Model Railroading > HO Scale Miles

How many feet of track comprise one scale mile(HO Scale)?
Thank you,

Hal

60' 8 1/4". Take 5280 (feet per mile) and divide by 87.

I always remember one scale foot equals 3.5mm, so times the number of feet by 2.5 convert from mm to ft and there is the answer, 60.6 ft.

Thanks for doing the math for me.
I just didn't think of the obvious solution of dividing 5,280 by 87.

Hal

For ease of memory, 60 feet is a reasonable approximation -- especially recognizing that most home layouts will struggle to have more than a scale mile or two of main line!

A little more accurate would be to divide by 87.1.

alaska Wrote:
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> Thanks for doing the math for me.
> I just didn't think of the obvious solution of
> dividing 5,280 by 87.
>
> Hal

wabash2800 Wrote:
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> A little more accurate would be to divide by
> 87.1.

Explain?

toledopatch Wrote:
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> wabash2800 Wrote:
> --------------------------------------------------
> -----
> > A little more accurate would be to divide by
> > 87.1.
>
> Explain?


Because, as Warren already mentioned, HO is a metric scale, 3.5 mm = 1 ft. thus scale is actually 87.1 to 1.

Elizabeth

HO is simply 1/87 scale. It's 1 whatever in scale equals 87 whatever in the real world, doesn't matter if it's feet, millimeters, cubits, or skin follicles.

I don't understand how it being a metric scale plays into anything at all. O gauge which is what it was based om was surely not metric when it came out since metric was barely even in the lexicon at that time.

MagnumForce Wrote:
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> HO is simply 1/87 scale. It's 1 whatever in scale
> equals 87 whatever in the real world, doesn't
> matter if it's feet, millimeters, cubits, or skin
> follicles.
>
> I don't understand how it being a metric scale
> plays into anything at all. O gauge which is what
> it was based om was surely not metric when it came
> out since metric was barely even in the lexicon at
> that time.


I was kind of wondering where this "metric scale," um, concept came from, too -- some Marklin thing?

MagnumForce Wrote:
-------------------------------------------------------
> HO is simply 1/87 scale. It's 1 whatever in scale
> equals 87 whatever in the real world, doesn't
> matter if it's feet, millimeters, cubits, or skin
> follicles.
>
> I don't understand how it being a metric scale
> plays into anything at all. O gauge which is what
> it was based om was surely not metric when it came
> out since metric was barely even in the lexicon at
> that time.

3.5 mm (0.14 in) represents 1 real foot (304.8 mm). This ratio works out to about 1:87.086.

BTW, the metric system has been around since the 1790s.

Elizabeth

There is no known cure for willful ignorance.



Edited 1 time(s). Last edit at 10/03/10 17:44 by Betsy.

Since when? I have never heard this before in my life!

1 inch represents 87 inches
1 mm represents 87 mm
1 foot represents 87 feet
1 Km represents 87 Km

Perhaps the 3.5 is what is extrapolated after the fact as it gives a measurement within a hundredth of a foot which is pretty darn close, but HO means 1/87th scale. Plain as that!

While the metric system has been around since the 1790's it did not come into widespread use until the mid 20th century.

EDIT: I do realize that the metric system was made official long before this in other places but in Early 20th Century US it was barely in the lexicon! For all I know you might be right, it's just that it's hard to go against what you have known your entire life. The 3.5 mm to the foot thing just seems like a convenient measurement to me more then what was originally envisioned.



Edited 4 time(s). Last edit at 10/03/10 17:57 by MagnumForce.

And while I don't deny that the metric system has been around for a long time, who established the "metric ratio" for HO scale? I have always understood it to be 1:87 scale as well; the 3.5mm = 1 scale foot factor strikes me as something cooked up for people who live in areas that have adopted the metric system, not the other way around.

I agree with Betsy. Do a little research. 1:87 is a convenient approximation. Check at nmra.org.

An easier solution is to switch to O scale because dividing by 48 is much easier.

I have a Headache......

I'm going home now.

Betsy,
You are right on scale ;),

Gary

Sorry guys.... The NMRA says HO is 1:87.1. That's as official as you can get in the old USofA unless you can get Congress to pass a law.

Barry Draper

But they goofed on the track gauge unless you are modeling Proto 48. <G>

rehunn Wrote:
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> An easier solution is to switch to O scale because
> dividing by 48 is much easier.

rehunn Wrote:
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> An easier solution is to switch to O scale because
> dividing by 48 is much easier.

LOL, as long as you're modeling Russian broad guage. 1.25" track guage is 5', and not 4' 8-1/2".

NMRA Standard S1.2 defines general scales:

http://www.nmra.org/standards/sandrp/pdf/S-1.2%202009.07.pdf

The scale is 1 foot = 3.5 mm, or 1/87.1. Now, if you want to model 1/87, go knock yourself out. Your wheels have oversize flanges, are too wide, and even if you're using Kadee "scale" couplers, well, real couplers don't have shiney brass knuckle springs and trip pins. Also, your 1/4" wide draft gear boxes are nearly twice as wide as the real thing. So if you're happy with all these other compromises, by God, you have every right to model in an approximation of the scale as well. Why bother with fine scale models if you're only going to use tinplate-like trucks and couplers?

Fine and Proto scales are given in NMRA standard S1.1:

http://www.nmra.org/standards/sandrp/pdf/S-1.1%202009.07.pdf

As far as the scale relationship, they are the same as S1.2. 1 foot is 3.5mm or 1/87.1. The minimum guage for all three is the same. 0.649". Maximum guage gets sloppier as you progress from Proto87 (0.663") to Fine Scale (0.665") to standard HO (0.672"). Other details like flangeways change, too, but that's getting into the weeds for this discussion. Point is, any way you slice it, HO is 1/87.1 scale.

- Arved

I do model Proto 48, trying to make sense out of scale using 1 1/4" track gauge gave me a headache!!