# N-Scale design parameters



## /6 matt (Jul 7, 2015)

I'm planning an n-scale layout built off of a hollow core door for the distant future, It will most likely be up against a wall for space reasons so I will most likely going with a 30" door, possibly a 32" so I can sneak wider curves. My main question is I'm having a hard time finding standards for design. I'm planning on modeling the transition era. Would 15" radius curves be suitable to reliable run up to a 4-8-4 steamer? What about 14"? What should I spacing should I use between parralell mainline tracks? Also what should my overhead clearance be for any crossovers?


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## DonR (Oct 18, 2012)

Here is the NMRA standards for track work. You should be able to
find what you are looking for. 

http://www.nmra.org/index-nmra-standards-and-recommended-practices

Don


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## Brakeman Jake (Mar 8, 2009)

I am actually building my layout that I've been planning for a few years so far and,though a little larger(120 in.X 80 in. L-shaped),it will have a lot in common with your projected layout.

At first,I desired three mainlines with one over/under setup somewhere,plus a yard,a substantial cattle raising facility,a town and a few industries...was I ever in for a surprise!!!I had to compromise way beyond what I expected.

The first place I couldn't compromise is overall size.I've used all the space the room allowed.Then came the second parameter I couldn't cheat on...curve radiuses.My roster (mostly articulateds) commands large curves.

Though Athearn say their articulateds can handle tight curves (11 in. for Challenger,12 in. for Big Boy),they do but look silly doing it.Then Intermountain recommends 15+ in. curves for their Cabforwards.I think a 4-8-4 will be happier with such curves too,a 2-10-2 may require even larger curves.

So,after drawing,erasing,re-drawing multiple times,here are a few of the compromises I've come up with:
-One double track mainline (or two mains) with minimum 16 in. curve radius.To achieve this,I went for a 40 in. deep benchwork.It won't be too comfortable to work on at times but had not much choice.
-I dropped the over-under idea.A steam era loco (and cars) will need a 1 5/8 clearance from railhead (modern double-stacks more like 1 7/8) wich meant about 2 in, climb depending on bridge thickness.Just to stay within a 2% incline would have needed 100 inches of ramp tracks both sides,a lot of landscape for a small layout.


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## /6 matt (Jul 7, 2015)

So here is a design concept I came up with, minimum overhead clearance is 2.1" and max grade is 2.1%. Minimum mainline radius is 14" and minimum radius on spurs is 13" The design uses a 32"x80" hollow core door and two 35" x 25" shelves from wayfare.

Let me know what y'all think.


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## jargonlet (Dec 21, 2011)

I'm not too sure about the radii that the steamers need but I like your design. I like that you are using a passing siding. Something I far too few of on single track layouts. You may want to check spookshow to see what your steamers can handle.


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## DonR (Oct 18, 2012)

Very nice continuous running layout with some potential for
switching.

First, you have a reverse loop situation where the teal track crosses
from lower left to upper right. That is good if you are going to use
DCC. There is a DCC automatic reverse loop controller that eliminates
the need for complex wiring and switches.

I also would make a yard as part of the maroon tracks inside the
right loop.

Don


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## /6 matt (Jul 7, 2015)

DonR said:


> Very nice continuous running layout with some potential for
> switching.
> 
> First, you have a reverse loop situation where the teal track crosses
> ...


That's what I was aiming for :smilie_daumenpos: Do you think I have left enough room for scenery? It's hard for me to gauge being as my brain is wired to think in HO. 

I'm aware of the reverse loop and I am planning on going with an NCE power cab for control. Any recommendations on cheap auto-reversers? I see name brand (NCE, Digitrax etc) run around $50 and that seems like a lot of money for piece of equipment that will power one ~30" piece of track.

I took your advice and placed a yard in where that one industrial siding was on the right side. The two top tracks are for engine servicing and the bottom track is the switcher home/caboose track. I can't help but feel like it looks a little awkward in the middle of that loop. Anybody have any thoughts? Also I redid the top-left tracks to make it a little more expansion friendly.


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## Brakeman Jake (Mar 8, 2009)

I like the basic design too.However,I'm worried that 13-14 in. radiuses may be too tight for the larger 4-8-4's as they usually require 15+ in. rad.Having larger wheels (most times) thus having longer rigid frame driving trucks,they are more critical of radiuses than let's say an articulated Challenger.

My suggestion is that you build a simple test loop with these radiuses and test your projected locomotives.It would be a shame to realize,after all the work,that the layout doesn't fulfill what it was built for in the first place.

Even if they don't derail,locomotives running on very tight radiuses get their pulling power severely impaired because their wheels tend to run jacked up against their flanges thus not having a good contact with the rail surface.Result is poor traction and prematured wear due to frequent spinning.

It's frustrating to find out that a high price loco can hardly pull only two or three cars up a curve.I'd make sure all the wheels fully seat on the track with these curves before I'd build.


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## DonR (Oct 18, 2012)

The Digitrax AR1 is a very good reverse loop controller and
it is less costly.

http://www.amazon.com/s/?ie=UTF8&ke...qmt=e&hvbmt=be&hvdev=c&ref=pd_sl_60wx661zbt_e

You might shop around for an even lower price.

The way some of us get more industries and other buildings on
a crowded layout is to cut the depth of the building...It may be
an N Scale 100 feet wide, but only 25 feet front to back.

I see a lot of green in your layout images where you can put hills, tunnels and
buildings. Nothing wrong with crowding things together...that's the way it
is sometimes in the real world around railroads.


Don


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