Just when I thought I had it all figured out, Bob Brown, editor of the Gazette comes out with this New Products article that states F scale is actually 1:15, which is what ya get when you divide three feet into 45 mm, the width of our shared track. I’m confused. If 1:15 is what narrow gauge on 45 mm track works out to, where’d we ever get 1:20.3?
Perhaps MM
Hmm, yeah Rick, that may be it. So lemme get this straight. It’s 1:15 mm or 1:20.3 inches, right? If that’s so, doesn’t that muck up the whole labeling process? I mean, we name our scales, 1:20.3, 1:22.5, 1:24, etc. Now all of a sudden, we’re calling F scale, 1:15 instead of 1:15? For why?
our (in)famous 45 mm give us:
at 1:32 the european standard spoor of 4’ 9.6" (named gauge I)
at 1:22.5 the german “meter"spoor. -> 3’ 4” gauge (named gauge IIm)
at 1:20.3 a narrow gauge of -> 3’ 9.7"
Edit: 2’ 9.7" i made a mistake.
at 1:15 another narrow gauge of -> 2’ 3"
as far as that it’s easy and logic. take four and a half centimeters(4.5) multiply it by the scale, divide by 2.5 to get the 1:1 gauge result in inches.
standard gauge is:
in 1:32 - 45mm
in 1:22.5 - 64mm
in 1:20.3 - 71mm
in 1:15 - 96mm
as to the question, why your northamerican modellers associations could or would not follow the well established european denominations and had to introduce denominations like F(…k) “scale” will give us a nice theme to get cross about, for as long, as the hobby will exist…
oh, i forgot 1:24…
“cape gauge” it is called, if i’m not misstaken.
in that the 45mm give us a gauge of 3’ 7" with a standardgauge of 60mm.
My head hurts…
Not 1:15, but 15mm to the foot, and still 1:20.3
Actually F scale is more accurately expressed as 1:20.32
This will make a noticeable difference with longer measurements like the length of a car.
I’ve used 15mm to the Foot as an easy way to use a standard ruler to build in 1.20.3 (Sorry Geoff, my models aren’t accurate to two decimal places :] ) I have to thank Kevin Strong for promoting this idea years ago.
I do agree that expressing 1:20.3 (in inches) is the only proper way. The 1:15 fraction is flawed; it has feet on one side (the 1) and Millimeters on the other (the 15).
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Yes, 15mm to the foot is dead on accurate for F scale. I often use it or 1.25mm to the inch which is exact.
20.32 is still rounded off.
Bob Brown screwed up by trying to divide apples into oranges. Happens all the time. 
Korm Kormsen said:
our (in)famous 45 mm give us:
at 1:32 the european standard spoor of 4’ 9.6" (named gauge I)
at 1:22.5 the german “meter"spoor. -> 3’ 4” gauge (named gauge IIm)
at 1:20.3 a narrow gauge of -> 3’ 9.7"
at 1:15 another narrow gauge of -> 2’ 3"
as far as that it’s easy and logic. take four and a half centimeters(4.5) multiply it by the scale, divide by 2.5 to get the 1:1 gauge result in inches.
standard gauge is:
in 1:32 - 45mm
in 1:22.5 - 64mm
in 1:20.3 - 71mm
in 1:15 - 96mmas to the question, why your northamerican modellers associations could or would not follow the well established european denominations and had to introduce denominations like F(…k) “scale” will give us a nice theme to get cross about, for as long, as the hobby will exist…
Actually, not quite right. 
45 mm is 1.771654" We’ll assign G=1.771654
So, 45 mm gauge gives us
- 1:32 G*32=56.692928. Or 4’ 8.7" (A bit more than 4’ 8.5", but very close)
- 1:22.5 G*22.5=39.862215 (3’4", as you said) A meter is 39.37008"
- 1:20.32 G*20.32= 36.0000093 (VERY close to 3’)
- 1:15 G*15=26.574 (2’ 2.574") Though the 2 foot modelers typically use 1:13.7, which gets you much closer to 2’.
I’m not sure what you’re doing with
as far as that it’s easy and logic. take four and a half centimeters(4.5) multiply it by the scale, divide by 2.5 to get the 1:1 gauge result in inches.
But, why not just multiply by 1.8? (4.5/2.5) = 1.8. Besides, if I do this with 20.32, I get 36.576.
Here’s how I get the full size gauge in inches:
I multiply the scale times the gauge.
So, for 20.32, I multiply 20.32 * 1.771654" = 36"
Or, to find the exact scale (something that Geoff would use ), you take the full size gauge and divide by the scale gauge. So, for 3’ narrow gauge, 36" / 1.771654 = 20.3199948.
It’s just that very few of us want to say we model 1:20.3199948
Bruce Chandler said:
(SNIP!)Here’s how I get the full size gauge in inches:
I multiply the scale times the gauge.
So, for 20.32, I multiply 20.32 * 1.771654" = 36"
Or, to find the exact scale (something that Geoff would use
Whew. I thought after all of that I’d been doing it wrong all this time. (or, possibly that railroad tracks were actually further apart than I’d remembered…)
Matthew (OV)
Here in UK railroad modellers have ALWAYS lived with a mix of metric and imperial dimensions.
British n scale = 1/160th scale, or 2mm to the foot - runs on 9mm track
British TT scale - 1/120th scale, or 3mm to the foot - runs on 12mm track
00 scale = 1/76th scale, or 4mm - runs on 16.5mm track
British 0 scale = 1/43rd scale, or 7mm to the foot - runs on 32mm track
British Gauge 1 = either 1/32nd scale, or 10mm to the foot scale, but both run on 45mm track.
As for the little narrow gauge stuff, I’m not going there…but 00n9 - 4mm to the foot running on 9mm track - gives you a taster.
tac
Ottawa Valley GRS
**Bruce Chandler said:**So, for 3’ narrow gauge, 36" / 1.771654 = 20.3199948.
It’s just that very few of us want to say we model 1:20.3199948
I dunno; maybe you’ve just discovered a new name for the narrow gauge rivet counter: A Three One Niner Niner!
So much for editorial proof reading in the Gazette. At least one of us here had the correct interpretation of the flawed print.
As for the EXACT scale, how fine do we want to split the gnat’s eyelash? Come on fellas, how many of us can even accurately measure .0001". Generically when talking about 3" narrow gauge running on 45mm track I refer to it as 1:20. Does the rest really matter? Unless of course you are building to compete in a competition put on by that standards group (don’t want to start a flame war).
And if you really want to pick nits, 2’ narrow gauge on 45mm track would be 24 / 1.771654 = 1:13.54666317, not 1:13.7.
Bob C.
Now we seem to have sorted out the widths between rails how about the rail height? Reference to the 1:1 railroads will show that there are many rail weights and heights.
I am content with code 332 as my short line carries a lot of coal freight as I guess the MOW chief has decided on a heavy rail - no rock and roll railway here, lol
Bob Cope said:
And if you really want to pick nits, 2’ narrow gauge on 45mm track would be 24 / 1.771654 = 1:13.54666317, not 1:13.7.
Bob C.
Ah, but most 2’ gauge RR are actually 60cm, or 1’ 11.5". How does that work out?
I’m just glad I model 1:29th, so I’m never cornfused…
Well I’m always confused… But that doesn’t even have anything to do with gage/scale, it starts wham the alarm clock goes off at Oh-Dark-Thirty everyday.