Hello,
This is my first post here… In recent articles in MRR magazine, the scale HO is referred to as being 1:87.1? Why not 1: 87, which has been in use for decades? Could someone please enlighten me - Thanks.
Michael
Welcome to the forums.
From an earlier thread on the same question:
Stein
Thanks Stein.
Before calculators (yes, there was such a day), it was much easier to work with scales expressed as “so many units on the model represent so many units on the prototype” rather than ratios. This was true across all types of modeling and all types of scale drawings in engineering. 1/4" = 1ft (North American O scale), 1/10" = 1ft (TT scale), 3/16" = 1ft (S scale) are common scales used in architecture as well as modeling.
The European toy train makers defined gauges before scales were in use. Scale wasn’t important as making sure everything ran on the same track gauge. 0 gauge (later became O instead of Zero) was set at 32mm or 1.25" - I’m not sure which was the original. The Brits, in their lovable way , mixed metric and English units, and assigned 7mm/ft as the correct scale for O gauge track. Note that 7mm/ft is closer to correct scale than the more approximate North American 1/4"/ft.
As stated in my earlier post, Half O became 3.5mm/ft, and later became HO. The track gauge was corrected to 16.5mm instead of 5/8" or 16mm, which were sometimes used in the early days.
When ratios became the more favored way of expressing scales, there are actually 2 ways to run the calculation. One is taking the scale (3.5mm/ft) and computing the ratio, which gives
A modeling scale of 1 to 87.1 makes as much sense as a guage of four feet, eight-and-a-half inches. Someone, way back when (around 1800), could have at least rounded it to the nearest inch. And those were Englishmen who were not converting measurements from the metric system.
Mark
When measuring I still use 3.5mm to the foot because my antique HO ruler uses 3.5mm…
Like Mark I never could understand why some goofball change 35mm to 1:87.1…After all 3.5mm still works.
Fred wrote:Final note is that N and Z scales were developed after ratios had come into common use. N scale ended up being defined as 1/160 rather than as units/units.
Fred,A tidbit for you. Actually in 1960 N Scale started as 9mm and was changed to 1/160th…
Depends. If you are modeling 1/4" scale and the gauge is 1/4’ scale then N American 1/4" scale is more accurate. 7mm/ft is closer, but still is just a rounded off approximation.
Well the problem with “quarter inch scale” as they used to call it is that if the track is 1.25" wide, then it measures 5 feet, not 4’-8 1/2". To be correct you can change the linear scale - in the US in the thirties and forties some prominent O gaugers used 17/64" = 1 foot which was much closer to being correct. In recent years a few modellers have narrowed the track gauge so that it measures the correct 4’-8 1/2" gauge in 1:48 scale.
But for now it appears most US O gaugers are going to continue to use slightly undersized 1:48 scale equipment. One problem that brings up is that so many figures and automobiles are made in Europe, and are proportioned to 1:43.5 scale, so look big compared to our undersized 1:48 scale stuff.
Still, O probably is more unified than “Big Scale” G gauge (which is really No.1 gauge) which has numerous different scales that use the track…1:32, 1:29, 1:24, 1:22.5, and 1:20.3 and maybe others.
[%-)]
That whole HO roundoff thing just drives me nuts. I’ll see a building that looks out of scale next to locomotive, then realize that the building is 1/87 but the loco is 1/87.1, and that explains it. [D)]
The rounding difference between 1/87 and 1/87.1 is insignificant and not discernable in almost every case. Take a door, we’ll assume it’s 87 inches high in real life, which means 1 inch actual height in HO. The 87.1 means it’s less than 0.115% over or under size, and not detectable without a scale ruler.
Even on a model of an 87 foot passenger car the difference amounts to a scale or full size 1.2" - again not detectable without measuring.
Where rounding does make a difference is using 0.011" to represent 1 scale inch in HO. The correct measurement is closer to 0.0115", but most of us don’t measure to the 1/10,000 of an inch. Now, you are looking at a 4.5% error in scaling, which just might be detectable by a trained eye.
Many “HO scale” structures are not even close to HO scale - if any scale was used at all - and that’s why they look out of place. Foreground trees are another sore subject with me. How many 20ft trees do you see along a railroad right of way? Yet that’s what is commonly sold. Many/most foreground trees are at least 40ft high, which means they need to be at least 6" actual height in HO.
my thoughts, your choices
Fred W
The numerical ratio that comes from equating the scale is irrelevant when trying to make sense of it. It’s just the product of the equation.
Using 4ft 8.5inches does make sense as that was an existing measurement which became a standard. Much like using the Kings Rule to determine what a ‘foot’ of length was, which to us became a standard at some point and has been that exact length since that point in time(to convey my point, why 12" and simply not 10"? Base 10’s are easier to compute and work with).
4ft 8.5inches isn’t arbitrary, or created on a whim as a “Hey lets just make it this wide” moment. Sure, somewhere along the way they could have increased or decreased it a half inch. But why? For the simplicity of saving a few syllables when stating the exact width of standard gauge railroad track?
Maybe because the rest of the world is metric…Even the British is metric now, it´s only you in the US left.
And besides that it isn´t good to mix measurements.
That´s because the standard gauge is based on the standard roadlane width, started by the Romans with the stone roadways that had almost the exact same C/C measurement.
Michael, Canada originally used the Imperial (British) system of measurements but in 1970 began converting to metric. A slow process, seemingly not yet complete, we have a variety of Imperial measurements still in use (in the building industry, for example. Temperature and distance are metric (both a regression in my opinion), as are weights.
However, volume/capacity is still in a state of flux. We originally had gallons and quarts, etc. Gasoline, formerly sold in Imperial gallons (4.55 litres) is now sold by the litre. However, oil for your car, formerly sold as an Imperial quart (1.14 litres), remained for some time to be sold in the same containers, which were simply re-labelled to show the contents as 1.14L. Sometime later, motor oil (and other by-the-quart commodities) began to appear in one litre containers, seemingly completing the switch-over. Unfortunately, this was later replaced by the .946 litre container, which, coincidentally, is the same as a U.S. quart. The price, by the way, if it changed, certainly wasn’t in the downward direction.
For older Canuckleheads like me, we’re still trying to figure out why the darn quart seems to keep getting smaller. [%-)] For those kids who grew up learning the metric system, they probably haven’t even noticed the latest change, and if they have, couldn’t care less. [sigh] And for the few American tourists who still venture north for a week of skiing in July, they’re probably saying, “.946 what??” [;)][(-D]
Wayne
The US is one of the original signatories to the 1875 treaty that codified the metric system. We are a metric country, we just choose not to use it. Although we print it on everything. Ever actually look at the nutrition facts on a food box? Not a single Imperial measurement on there. Except for calories.
But then everyone except the countries that used to have a lot of red flags and hammers and sickles use feet in aviation. Go figure.
Saw a lot of juniper trees along the right of way that size and smaller. The pinons were about the same size. Maybe it’s time to model a juniper/pinon forest. (can’t do the wave over the “n” in “pinon”)
Mark, on a snowy late-May day in Arizona; view from the observation car
You have to be kidding, right?
Absolutely! It’s utterly my point - who really cares whether it’s 86.92 or 87 or 87.08? I mean, c’mon. We’re talking about a difference of 1 inch over 100 feet. Seriously…
I think the OP saw it and was just looking for information/education. Looks like he got the info.
Someone out there must care though if it’s referred to that way. I’m not one of them.[:)]
The story about the Roman carriages determining the British, and many other subsequent rail gauges, is not true. It is handy, intuitive, and oft repeated, but it is not true.
-Crandell
I thought the rail gauges were a result of a Drunk that passed out. Rather than move or try to wake him the rail crew placed the rails around him. [:-^]
And while we are on the subject. [:-^]
Does anyone make a gauge to measure say, a piece of bass wood and convert it to HO gauge inches? My brain is slow. [%-)]
Thanks
Lee