New Zealand Rail Models in 9mm Scale

(Scale ratio of 1:33.87)

G 4-6-2

Nelson Kennedy, Christchurch, NZ.

Take me straight to the models!

Why such an odd ball scale?

This scale has been chosen because it provides a correct scale to gauge relationship when standard 0 gauge track (32mm gauge) is used to represent the NZR prototype gauge of 3' 6".

Isn't it difficult to scale plans to this size?

Whilst it seems like an odd ball scale at first glance, in practice it is easy to use because most plans have been published in imperial measurements and it is an easy task to multiply the stated measurement, in feet, by 9 to derive the scale measurement. And in this age of clever photocopiers it is an easy matter to take a plan drawn to 1:64 (most have been published in that size) and set the copier to 189%!

Is there any support for this scale?

This scale is a minority one but its following is growing. Some cottage industry manufacturers have been encouraged to make some components available. This is a non commercial web page so it is not appropriate for me to mention suppliers by name, however I am willing to answer questions in email at

Nine Mill Scale track and wheel standards

The standards adopted by Nine Mill scale modellers in New Zealand and supported by the small band of manufacturers are very close to dead scale as is shown by the following table. The main compromise is in the area of track gauge where a 0.5mm overscale gauge has been accepted as the price of an easy to use scale ratio and an off the shelf track product (being standard 0 gauge track). That is a small compromise compared to the errors widely accepted in other parts of the hobby like British 00, US 0 scale and G scale. It can even be argued, maybe a little tenuously, that the 0.5 mm error is within the tolerances of prototype track widening on sharp curves in the steam era of long fixed wheelbases. Howzat?!

Nine Mill Scale Wheel Standards
Dead Scale
Nine Mill Standard
Track Gauge
42 inches
31.5 mm
32.0 mm
Back to back
29.0 mm
Loco tyre width including flange
5.625 inches
4.22 mm
4.25 mm
Wagon/car tyre width including flange
4.5 inches
3.375 mm
3.375 mm
Flange depth
1 inch
.75 mm
.75 mm
Flange width at root
1.06 inches
.795 mm
.8 mm

The Models

The following links will take you to pages for specific models, or classes of models which I have built unless otherwise stated.

D 2-4-0T  

'Scott D' class 2-4-0T of 1884

G 4-4-0ST  

'G' class 4-4-0ST of 1873

F 0-6-0ST  

'F' class 0-6-0ST of 1872

W 2-6-2T  

Addington 'W' class 2-6-2T of 1889

G 4-6-2  

Rebuilt 'G' class 4-6-2 of 1937

30' van  

Passenger rolling stock and guard's vans

M-1 wagon  

Goods rolling stock

Wd class loco

Other People's Models
Yours could be here - email me!

Drop me a line, - by email 

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Updated 19 September 1998