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Minimum Radius in N


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What is the minimum radius curve in N gauge?

Thinking of building a layout that is about 4ft long but possibly 2ft wide if I could get a curve round that size board, thinking of a fiddle yard at the back with a curve to the front.

Also has anyone the measurements for MK1 coaches and a largeish tender loco.

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Small locos (0-6-0's) will go round 9" radius curves without problem, as will 4 wheel wagons. If you can, aim for a minimum of 12" radius (3rd radius setrack) curves, as most models are much happier.

 

2nd radius setrack )will allow most things to go round, but the effect is hardly realistic. My test track consists of 2nd radius curves, and while I've yet to find a model which won't go round, my Dapol B17 does graunch a little!

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There is no definite minimum radius in N gauge (or probably in any scale/gauge). You can purchase set track at 9" radius and less, but these days the limitation is more likely to be the stock you chose to run rather than how tight you can bend the track. Therefore it's probably best to avoid any pre-concepts about 'minimum radius' and go for as large a radius as you can. There are a number of reasons for this;

 

1) To future proof your layout regarding new stock - as modern products are released and the fidelity of them increases there is a tendency for them to require larger (and increasingly so) curves to traverse and work well. Many already recommend a minimum radius for best operation that is greater than 9". Some even suggest 12â€.

 

2) The curved track will look and be more realistic with larger radii.

 

3) The trains will look better and more realistic on larger radius bends with less overhang.

 

4) It helps avoid buffer locking and running problems.

 

5) You'll be able to have closer (and therefore more realistic) coupling gaps.

 

6) It is always best to stay away from the design limits if you want the best results and least problems. You do not have to be an experienced modeller to appreciate that constraints exist and that approaching them means nearing the limits of efficient trouble-free operation and acceptable performance.

 

G.

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A 4ft x 2ft board, assuming you're doing an oval, doesn't leave a lot of space.

 

We've already ascertained the tightest recommended setrack curves are 9" - so that's 18" of circle. Three inches top and bottom space, and an inch space at the end of the board gives you 28 inches of 'straight track' in the middle for something like a station. If you want a point to run into some sidings, that's 3-4 inches you can cut off too at least. Double track? Even shorter.

 

I think it might help if you gave us some idea about what your plan is so we can comment on whether it'll fit, or any suggestions we might be able to make to assist you to maximise the space you have.

 

Is 4ft x 2ft the biggest space you can have? In N gauge, even another six inches can make quite a difference.

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  • 3 weeks later...

I've built several microlayouts with curves down below 7"

 

Generally the diesels are happy at 7", kettles less so, although most 0-6-0 stuff will do 7".

 

Union Mills 4-4-0's will do 5" as I discovered this Christmas ;)

 

Kato eurostar needs 216mm (smallest Kato curve) and will not do anything below that - its clearly engineered to just make 216 !

 

Below 7" it gets a bit touchy as the couplings begin to force stock off the track and the drive mechanisms on bogie diesels are really being pushed out of spec, but my mini BP&GV scene ran for a while with 5.5" curves, 03's (Farish 04 conversions) and Trix hoppers (Farish and Peco won't do 5.5 !), plus a railbus or two. It now has the (fortunately offscene) curves relaid using 7" because the new 08 (converted to an 08/9) won't do 5.5"

 

For sanity I would suggest the minimum you want is 9" for modern image, 10.5" for steam. The shift from 9 to 10.5" makes a big difference for close coupling so if you can get it up to 10.5 it's a big win. For a double track that may mean as the cromptonnut says the extra 6" makes a big difference - and I would say a worthwhile one.

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Union Mills 4-4-0's will do 5" as I discovered this Christmas ;)

 

Now that's an interesting thing to hear - I'm currently working on a microlayout for use at uni, and it has to fir on a 1' by 5'6" shelf, so I'm using Tomix 140mm (~5.5 inch) radius curves. I have two Farish 0-6-0 tanks, both of which have the flanges ground off the centre wheelsets (by hand, with a file. Took a long time!) and a Farish class 04, which just about grinds its way around the curves. Certainly the couplings on my Peco short-wheelbase wagons "work" on the curves, as in they'll hold a rake together about 95% of the time, but they certainly won't couple - they're simply at too large an angle to each other. I'm still looking into possible ways of curing this. I'd say stick with 9 inch curves as a minimum, then you can use the Peco Setrack system, which is much simpler. Oh, yes, and on Tomix 140mm radius curves, three mark one coaches take up 180 degrees of the curve, so look a wee bit silly!

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  • RMweb Gold

11" is the minimum radius on my layout; with the larger contemporary American diesels and long rolling stock items this is close to the practical minimum, I'd suggest. Obviously UK stock may accept tighter curves but it would always be best to future-proof yourself. Even those 11" curves (which are concealed) have needed quite a bit of fine-tuning to get reliable running.

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What is the minimum radius curve in N gauge?

Thinking of building a layout that is about 4ft long but possibly 2ft wide if I could get a curve round that size board, thinking of a fiddle yard at the back with a curve to the front.

Also has anyone the measurements for MK1 coaches and a largeish tender loco.

 

Hi there

My N gauge layout used to be 2 feet wide and the curves were a strain on anything bigger than a Castle, especially seeing the bufferbeam overhang; I purposely added another couple of inches width on the current one to incorporate Peco 3rd radius curves which are about 12" - things are much smoother now....

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