# HO Track Radius Curve Size for Attractive Layout



## jimben (Jun 27, 2018)

When planning my 4 x 8 foot layout I investigated 22" vs 18" radius curves at each end of track. I believe 22" radius makes an approximate 44" curve and 18" radius makes an approximate 36" curve. The 22" radius did not fill the corners of 4 x 8 board well and the 18" radius simply was not wide enough.

I added a 6" straight section of track in the center of the 18" radius and ended up with 46" width. It filled the corners of layout better and looks great.

I also have a 15" radius inner track with the 6" track in center. I use a trolley car on the inside track.


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## MichaelE (Mar 7, 2018)

I initially drew up my layout with 22" radius curves. After more investigation and a few changes to the layout tables and a re-draw of the curves i settled on a 24" radius for the outside curves and 22" for the inside curves. 303mm passenger cars will run on an 18" radius curve but they don't look good at all.

24" is barely acceptable, but with the table as high as it is and the track levels even higher in most places, the overhang is not as noticeable as it would be if you were looking over and down at the layout instead of at just below eye level. 

Viewing angles can overcome some compression short comings of building a railroad in limited spaces. Furthermore, a wider radius was not possible without sacrificing a curve radius in another place on the layout in the same amount of space due to the geometry changing with the radius getting wider.

The branch line in the mountainous area that ÖBB operates on is a 20" radius on the curves, but the equipment is shorter that is used on this line so the radius looks the same on the 20" as it does on the 22" and 24" radii with longer equipment. In addition, the mountain line branch is at eye level and is the highest on the layout. You can't see down on top of this line without a stepladder unless you're seven feet tall.


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## Andreash (Dec 30, 2018)

I use 26”..... I didn’t want any restrictions, and occasionally run 80 foot boxcars....no problems


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## mesenteria (Oct 29, 2015)

jimben said:


> When planning my 4 x 8 foot layout I investigated 22" vs 18" radius curves at each end of track. I believe 22" radius makes an approximate 44" curve and 18" radius makes an approximate 36" curve. The 22" radius did not fill the corners of 4 x 8 board well and the 18" radius simply was not wide enough.
> 
> I added a 6" straight section of track in the center of the 18" radius and ended up with 46" width. It filled the corners of layout better and looks great.
> 
> I also have a 15" radius inner track with the 6" track in center. I use a trolley car on the inside track.


Trackage that parallels the edges of the bench is staid, if standard. This is my opinion, of course, but when one has space, crafting the widest possible curves while staying away from ovals with straight sides is going to be more appealing. It may not be obvious just yet, but the image below demonstrates my meaning;










At right, the twinned mains parallel the far wall and backdrop, but they are several feet away and I can't really object to what they do way over 'there'. At left, though, much closer to where I am likely to be observing, the serpentine nature of the mains is much more aesthetically pleasing. Or, at least it's more 'interesting' than if it merely ran parallel. The bridge's angle is part of the desired effect.

You are slowly acquiring the ability to add elements that add interest or more visual appeal, and that's both natural, expected, and laudatory. Keep 'reaching'. When you next get to doodling and designing a future layout, try to make as little truly tangent track as possible, especially when you might be observing it from oblique angles near the edge of the benchwork.


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## wvgca (Jan 21, 2013)

mine is in the 1890's, so it's pretty narrow ... about twenty inch radius in HO .. mostly mining / logging in the far north ..
lots of elevation changes, just like the real ones


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## J.Albert1949 (Feb 3, 2018)

On30 limits what you can do on a 4x8 tabletop.

What "fits" is... what you have to use.


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## jimben (Jun 27, 2018)

J.Albert1949 said:


> On30 limits what you can do on a 4x8 tabletop.
> 
> What "fits" is... what you have to use.


I can always expand it to 8 x 16 or even larger


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## CTValleyRR (Jul 26, 2014)

"Attractive" is subjective. For you, an oval which tucks into the corners of a 4x8 sheet of plywood "just so" may be exactly what you want.

I'm more of in mesenteria's camp: I prefer broad, flowing curves with little tangent track that winds through the "countryside". 22" is my compromise between space requirements and realism.

To each his own.


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