Railroad Forums 

  • Minimum turnout sizes and curve radii

  • Discussion related to everything about model railroading, from layout design and planning, to reviews of related model tools and equipment. Discussion includes O, S, HO, N and Z, as well as narrow gauge topics. Also includes discussion of traditional "toy train" and "collector" topics such as Lionel, American Flyer, Marx, and others. Also includes discussion of outdoor garden railways and live steamers.
Discussion related to everything about model railroading, from layout design and planning, to reviews of related model tools and equipment. Discussion includes O, S, HO, N and Z, as well as narrow gauge topics. Also includes discussion of traditional "toy train" and "collector" topics such as Lionel, American Flyer, Marx, and others. Also includes discussion of outdoor garden railways and live steamers.

Moderators: 3rdrail, stilson4283, Otto Vondrak

 #22398  by Engineer Spike
 
You see in MR that the owners of these large layouts say that they will not use a switch smaller than a #6 and that they have 1/2 mile minimum radius curves. I was wondering what you use? For a home layout, would #4 be relaible for use as yard ladder switches? I do plan to use a #6 or 8 for main line crossovers.
One last question is, is the Atlas "y" switch long enough to use on the main? If not, who makes a longer one? I nned these because the B&M uses equallateral switches at the end of double track locations, in places like Tyter (Athol) and Erving interlockings.

 #22593  by Throttle_JCKY
 
Personally, I don't use anything on the mainline itself smaller then a #6.
The smallest crossover I use in a control point is #8. All industrial leads off the main are #6. I have a couple #10's in CP's also.
The only locations on the layout I have anything smaller then a #6 are in the industrial tracks and leads. The yards is mainly #5 and #6. I use #4 turnouts are sparingly as possible.

From the times I have seen the Atlas wye switches on layouts, it appears to small. Now in an industry or yard, it would be ok.

I don't use Atlas turnouts, only Walthers -SHINO's code 83.

http://www.trainweb.org/cior

 #22755  by Otto Vondrak
 
Our club layout uses #6 on the main, and #5's in one yard... mostly #4 for sidings and industrial tracks. #5's are only available from Shinohara in Code 83... if you're building your first home layout, then #6 on the main, and #4 for the sidings and ladders would be a pretty safe bet.

If you have the room, larger radius turnouts are always better.

Our minium radius on the club layout is 26". Most home layouts have 30" minimums. It all depends on how large your layout is, what kind of equipment you will run and how much room you have. Long E-units and passenger cars? SD40-s and auto parts boxcars? You need larger radii. GP9's and 40-boxcars? You can get away with smaller radii.

-otto-

 #22994  by Chuck Walsh
 
Nothing less than 22" if you want to run the new/bigger stock and the Walthers Budd passenger cars require 24".

18" is perfect for two axle diesels and 40' cars.

 #23002  by Ken S.
 
Chuck Walsh wrote:Nothing less than 22" if you want to run the new/bigger stock and the Walthers Budd passenger cars require 24".
Not true, I run the Walthers cars with an 18".

 #23061  by Chuck Walsh
 
The 24" is the radius recommended by Walthers and I will not challenge
those guys.
 #23094  by march hare
 
Wow, how do you get Walther passenger cars to run on 18 inch radius track?

My home layout uses 32 inch minimum, but at Christmas time I set up an under the tree loop that uses 18 inch, with a section of 22 inch as a transition into each curve. Even with the transitions, I can't get Walthers cars around the curves. They derail every time.

Are you doing anything special to the cars?

 #23185  by CRail
 
I cant get the 85' budd cars to work on 22" radius, i highly doubt they will work(without being modified) on 18" turns

 #23267  by Chuck Walsh
 
These Walther Budd Cars have been out since the fall of 2001. I have
covered every budd post and they are still posting budd problems over on www.atlasrr.com as we speak.

I concur with March & CR.

Share your secret with Walthers and maybe they will change the specs
on the box/insts.

 #23315  by Otto Vondrak
 
You can run whatever you want on 18" radius... but it will look better and perform better if you use a wider radius. Just a simple fact.

-otto-

 #23365  by CRail
 
you cant run something around a turn if it wont run around the turn

 #23435  by jwb1323
 
The problems of running around sharp curves include whether the wheels will hit coupler boxes, underbody detail, skirts, steps, etc. I agree with those who say that 18 inch radius is best left to B-B diesels and 40 or at best 50 foot cars. I'm wondering if the poster who says he runs Walthers cars around 18 inch curves may be meaning the more recent short heavyweights.

Within limits -- some brass items, for instance -- most equipment will go around a 24 inch curve. I believe the actual radius of an Atlas #4 turnout is 24 inches or so, too. So once you get beyond the 24 inch hurdle, larger radii are mostly for visual effect. This does not mean you can run 4-12-2s on 24 inch, nor that large locos of any sort will look much good. I have some Overland diesels, PRR BP20s and CNJ double-enders that will not do 24 inch as well.

 #23533  by dti406
 
The reason the Atlas #4 is 24" radius is that it actually is a #4-1/2 Turnout. Ir you were to use another manufacturer's #4 turnout it would be somewhat less than 24" radius and therefore unusable in yards where 60' and 86' high cubes or 89' flats are used with their larger radius requirements.

Rick

 #25866  by Don Gibson
 
Ken S. wrote: I run the Walthers cars with an 18".
RUN ?

They dont couple or uncouple.
'Too tight' causes 'too many' derailments.
... AND they look so realistic!

My analogy might be 'trying to park a Cadillac in an outhouse.

 #25912  by atsfman
 
min. switch, #6
min. radius 32" most 36"

Bob