve from the straight mainline starts at the frog, scaling down railway engineering works. Leaving out the background, each 1° of center angle equals a radius 5730 feet. Dividing that by 7.5 (degrees) equals a radius 764 feet. Scaling that down to 1:48 (764 x .20833) = a radius of 159.164 feet. Sheesh, a 318 foot circle - will that fit on my 4' x 8'?

I then made sections of flex track in SCARM of a radius of 159.164 feet and arc of 7.5 degrees to make a piece of sectional out of a piece of Atlas 2-rail flex. Looping them all the way around comes back to the frog, where the divergence begins. Not exact, but really close and proves that Atlas uses scaled down railway engineering standards.

The #5 would be 5730/11.25=509.33 x .20833= 106.109 radius

see attached

Thanks for the info, everyone. Helpful and interesting.

Atlas is the only source for "ready-to-run" 2-rail turnouts? If I wanted a turnout other than a #5 or #7.5 .... I would have to use one of the semi-assembled turnouts from BK INDUSTRIES? Or, build them myself? 

Matt

I would suggest, as mentioned above, Signature Switch:

http://signatureswitchco.com/number_turnouts.html

These are beautifully made and Brad made some code 125 #5s for me for switching. I think they are much superior to Atlas for a comparable price.

Brad Strong of Signature Switch Co is making fantastic turnouts of standard and custom configurations.

www.signatureswitchco.com  or 801 884 6354.  Some samples of his work:

We needed to have 4 tracks within 83 degrees so Brad made this 72" radius  ladder with the points backed all the way up to the frog.  He made the component breaks in the middle of the turnout.

To save hook up time he optionally will provide feed drops the color of your choice.

This #8 double crossover is one of the most silent pieces of track work I have ever installed.  You can see the train cross it but you do not hear it.

I have gotten dozens of his turnouts with great satisfaction.

If you look close above in my earlier interchange post you will see four of his custom switches.

I also recommend the Signature Switch turnouts.  They are more durable and way smoother than Atlas.  They may be cheaper too.  Brad did have a backlog last time I ordered (maybe a year ago?) but they were worth the wait.  You also get more of a choice especially if you include the ability to order custom turnouts (I have several custom curved turnouts).

I consider them ready to run.  They do need to be painted and a hole drilled for whatever turnout control you use.  

My mistake. Tom ... when you mentioned Brad Strong and Signature Switch in your first post, I assumed it was a very expensive custom builder. I did not further check him out. Thanks .... Tom, Bill, and John .... for guiding me to Signature Switch.

I'm now just about sure that I'm making the change from 3-rail to 2-rail.

Matt

I had a simple 8’ long 2-rail diorama for many years that had a pair of Atlas-O #5 turnouts. I am building my first 2-rail layout & after reading older articles on the 2-rail forum, I decided to go with O-Scale Turnouts. I picked up my first turnout, a #8 at this year’s Chicago O-Scale meet from Bill & it looks much better than my Atlas turnouts. After I complete my benchwork, I plan to order more turnouts from them.

I might have seen another turnout maker at one of the more recent Chicago meets, but O-Scale Turnouts just seemed more realistic to me at that time.

Bill is very accessible & had even e-mailed me the CAD files of his turnouts to help me with my layout planning. Here is a link to his website.

O-Scale Turnouts catalog & price list

These are just my opinion,

Thanks,

Naveen Rajan

naveenrajan posted:

I had a simple 8’ long 2-rail diorama for many years that had a pair of Atlas-O #5 turnouts. I am building my first 2-rail layout & after reading older articles on the 2-rail forum, I decided to go with O-Scale Turnouts. I picked up my first turnout, a #8 at this year’s Chicago O-Scale meet from Bill & it looks much better than my Atlas turnouts. After I complete my benchwork, I plan to order more turnouts from them.

I might have seen another turnout maker at one of the more recent Chicago meets, but O-Scale Turnouts just seemed more realistic to me at that time.

Bill is very accessible & had even e-mailed me the CAD files of his turnouts to help me with my layout planning. Here is a link to his website.

O-Scale Turnouts catalog & price list

These are just my opinion,

Thanks,

Naveen Rajan

Do you have any photos of that Diorama? I have an 8-foot space I was thinking of putting a display in (2-rail) and am always looking for ideas.

I just installed a couple of #8 switches from Signature Switch, and they are excellent products!

Just to be clear about switches: the Number of a switch, which is the number of the frog, (No. 8, No. 10, etc.) does not state "the ratio of the degrees of frog angle."

The number designation of the switch (or frog) states the rate of divergence of the two tracks. In a No. 8 switch, the rails diverge at a rate of 1 in 8 when measured from the "theoretical" point, as described below in the following quotation from "Railway Track and Structures Cyclopedia (Simmons-Boardman 1955, p. 378). 

"The number of a frog is one-half the co-tangent of one-half the frog angle, or the ratio of the spread at any point to the length of a bisecting line between that point and the theoretical point of a frog."  The theoretical point of a frog is defined as follows: "The theoretical point of a frog is the intersection of the gage lines of the frog." The "actual" rather than "theoretical" point of the frog is the point where the spread between the two gage lines is 1/2 inch.

And of course each frog number ( 6, 8, 12, 20) is directly related to a specific frog angle. In practice, frogs are made in a limited number of standard numbers, although a frog could be custom made to a different number for a special application (a No. 8.36, for example). 

Well, I'm not sure I'd say the switches are particularly well detailed. Certainly not when compared with a switch built from Right o' Way parts, which include rail braces, built-up or cast frogs with nut/bolt detail, tie plates, cast switch rails with nut/bolt detail and reinforcing plates, cast guard rails with nut/bolt detail, switch point tie-bars, gauge plates, and so on. But The Signature Switch products are indeed very well made, are perfectly in gauge, operate flawlessly and, best of all, come ready to install.

O-Scale Turnouts uses Right-of-Way castings & offer turnouts with all the extra details in both O-Scale & in Proto-48. They offer all their turnouts in 2 configurations. The first Base version is just the turnout, without most of the ties with special tie-looking pieces soldered to the underside to maintain the gauge. The next Ready to Lay version is comparable to a ready-to-install turnouts with all the ties. To the extent I still remember my discussion with Bill at this year’s Chicago O-Scale meet, you could enhance the looks of the Ready to Lay or Base version with tie-plates & rail joiners shipped loose in a Detail Kit.

These are just my opinion,

Thanks,

Naveen Rajan

You're right -- I guess I confused the two companies (O Scale Turnouts vs. Signature). The website for O Scale Turnouts lists switches that are available with different levels of detail. 

AGHRMatt posted:

naveenrajan posted:

I had a simple 8’ long 2-rail diorama for many years that had a pair of Atlas-O #5 turnouts. I am building my first 2-rail layout & after reading older articles on the 2-rail forum, I decided to go with O-Scale Turnouts. I picked up my first turnout, a #8 at this year’s Chicago O-Scale meet from Bill & it looks much better than my Atlas turnouts. After I complete my benchwork, I plan to order more turnouts from them.

I might have seen another turnout maker at one of the more recent Chicago meets, but O-Scale Turnouts just seemed more realistic to me at that time.

Bill is very accessible & had even e-mailed me the CAD files of his turnouts to help me with my layout planning. Here is a link to his website.

O-Scale Turnouts catalog & price list

These are just my opinion,

Thanks,

Naveen Rajan

Do you have any photos of that Diorama? I have an 8-foot space I was thinking of putting a display in (2-rail) and am always looking for ideas.

Here is link to a Flickr album with photos of my diorama over the last 4 ½ years.

https://www.flickr.com/gp/102964084@N05/GqS36H

Thanks,

Naveen Rajan