Can I go smaller than 18" radius for my N scale layout?

Shortliner13 Sep 9, 2017

  1. Shortliner13

    Shortliner13 New Member

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    So I'm building a N scale layout of a shortline that's in the Appalachia mountains. The longest piece of equipment I'll have on the route is the 4-6-0 steam locomotive and the Harriman Passenger cars. Both of which I measured out to be 5" long. Now originally I thought that the minimum radius I'd be able to run was 18". This is probably still true, but I'm also wondering if I could also go to a smaller radius.

    Any suggestions?
     
  2. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    You can probably go down to ~12" operationally without a problem -- possibly further. With your equipment, there won't even be much overhang.
     
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  3. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

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    The answer is yes. But I wonder why? Is it a space restriction? Or? The smaller you go, the more chance of potential problems.
     
  4. Shortliner13

    Shortliner13 New Member

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    Because I don't know how to make circular benchwork for the layout. I can do a simple 2x4 sectional, but anything beyond that.
     
  5. bremner

    bremner Staff Member

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    do you mean diameter? 18" diameter is a 9" radius, and there is no way for an 18" radius will fit on a 2x4
     
  6. Shortliner13

    Shortliner13 New Member

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    Okay I am confused, every article and website I've read been talking about minimum curves in terms of radius.
     
  7. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    What John is referring to is that a 2 foot by 4 foot section is 24" x 48". A perfect circle with 18" radius is 36" diameter, so won't fit on 2' x 4'. To fit that means dropping your radius to between 10" and 11"
     
  8. Shortliner13

    Shortliner13 New Member

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    I think John is right. I'm pretty sure I got radius and diameter mixed up.
     
  9. bremner

    bremner Staff Member

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    N Scale locos (for the most part) are designed to operate on a 9 3/4" radius, which will fit nicely on a 24"x48" layout. While it is possible to use a smaller radius, it is not recommended without testing it first.

    I, myself, am thinking about making a streetcar layout using a 6" radius curve.
     
  10. BarstowRick

    BarstowRick TrainBoard Supporter

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    Now that we have radius and diameter figured out. Allow me to share the following.
    I run a minimum of 18" radius on my mainline which handles just about anything you want to run. On some siding and yard tracks I go down to 15" radius and it handles most of my freight trains with those scale 89' autoracks hanging over. I have 3 24" radius curves and everything looks amazing as they run those curves.

    I've been known to say the widest curves are the best curves. You can choose for yourself what you think is best.

    Let's see it sounds like you are making a door layout with a 2X4' width which will limit you to 10" radius. Anymore and you'll be hugging the edges of your door or benchwork.

    Street cars! You got to love them. I have a trolley line with 7 3/4" radius curves. It isn't pretty but it is fun to watch my equipment crawl around it.

    My two cents.
     
  11. Doug Gosha

    Doug Gosha TrainBoard Member

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    I think John Armstrong said that the largest mainline radius curves you can get away with ARE the best.

    Doug
     
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  12. BarstowRick

    BarstowRick TrainBoard Supporter

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    Yes sir! I concur!
     
  13. Point353

    Point353 TrainBoard Member

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    Sure there is. You can probably fit up to about 22" radius.

    The OP said 2'x4' sections - think of two (or more) Ntrak modules set up back-to-back, with a pair of 2'x4' end units having 180° curves.
    In this case, given the 4" setback from the front edge, the end curves would be about 20", 18.5" and 17" radius - depending upon whether or not the skyboards are installed.
     
  14. acptulsa

    acptulsa TrainBoard Member

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    Recap, just to make sure you've got it:

    Your 2x4 modules can take a northbound train and turn it completely around and send it out southbound. If you use 9 3/4" radius track, you can run straight track down about 3/4 of the long side, turn the train within the width of the short side, and run more straight track down about 3/4 of the length of the other long side. There is a lot of N scale equipment out there that won't be happy on 9 3/4" radius curves, but you can loop back on a layout which only reaches two feet from the wall to the outside edge. In fact, you can put a whole oval-shaped loop on a 2x4' layout.

    If you use 22" radius track, a semicircle will pretty much take up a whole 2x4 module. One end of that curve will be a few inches from one corner, and the other end will be a few inches from the other corner down at the other end of the long 4' side. You won't have room on that same 2x4 module to run that main line down any straight track at all. 22" radius curves will make just about any N scale equipment under the sun happy as can be, but to loop back you have to have four feet of depth from the outside edge to the wall. You have to piece two 2x4' modules together (or build one 4x4' board) just to have one perfect circle of track. But you will have comfortable margins at the edges.

    Clear enough?
     
  15. jdetray

    jdetray TrainBoard Member

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    Sometimes a picture is worth a thousand words. Below is a 2x4 track plan showing an oval with 10-inch radius curves. The blue circle has a diameter = 20 inches. Radius is always half of the diameter; in this example, radius = 10 inches.

    - Jeff

    [​IMG]
     
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  16. Doug Gosha

    Doug Gosha TrainBoard Member

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    Thanks for the excellent illustration, Jeff.

    And I still love that B&M logo (what did we call it in the old days?).

    Doug
     
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  17. Metro Red Line

    Metro Red Line TrainBoard Member

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    As someone who left HO scale because of the radius issue, and refuses to go less than 18" radius in N scale, yes, you can, but for heaveN's sake, try not to go less than 15" if you want to enjoy this hobby.
     
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  18. jdetray

    jdetray TrainBoard Member

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    I respectfully disagree with such a blanket statement. You can very much enjoy this hobby in N-scale with curves of less than 15-inch radius. While I completely agree that big curves are wonderful and desirable, they aren't required for enjoyment.

    For example, I'm physically disabled, and building a large layout was problematical for me. On the theory that ANY layout is better than NO layout, I'm having great fun with my 32x48-inch N-scale layout. Curves are as small as 9.75 inches. I'm constrained to running 4-axle diesels and 40-foot rolling stock, but the layout runs well.

    I'd hate to see would-be model railroaders with physical challenges, lack of space, or small budgets give up on having a layout just because they can't have one with sweeping turns. There is a whole world of terrific small layouts out there. See Micro/Small layouts for model railroads for many fine examples.

    - Jeff
     
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  19. Nimo

    Nimo TrainBoard Member

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    As most replies already mentioned, the broader you can go, the better, but one of the main reasons why people chose to model in N scale is so that they can 'have' a layout in the first place without the additional burden of space. What radius is 'minimum' is a very subjective matter in model railroading and depends on 3 key factors:

    From practical standpoint:
    1. What space do you have
    2. What locomotive and rolling stock you wish to run
    From authenticity standpoint:
    1. How do you present your scene in relation to your locomotive and rolling stock - whether what you present is 'prototypical' or not
    As for equipment, ALL commercial N scale locomotive and rolling stock can manage a 12 inch radius without breaking a sweat unless specifically mentioned otherwise in the product description - that does not mean you will model a big-boy to run over a 12 inch radius curve unless that portion of the track is hidden.

    If you wish to run longer locomotives and passenger trains, but don't have enough space, hide your tight curves in well scenic tunnels on both sides - it's classic model railroading. If you don't wish to make tunnels but still have to use tight curves, make a layout that only uses small switchers and 40 ft box cars.

    If you're thinking there are no prototype that you can fit such small curves and in a 2X4 sheet of plywood, well, you're wrong again! plenty of urban and industrial railroads used curves where a 9 3/4" radius curve in N scale would be prototypically 'too broad' - the best examples are the famous transfer terminals in New York, like the Harlem Transfer: http://members.trainweb.com/bedt/indloco/ht.html

    Good luck, and don't be afraid of tight curves, as long as you know what you are doing! Space restrictions and mobility are the two things that I have been battling ever since I started with model railroading, and trust me when I tell you this, you can make 'fabulous' layouts in small spaces. I have some designs in my website that might be of help: http://www.trainsanddioramas.com/resources/model-railroad-plans/

    Kaustav

    P.S. If you use tight curves, ensure to use easement curves - most derailing issues on tight curves can be handled by simply placing easement curves to transition to straight portion of the track.
     
    Last edited: Sep 16, 2017 at 4:02 AM
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  20. Hardcoaler

    Hardcoaler TrainBoard Member

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    I think it depends on what kind of equipment is run and the quality of trackwork. I've had no problems whatsoever with 14", 12" and even 11" radius curves on my 30+ year old N Scale road.
     

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