G Scale Model Train Forum banner
1 - 20 of 28 Posts

·
A Steamed Elder
Joined
·
3,857 Posts
On a visit to George's home last July, I saw this model. It is magnificent! This thing will be huge! He took my son and I on a little tour of his workshop. We knew we were in the domain of a true Master Modeler. We felt very privileged to be shown his work.
 

·
Registered
Joined
·
114 Posts
RE: F scale D&SL 2-6-6-0 #212

This thing is going to be awesome AND HUGE!!!! I do however have a question. This model is going to be F scale, standard guage, so would'nt that make it 1:20, not 1:20.3? I thought the 1:20.3 was for narrow guage. I know the lettering for narrow is technically Fn3 vs F for standard, but I was under the impression that the .3 was to specify running on 36" track.
This will be my early learning for the day

Thanks
 

·
Premium Member
Joined
·
584 Posts
RE: F scale D&SL 2-6-6-0 #212

The difference between scale (the size of the object compared to full size) and gauge (the distance between the rails) is often confusing.
In F "scale" the models are 1:20.3 the size of the real object whether they are narrow or standard gauge. This came about when the defacto standard 45mm track was used to represent 3 ft narrow gauge. The models were changed in size, the track remained the same. To further muddy the waters some modelers wanted to use 45mm track to represent 2 ft narrow gauge so increased the size of the models again to 1:13.7
Confused yet?
Then some folks decided it would be neat to show the contrast of standard gauge models to the smaller narrow gauge. The models are still built to 1:20.3 scale but the gauge of the track was increased to 70-some millimeters (I can't remember off the top of my head)
As for the F scale nomenclature as I understand it Fn3 means 1:20.3 scale models running on 45mm track. Fn2 would be 1:20.3 scale models running on 32mm track and F standard gauge 1:20.3 models on 70+mm track.
To further confuse things, if you want to model standard gauge on 45mm track the proper scale is 1:32 but for various reasons 1:29 has become the standard scale for that but I won't go there.
Hope this helps,
Tom
 

·
Premium Member
Joined
·
2,195 Posts
Paul,
For further clarification: The proper scale for 45mm track representing 36" gauge is actually 1:20.32! This, of course, is getting to be "rivet counter" ridiculous so we tend to round the number up. Some people go for 1:20 which is pretty darn accurate and most have gone one step futher and use 1:20.3 (go figure.) As you have eloquently pointed out, using only the 1:20.3 nomenclature doesn't distinguish between the various narrow gauges and standard gauge! This is the reason I prefer to use "Fn3" with (1:20.3) after to clarify. Hopefully, someday "F" Scale will come into the same recognition that "O" has (yeah, I know.....there will be a winter storm warning in hades when that happens...) Still, Fn3 is the only way to tell the scale and gauge! Now, as to every other scale running on 45mm track, well.....good luck and welcome to the "goofy gauge club!"


By the way, I believe that standard gauge in F Scale is 70.64mm.
 

·
Premium Member
Joined
·
4,393 Posts
The way that I have settled on, to keep things straight is;
[*] Decide what you want to keep constant.

[*] Model Track Gauge: In the case of Large Scale (G-Gauge, G-Scale, #1 Gauge) for what ever reason, the de facto decision was to keep the gauge of the model track at 45mm. To do this the 'scale' ratio of the model to the prototype has to change to keep things in proportion.
For example;

[*] 1:13.7 Scale = Represents 2-foot gauge prototype track, with 45mm gauge model track.
[*] 1:20.3 Scale = Represents 3-foot gauge prototype track, with 45mm gauge model track.
[*] 1:24.0 Scale = Represents 3'-6" gauge prototype track, with 45mm gauge model track
[*] 1:32.0 Scale = Represents 4'-8 1/2" gauge prototype track, with 45mm gauge model track.

Any models of the various prototype equipment need to match the appropriate scale ratio listed above to maintain the proper proportion.



[/list] [*] Model Scale Ratio: If it's decided that the scale ratio is to remain constant, then the model track gauge has to vary to keep things in proportion.
For example;
[*] 1:20.3 Scale = Represents 2-foot gauge prototype track, with 30mm gauge model track.
(Note, since there's no commercial model track of this gauge made, 32mm gauge track has been substituted, or you can hand lay your own.)
[*] 1:20.3 Scale = Represents 3-foot gauge prototype track, with 45mm gauge model track.
[*] 1:20.3 Scale = Represents 3'-6" gauge prototype track, with 52mm gauge model track.
(Note, since there's no commercial model track of this gauge available, then you're left with hand laying your own)
[*] 1:20.3 Scale = Represents 4'-8 1/2" gauge prototype track, with 70mm gauge model track.
(Note, since there's no commercial model track of this gauge available, then you're left with hand laying your own)
[/list] [/list] [/list]
 

·
Premium Member
Joined
·
436 Posts
Discussion Starter · #9 ·
Steve not to nit pick....Well I guess I am.....I'm sure you know difference, but for those than may not know...... :) :)

F is a scale which is a ratio 1:20.3 .....or 15mm = 1'-0" (about 9/16")

In all the other scales HO. S, O, even in N gauge the way to designate the gauge track that is other then the standard 4'-8 1/2", is to add the letter "n" followed a number that represents the space between the rails...which although not common, might even represent a broad gauge "n5" (5 feet between the rails) but it's more commonly used to represent narrow gauge track...if the designation is HOn3 this is HO scale with a track gauge of 3 feet. and so with any scale Sn3, On3, Nn3....even in in F scale......

[*] "F": represents the scale which is 1:20.3 Scale.....or 16mm = 1'-0" (about 9/16")

[*]F = without a trailing letter represents standard 4'-8 1/2" gauge prototype track, with 70mm gauge model track. [*]Fn2 = represents 2-foot gauge prototype track, with 30mm gauge model track. [*]Fn3 = represents 3-foot gauge prototype track, with 45mm gauge model track. [*]Fn3.5 = represents 3'-6" gauge prototype track, with 52mm gauge model track
In the above examples all represent the same scale which is...."F" which is 1:20.3 or 15mm = 1'-0" (about 9/16") [/list]
[/list]
 

·
Premium Member
Joined
·
584 Posts
RE: F scale D&SL 2-6-6-0 #212

Dean,
To nit pick further 16mm = 1'-0" is 1:19 scale as practiced popularly in Britain using 32mm track to represent two foot narrow gauge.
1:20.3 is closer to 15mm = 1'-0". They're probably out there but I don't know of anyone handlaying track in 30 or 52mm gauges but do know of some building 70mm standard gauge.
Further I always thought the sub n stood for narrow gauge so I'm not sure your broad gauge example is correct but then maybe it is. One more thing is On30, O scale on 30" gauge track vs On3 which might better be On36 but then I've never seen that either.
I normally model in 1:20 scale on 45mm track but both the portable live steam tracks I've built have 32mm/45mm dual gauge to accomodate as many steamers as possible. I just finished a 1:13 scale (7/8"=1') on 45mm gauge loco which I will unveil next week at Diamondhead, MS.
Paul is probably REALLY confused now!
Oh well, it's all fun,
Tom (definately not a rivet counter)
 

·
Premium Member
Joined
·
436 Posts
Discussion Starter · #12 ·
RE: F scale D&SL 2-6-6-0 #212

Thanks for the correction, I guess my old-timers is showing.....
 

·
Premium Member
Joined
·
2,269 Posts
RE: F scale D&SL 2-6-6-0 #212

Just at people say 1mm is .039" well its actually .03937"

I still would love to have a F scale std gauge to match my narrow gayge stuff.
 

·
Premium Member
Joined
·
4,393 Posts
Posted By Dean Whipple on 01/11/2009 1:03 PM

Steve not to nit pick....Well I guess I am.....I'm sure you know difference, but for those than may not know......


F is a scale which is a ratio 1:20.3 .....or 15mm = 1'-0" (about 9/16")

In all the other scales HO. S, O, even in N gauge the way to designate the gauge track that is other then the standard 4'-8 1/2", is to add the letter "n" followed a number that represents the space between the rails...which although not common, might even represent a broad gauge "n5" (5 feet between the rails) but it's more commonly used to represent narrow gauge track...if the designation is HOn3 this is HO scale with a track gauge of 3 feet. and so with any scale Sn3, On3, Nn3....even in in F scale......

[*] "F": represents the scale which is 1:20.3 Scale.....or 16mm = 1'-0" (about 9/16")

[*]F = without a trailing letter represents standard 4'-8 1/2" gauge prototype track, with 70mm gauge model track. [*]Fn2 = represents 2-foot gauge prototype track, with 30mm gauge model track. [*]Fn3 = represents 3-foot gauge prototype track, with 45mm gauge model track. [*]Fn3.5 = represents 3'-6" gauge prototype track, with 52mm gauge model track
In the above examples all represent the same scale which is...."F" which is 1:20.3 or 15mm = 1'-0" (about 9/16") [/list]
[/list]
Dean
I don't disagree with what you've stated (except for some minor dimensions, e.g. F = 1:20.32 per the NMRA spec.
).

The lack of my mentioning any of the various designation labels that are applied by various organizations, and groups of modelers around the world, wasn't an oversight but intensional. Additionally, I figured that limiting the discussion to track, it would be less confusing.

The point that I was trying to get across was, if you lock down one dimension (e.g. model track gauge, as we generally do in large scale) then the scale ratio has to change when using that dimension (i.e. 45mm) to represent the various prototype gauges that exist/existed.

On the other hand, if we lock down the scale ratio (e.g. 1:20.32) then the gauge of the model track has to change, just like the prototype does in the real world.

To me, if an individual can get their mind around those two concepts and feel comfortable with them, because they will always remain consistent. Then all the other alphabet soup of designations they'll encounter can be handled easier.

The one other thing that would most likely be helpful, is the fact that in some cases there is a certain fudge factor (plus or minus) applied to the scale ratio, for someone's ease of convenience.
 

·
Premium Member
Joined
·
2,195 Posts
Well, here we go again... I'm sure that we have managed to intimidate some of the newbies with all of the ratios and gauges (out to the nth decimal...) Getting back to the gist of this little deviation from the thread, the point 3 in 1:20.3 doesn't refer to the gauge of the track being represented. As to the rest, F is a legitimate scale being represented by the ratio of 1:20.32 as per NMRA standards and bringing the thread back to the original topic, that 2-6-6-0 is gorgeous!!
 

·
Premium Member
Joined
·
4,393 Posts
Posted By Steve Stockham on 01/12/2009 5:49 AM
Well, here we go again... I'm sure that we have managed to intimidate some of the newbies with all of the ratios and gauges (out to the nth decimal...) Getting back to the gist of this little deviation from the thread, the point 3 in 1:20.3 doesn't refer to the gauge of the track being represented. As to the rest, F is a legitimate scale being represented by the ratio of 1:20.32 as per NMRA standards and bringing the thread back to the original topic, that 2-6-6-0 is gorgeous!!
That sir I can not agree with.

The uppercase 'F' is in fact nothing more than an arbitrary label that was chosen to use instead of actually stating the scale ratio.

Further more, as happens many times things sort of happened in reverse. In the case of what eventually came to be labeled 'Fn3' scale (1:20.32) under the NMRA - General Standard Scales S-1.2 (Approved July, 2004) (Remarks Column - see note 2, which references #1 Gauge track (i.e. 45mm)).

Originally began with modeling 3-foot narrow gauge prototypes on #1 Gauge model track (i.e. 45mm gauge). If you divide the gauge of the prototype track (i.e. 36"), by the gauge of the representative model track (i.e. 45mm, converted to its equivalent inch measurement) and round the result to two decimal places, the result is 20.32, thus the scale ratio is 1:20.32 and that is what the letter 'F' is being used to represent.

The next step in the sequence, was the NMRA decided to include what has generally come to be referred to as 'large scale', in their Standards. Since in most cases of their standards the base scale designation (i.e. in this case 'F') represents that particular scale ratio (i.e. 1:20.32) as it relates to the prototype Standard Gauge track (4'-8 1/2" gauge) and its associated equipment. This would result in a model track gauge of 70.62mm (2.781") using the defined scale ratio of 1:20.32.

Addressing the usual convention used when discussing the suffixes appended to the base scale designation. The lowercase letter 'n' denotes the fact that the scale ratio is being used to represent a prototype track gauge that is narrower than the Standard Gauge (i.e. 4'-8 1/2") prototype. Next the numbers following the lowercase alpha suffix, express the prototype track gauge being represented in either whole feet, or whole inches (e.g. n3 = 3-foot gauge, n30 = 30-inch gauge).

Additionally, addressing a point that Dean raised above, the case of modeling what is generally referred to as Broad Gauge (i.e. railroads where the prototype track gauge was larger than 4'-8 1/2"). If this were to be included within the standards, to maintain consistency I would think the proper lowercase alpha suffix to use would be a lowercase 'b', and continue to use the convention of expressing the track gauge in whole feet or whole inches. Thus a Broad Gauge prototype of 5-feet would be expressed as 'Fb5', and a Broad Gauge prototype of 5 1/2' feet would be expressed as 'Fb66'.

In so far as your statement...
"Getting back to the gist of this little deviation from the thread, the point 3 in 1:20.3 doesn't refer to the gauge of the track being represented."
You're correct, in so far as the '.3' doesn't refer directly to the track gauge, it refers to the scale ratio, but the scale ratio defines the gauge dimension of the model track, and the level of precision that the model track, and any models of equipment, adheres to in its representation of the prototype. Because the scale ratio defines the linear measurement that represents one scale foot (i.e. 12 / 20.32 = 0.59" (approx. 9/16")). Note, some individuals also round this value to the nearest tenth of an inch (i.e. 0.6) so they can use an engineering rule graduated in tenths of an inch.

Finally, I don't agree with this aversion to discussing the concept of scale ratios and proportion with individuals new to the modeling hobby realm. Since it's the foundation that all of what's done in modeling rests upon. Once those concepts are understood all the rest of the alpha-numerical soup they'll encounter falls in place rather nicely, with a little explanation of what the various designations represent.
 

·
Premium Member
Joined
·
2,195 Posts
Steve,
What part of my statement don't you agree with? The scale ratio for "F" is 1:20.32! That's what I said and that's what you appear to be saying! What's to disagree with? F is a legitimate scale (in my opinion and in many others.) Please re-read what I have posted and I believe you will see that we actually are in agreement on this. As to discussing scale ratios and gauge widths, I love these discussions but it seems as if by doing so we are hijacking this thread. Just my opinion.
 

·
Premium Member
Joined
·
4,393 Posts
Steve

If that's what you meant by what you said then I guess we do agree, but it sure didn't come across that way when I read it, maybe it was just me.

By the way, I did forget to mention in the previous reply that I did agree with your statement that that is going to be one beautiful standard gauge locomotive in 1:20.3 scale, it's going to dwarf anything else that runs on #1 gauge track.
 

·
Registered
Joined
·
11 Posts
RE: F scale D&SL 2-6-6-0 #212

Hello Gentlemen,

It's been a pleasure making parts for George--it just takes a lot of time to CAD up various bits and pieces and then cut them out on the EDM. Some of the parts have been very fiddly--for instance the lead truck components--but George had done a good job putting them together.

I rather wish some of the rest of you all would get interested in building a 1:20.32 standard gauge locomotive. I'd be open to sharing parts and expenses if someone wanted to build a loco with me (I already three in various stages of construction). It's usually more fun and more motivating to have a collaborator!

Why "F" scale? Well, maybe the NMRA guys did this on purpose, maybe not, but in metrics, 1:20.32 is the same as 15mm = 1 foot, so "F" is a convenient abreviation for "fifteen."

As far as the exact track gauge for "F Gauge" is concerned, there is of course an upper and lower limit on the tolerances. That lower limit is 70.64mm (2.781"). The upper limit is 2.842". When Don Niday and I had the mold for the plastic tie strip made, we settled on a nice round inbetween number of 2.8" for the gauge. All the more recent roller gages that we sell gage the rails to that figure. But it's not that critical: Anyone who can handlay to .010" has my hat off to him.

Cheers!

Dave Queener
www.CumberlandModelEngineering.com
 
1 - 20 of 28 Posts
Top