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One thing that has been puzzling me for a while, how do you work out what MM a layout is?

I understand;

2mm = N Gague
4mm = 00 Gague

How do you work it out, as at first I assumed it was track width.
It is not essential I know, but handy if ever I am about and they list things in MM.

Many thanks
 

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2mm / ft is N gauge, with the track width set at 9mm.

4mm / ft and track width of 16.5mm is OO gauge.

As standard gauge is 4ft 8 1/2", OO is a compromise designed originally to allow the more prototypically narrow British loading gauge locomotives to be modelled, but using the same track as HO gauge (Continental Europe, USA and Australia etc.).

Regards,

Dan
 

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N can come in a variety of flavours. There's 1/148, 1/150 and 1/160 at least. That's before we get to whether it's N Scale or N Gauge.
 

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The Scale of the model is the ratio between the size of the model and the size of the prototype. This can be expressed either as a ratio or as so many millimetres per foot. Some examples:

Standard Gauge

Scale Name

Ratio

mm/ft

gauge (mm)

O

1:43.5

7

32

OO

1:76.2

4

16.5

HO

1:87.1

3.5

16.5

N

1:160

1.9

9

Z

1:220

1.4

6

Narrow Gauge

Scale Name

Ratio

mm/ft

gauge (mm)

G

1:22

14

45

OO9

1:76.2

4

9

HOe

1:87.1

3.5

9

HOn2-1/2 or HO30

1:87.1

3.5

9
 

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Just out of interest, what scale are the Del Prado models, eg. Flying Scotsman, 1/160 or 1/148?
 

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2 mm/foot scale isn't N gauge....and doesn't 'use' 9 mm track gauge, as such......unless the builder really wants to.

but, then one gets into the 'finescale' end..for example...4 mm/foot scale..ie 1:76-as-near-as-dammit...called ''OO'' gauge when using a track gauge of 16.5mm......becomes ''EM'' when using a more closer-to-scale 18.2mm gauge of track....[it confused me, because when I started, EM gauge track was at 18mm.......someone sneaked behind my back and changed it]...then there's ''P4''..or even once, 'S4'..which uses the same scale, but a gauge of 18.83mm.

O gauge also has its problems...especially with the USA having a 'coarse' O scale....plus there is ''Scaleseven'....

Actually...track 'gauge' is really rather an irrelevance...if you see what I mean......

because, the actual 'gauge..whether prototype or model, is really only an approximation, since it will vary according to circumstances....[gauge widening on curves,for example?]

With 4mm, and other scales, teh 'finescale' bit really refers to...in PW terms, the tolerances regarding flangeways, checkrail gauge, and wheelsets.....especially wheel profiles.

also, it seems, 'finescale' now refers to 'fidelity to protoype'......regarding appearances,....

and operations.....including infrastructure.

I pity those modelling in N .

especially with the European propensity for changing the actual scale ratio to suit ???
 

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To add to the confusion I am interested in 7mm Narrow Gauge but that has 3 different scale/ratios

In UK 7mm/1ft 1:43.5 and so 2ft gauge line should be 14mm gauge - however most modellers use 16.5mm (same as standard OO/HO) and it is then known as O16.5

In USA their O scale is 1/4in/1ft which is 1:48 and using 16.5mm track is known as On30. They also use On2 to represent 2ft gauge using 1/2in gauge and On3 is 3ft using 3/4in gauge.

Continental O scale has a ratio of 1:45 and using 16.5mm track is known as Oe

Hope I got all that right


Mike
 
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