Minimum radius in n-scale?

What is the smallest radius I can get away with in n-scale for a 180 degree turn on an off-stage track (no one sees it, so it doesn't matter how it
looks), relatively short trains (20 car max), relatively short rolling stock (50' or less) and slow speeds (10mph)?
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How big are your lokies? That is the biggest factor.

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Switchers, e.g. SW1500. [I'm just starting. At this moment; all I've got is three freight cars and 20" of track.]

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Allan Abrahamse wrote:

The minimum sectional track radius is 9-3/4" for most brands. I'd stick with that.
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What if later he gets bigger power? Why limit things so much? When I was in N-scale, I noticed that things like steamers and large diesels did not like those tight radius curves. My minumum's were about 12 in as I recall and my main line minimum was 19 in. Everything was happy on the 19.
John

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John Franklin wrote:

OP said he was using short w/b diesel switchers and up to 50ft cars. Didn't say anything about bigger power in future. Me, I prefer the largest radius curve that will fit, just like you. But we aren't OP, are we? :-)
Have fun!
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As others have pointed out, 9-3/4" seems to be the smallest available in most makers' sectional track, although Kato now offers 8-5/8" (216 mm). To determine what looks and runs OK with your equipment, why not just get a couple of sections of flex track and try different radii? -- Bill McC.
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AllanAbrahamse wrote: What is the smallest radius I can get away with in n-scale for a 180 degree turn on an off-stage track (no one sees it, so it doesn't matter how it looks), relatively short trains (20 car max), relatively short rolling stock (50' or less) and slow speeds (10mph)? ----------------------------------------------------- I made an oval with flex track to test my equipment. It's 8" radius. Most of the locomotives and cars run ok on it. Of course, 80'-85' passenger cars won't and some larger locomotives don't do well. My GP18s and F7s do fine as do freight cars 50' and under. I'd say that if you have to use a tight radius like that, you could. Probably 8-1/2" or 9" would be better. Or as others mentioned, 9-3/4" would be a good choice if you have space for it. With 11", you can run almost anything.
Bill Bill's Railroad Empire N Scale Model Railroad: http://www.billsrailroad.net Brief History of N Scale: http://www.billsrailroad.net/history/n-scale Model Railroad Bookstore: http://www.billsrailroad.net/bookstore Resources--Links to 1,000 sites: http://www.billsrailroad.net/bills-favorite-links
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On Sun, 20 Feb 2005 00:36:27 +0000, Allan Abrahamse wrote:

It boils down to the engine & cars you use. Fleischmann guarantees that all of their engines & cars work on their 7+" radius turns. Realism might not be there with cars hanging over the side of the curves, but operationally they work just fine.
For a realistic appearance, 24" radius looks good.
Carolyn
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I would like to thank those who responded to this question. Your answers were very helpful. I believe I can accommodate 11-inch curves, and it appears I will see few problems. These tracks will be out-of-sight, so how it looks won't matter.

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degree
stock
I had an 11" radius return loop at one end of my previous layout set in the 50s, and I was able to run pretty much "everything" around it without much trouble. The notable exception was that I often had problems when I ran back to back PAs with body mounted couplers in their nose. The loco would uncouple from the leading car because of the overhang. Shorter locos with less overhang (such as F7s and GP7s) didn't give me any grief.
Regards, Ron
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I've been down this road, and it's painful, let me tell ya. 9-3/4" is the smallest commonly-available commercial sectional curve. And your small switchers and 50' cars will negotiate that.
BUT... don't do it. My first N layout had 12" minimum radius curves. Everything I owned would run on them, including medium-sized 4-8-4 steam locomotives. OR SO I THOUGHT.
The truth is, "run on" is a vague term. All my engines and cars could make it around those turns. But 20 car trains over 12 inch radius curves really start to push things, even if they are all nice Microtrains cars. Backing through curves like this is even worse.
So, on the new layout I vowed that 18" would be the MINIMUM. And most of my curves are more like 22". I reworked and reworked my plan until I could really stick to this.
I'm telling you that you'll be amazed at how much better everything runs, and how much more trouble-free it is, if you can get that radius broader.
If you were running 6-car trains with small switching locos, I'd say "go for it" and use 12" curves. But since you are talking 20-car trains, try for at least 14" if you can. The widest turns on my old layout were 14", and they worked pretty reliably, even with passenger cars and steam locos. But you'll still have woes trying to back a 20-car train through a curve like that.
At 18", the whole world gets better. I am amazed that I can back a 6-car string of Con-Cor passenger cars, headed by a steam loco, around thes curves with narry a hiccup.
So... 14" minimum, but if you can scrape up the room for 18", do it. You won't be sorry.
--- Max
Allan Abrahamse wrote:

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Snip

You've made a good point, Max but IMHO you just needed to work on your track laying skills a bit. My last layout had 11" curves and I could run 50 cars back and forth without much trouble. The track was Atlas code 55 and the cars were Atlas with LP flanges. All the rail joints were soldered and filed smooth.
I *did* need to be real carefull laying track (no nails - use glue) and after tracklaying, about 10 minutes of labor per joint was needed until things were reliable.
-- 73's es gd dx de Ken KGWX Grid EM17ip, Flying Pigs #1055, List Owner, Yahoo! E-groups: VX-2R & FT-857
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I have a Kato Unitrack layout that includes two 8 5/8 inch radius 180 degree loops on the ends. In addition, the loops are on a 2-3 percent grade.
I run 3 Atlas Dash 8-40BWs pulling 29 cars with no problems. I know I could run more, but my loopbacks limit the length of the consist. The only modification I made was to install a medium length coupler on the first car, since the Dash 8s use body mounted couplers.
I also run a Kato 11 car California Zephyr set pulled by a Kato F3 A-B-A consist. The passenger cars are 85 ft Budds. The set ran flawlessly the very first time. :-) It doesn't look particularly prototypical on the curves, but it did run.
Before buying the Kato CZ, I tried a set of Con-Cor passenger cars, but they would not remain coupled.
As several people mentioned, the tight curves do limit the type of loco you can run. I haven't tried to run a 3-axle locomotive, e.g. EMD E8/E9, SDs, Dash 9-CWs, as it would probably have a problem with the curves. Steam engines are more or less out of the question.
Mark
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