The mystery of "Gauge"


Redrider

Member
Obviously since I posted this in the O gauge area of "Scale specific discussions", I am going to concentrate on O gauge or O scale as a definition. I've been told in the past that Gauge means one thing and Scale means another. I've also been told that both counter act one-another. One refers to track width, the other refers to sizing of the various items present in a layout. One starts with a G and the other starts with an S.

I have seen in person, not just YouTube, very few train layouts. My favorite so far is the Colorado Railroad Museum. Why? Size. The thing covers an entire warehouse. Along the way there are all kinds of displays involving lumber yards, lighted signs, tunnels that go east when you enter and west when you come out the other side, a lot of work went into this. Not to mention the electrical set up that had to be figured out to make it all work.

However. The dreaded however. Praise the layout then send it to its room for getting a B instead of an A. Scale integrity along the route, as I watched through the lens of a camera placed in the various cabs of the locomotives, seems to always take on an air of necessity, rather than an air of detail integrity. Lionel, MTH, Atlas, Bachmann, whoever makes Locomotives, Rolling Stock, Track, Buildings, People, Signs, and the various carnival rides and moving pieces props they wish to sell to the public, attempt to keep with scale integrity. O scale, as I have come to know it, unless I'm wrong or naive, is 1:48. 1 (inch) on a typical measuring device, equals 48 inches in the O scale system. So one inch equals four feet. Simple. I guess. Based on that, two inches equals eight feet. Yes? No? Maybe? In my experience, just throwing this out there, it appears to be more "guidelines". Model Railroaders in some situations can't possibly stick to the system due to sizing conflicts among the other scale model industries. The company's that make scale model tractors, backhoes, cars, trucks, motorcycles, etc. follow a similar doctrine, but not an exact doctrine. 1:43, 1:50, 1:64. Even when they do, the occassional 1:48 scale Trackhoe or Crane, they almost appear to be the same size as the flat car they would ride upon.

One layout I saw on YouTube, which was phenomenal, moving pieces I'd never seen before. Kid climbing a tree, welder repairing a track, smoke and all, guy unloading 4x8 sheets of plywood. Then I'd see a fire truck that was as big or bigger than a locomotive. I've never once seen an O gauge or O scale layout that had a Tonka dump truck sitting in the middle of it, but I have seen my share of layouts that obviously threw caution to the wind when it came to how big the car waiting at the crossing was in comparison to the train going by.

What's my end game in all this? I want to know if anyone else out there who has a train layout of whatever size attempts to stick to the O the same way I do. Granted my water tower is probably not to code, but I also do not have a G.I. Joe action figure working on my loading dock.
 
Generally. 1:48. Is accepted as o scale. Just like g gauge. There are a bunch of scales that fit onto o gauge. Then there is postwar. I am not including narrow gauges in this line 009. Sticking to a specie scale for a gauge is one aspect of the hobby. Trying to be all of a specific scale. That can go to an extent called proto modeling. Or p48. P87. P4. P9. And such. To name a few scales. Nothing wrong with working in that direction. Keeping everything scale. Except for the occasional giant spider.
 
This is just my opinion, and maybe some others too, but I try to categorize "O" into two distinct categories.................. O-scale, and O-gauge.

O-scale: Just like HO-scale, N-scale, etc., etc. Everything one single scale size (i.e., 1/48, or 1/87, or 1/160, etc.), and 2-rail, just like the prototype. Usually straight D.C. powered. And true, single scale fidelity is important. As far as I'm concerned, O-scale has far more in common with HO and N-scale model trains than it does with 3-rail O-gauge.

O-gauge: I lump all 3-rail, Lionel-type trains into this category, because scale sizes can be all over the place, but the trains still run on 3-rail, O-gauge track, which is 1-1/4" gauge between the rails. Scale sizes generally range from 1/48 to 1/64. But they can go smaller, or can be larger, too. A.C. transformers are virtually the universal standard. Scale fidelity is more of a suggestion than an absolute mandate, and 3-rail track that can have ridiculously small radii kind of emphasizes that in a not-so-subliminal sort of way.

So to sum it up in a nutshell, when it comes to 1/4" scale trains, I try to remember it like this:
O-scale = 2-rail, exact scale, D.C. powered.
O-gauge = 3-rail, sorta' scale, A.C. powered.

Hope this helps a little in, and makes some sense of, understanding the crazy world of 1/48 (more or less 🤪) 2-rail and 3-rail trains!
 


This is just my opinion, and maybe some others too, but I try to categorize "O" into two distinct categories.................. O-scale, and O-gauge.

O-scale: Just like HO-scale, N-scale, etc., etc. Everything one single scale size (i.e., 1/48, or 1/87, or 1/160, etc.), and 2-rail, just like the prototype. Usually straight D.C. powered. And true, single scale fidelity is important. As far as I'm concerned, O-scale has far more in common with HO and N-scale model trains than it does with 3-rail O-gauge.

O-gauge: I lump all 3-rail, Lionel-type trains into this category, because scale sizes can be all over the place, but the trains still run on 3-rail, O-gauge track, which is 1-1/4" gauge between the rails. Scale sizes generally range from 1/48 to 1/64. But they can go smaller, or can be larger, too. A.C. transformers are virtually the universal standard. Scale fidelity is more of a suggestion than an absolute mandate, and 3-rail track that can have ridiculously small radii kind of emphasizes that in a not-so-subliminal sort of way.

So to sum it up in a nutshell, when it comes to 1/4" scale trains, I try to remember it like this:
O-scale = 2-rail, exact scale, D.C. powered.
O-gauge = 3-rail, sorta' scale, A.C. powered.

Hope this helps a little in, and makes some sense of, understanding the crazy world of 1/48 (more or less 🤪) 2-rail and 3-rail trains!
All of this is great information. I am always looking for any information that helps me understand how model railroading works. I don't live in a location where model train stores are popular. Therefore I don't have a library of human contact to bounce my ideas and opinions off. And to anyone reading this reply, they are just ideas and opinions, I do not now nor never will consider anything I type to be "the way". This is the way it has to be done. All of it is just my opinion, how I see it, and, more important, an opinionated way of asking, "is this correct?" Plus I like to talk to people who have common interest. I like the sorta scale/exact scale example.
 
There's a ton of O Gauge models that aren't remotely to any actual scale, and are virtually disqualified from being considered "O scale".
 
Strictly speaking, "Scale" refers to the relation of a model to the prototype. "Gage" refers to the distance between the inside of two rails of a track. Since I model in HO scale, I will refer to dimensions in that size. Now in most U.S. and British prototype railroads, "Standard Gage" is 4' 8-1/2" between the inside of 2-rail track. We usually refer to HO scale as 87.1:1, which isn't quite true because HO is actually in metric (which I can't convert to right now). At 1/87.1, the gage between the rails should be .64867", but the piece of flex track I measured comes out to .634", which equals 4' 7-1/2", which is just a little off...unless the scale ratio isn't quite 87.1. That doesn't quite bother me, as it has become the industry standard for HO for years, and I can't quite eyeball the difference. As far as the scale sizes of various cars, trucks and other models are concerned, the various manufacturers have decided how close they can get to a particular scale, depending on their tooling capabilities. When I select a particular model of such items, it will depend on how I think it looks without being too terribly out-of-scale.

So there will always be some compromise. Is HO scale exactly half of O scale? No, it isn't. It is slightly off, perhaps OO scale, which is what I believe is a standard in Great Britain. Anyway, I do go by the "rule", it is YOUR model. Have fun.
 


Late to the party, yes the terms gauge (preferred spelling) is the distance between the outside rails, and scale is the proportion to the real thing.

It is amazing how something that should be simple and straight forward gets so complicated. And how long winded this message got to be.

The reason (as far as I know) that gauge was used for O, is that the first trains were not even intended to be built to scale and the 3-rail AC system. But the gauge between the outer rails was a consistent 1-1/4 inches, so that was what you needed to run on i.e. O-gauge track so they were O-gauge trains. Also some equipment was built short on purpose, passenger cars being a well known example. They needed to be short to negotiate the tight curves. And if you had adjacent tracks going around a curve and the car was scale length the overhang would cause them to hit. Today the main difference between O-gauge and O-scale trains (at least for the rolling stock) are the couplers and trucks. Some manufactures realize they can sell more equipment by building the model body to scale and allowing the modeler to choose the 3-rail trucks and couplers or 2-rail scale trucks and couplers.

Even the first O-scale trains were built with an outside 3rd rail and shoe on the locomotive for power, not sure if they were AC or DC powered, maybe some older modelers in my club know.

As for HO being half-o yes it comes from the UK O-scale which is 1:43.5 and half of that is 1:87, now I guess someone did some measuring and found out that something track gauge? car length? didn't scale out correctly so 1:87.1 is correct for HO scale. Which someone figured that translates to 3.5mm on scale equipment is 1 foot on the real thing, yeah lets mix imperial and metric units why not?

There was some mention of the Proto scales (P48, P87, etc) that is because someone realized that the rail & wheel profiles were too big if you scaled it up and for O the gauge of 1-1/4" inches between the rails scales up to 5 feet, not the prototype 4' 8 1/2" it should be. The reason for this is the O-scalers in the US took existing O-gauge equipment mechanisms and converted them to scale. For HO the code 100 rail that was so popular scales up to 155 lb/yard rail which was/is? only in use on the North East Corridor.

People do run DCC as well as DC power in O-scale 2-rail. Because of the interchangeable use of O-scale and O-gauge there are more abbreviations that help distinguish what you are talking about: OS2R (O-scale 2-rail) and O3R (O 3-rail) and for O-scale 3 rail: OS3R (or 3RS)

N has a similar problem as the gauge (distance between the rails) is nine millimeters. So depending upon the manufacturer (or country), the scale ranges from 1:148 to 1:160. Effectively the scale is 1:159, 9 mm to 1,435 mm (4 ft 8+1⁄2 in). Japan uses 1:150 as the scale, U.S. uses 1:160 and UK uses 1:148
 
Great information. Thanks! So far as O-gage being 5 feet between the rails, that would be correct for anyone modelling one of the Southern or maybe some Eastern railroads in the mid-19th Century, before most roads went to standard 4'-8-1/2" gage. (I will still use the more convenient spelling for "gauge".)

Oh, as far as the HO Code 100 being equivalent to 155 lb/yd is concerned, I'm not even sure that Code 85 isn't a bit heavy for most of the original mainline roads. But due to the need to handle "cookie-cutter" wheel flanges on the earlier models, as well as Code 100 being a bit easier for us old codgers to handle, I guess we will have to live with it.

Thanks, again!
 
Late to the party, yes the terms gauge (preferred spelling) is the distance between the outside rails, and scale is the proportion to the real thing.

It is amazing how something that should be simple and straight forward gets so complicated. And how long winded this message got to be.

The reason (as far as I know) that gauge was used for O, is that the first trains were not even intended to be built to scale and the 3-rail AC system. But the gauge between the outer rails was a consistent 1-1/4 inches, so that was what you needed to run on i.e. O-gauge track so they were O-gauge trains. Also some equipment was built short on purpose, passenger cars being a well known example. They needed to be short to negotiate the tight curves. And if you had adjacent tracks going around a curve and the car was scale length the overhang would cause them to hit. Today the main difference between O-gauge and O-scale trains (at least for the rolling stock) are the couplers and trucks. Some manufactures realize they can sell more equipment by building the model body to scale and allowing the modeler to choose the 3-rail trucks and couplers or 2-rail scale trucks and couplers.

Even the first O-scale trains were built with an outside 3rd rail and shoe on the locomotive for power, not sure if they were AC or DC powered, maybe some older modelers in my club know.

As for HO being half-o yes it comes from the UK O-scale which is 1:43.5 and half of that is 1:87, now I guess someone did some measuring and found out that something track gauge? car length? didn't scale out correctly so 1:87.1 is correct for HO scale. Which someone figured that translates to 3.5mm on scale equipment is 1 foot on the real thing, yeah lets mix imperial and metric units why not?

There was some mention of the Proto scales (P48, P87, etc) that is because someone realized that the rail & wheel profiles were too big if you scaled it up and for O the gauge of 1-1/4" inches between the rails scales up to 5 feet, not the prototype 4' 8 1/2" it should be. The reason for this is the O-scalers in the US took existing O-gauge equipment mechanisms and converted them to scale. For HO the code 100 rail that was so popular scales up to 155 lb/yard rail which was/is? only in use on the North East Corridor.

People do run DCC as well as DC power in O-scale 2-rail. Because of the interchangeable use of O-scale and O-gauge there are more abbreviations that help distinguish what you are talking about: OS2R (O-scale 2-rail) and O3R (O 3-rail) and for O-scale 3 rail: OS3R (or 3RS)

N has a similar problem as the gauge (distance between the rails) is nine millimeters. So depending upon the manufacturer (or country), the scale ranges from 1:148 to 1:160. Effectively the scale is 1:159, 9 mm to 1,435 mm (4 ft 8+1⁄2 in). Japan uses 1:150 as the scale, U.S. uses 1:160 and UK uses 1:148
Welcome to the forum. I see you are a new member. Glad to have you aboard! 👍
Are you trying to make trouble? 😁
 
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Fantastic information, thank you. Now that you tell me again, I'd read that part about gauge and scale somewhere else, it makes perfect sense as far as "what does gauge mean and what does scale mean."

Sorry for the long wind in my posts, but I come from a job years ago where communication between myself and my supervisors, yes, visors, not visor, was an endless stream of emails because the two of them just wanted "the facts maam". (Dragnet, Joe Friday). I'd send a war and peace email (length not content) and all I'd get back as an answer to my question was "you type too much". So I'd give them just the facts, and 400 emails later they would have asked all their questions. I answered all 400 of them in my first email.

I like to make sure my audience is fully aware of what I am asking before I send the question. In this case we kind of got off track, pardon the pun, but the information has been gold.

Thanks to all of you for your input, this is a great site for a newby who is just trying to learn how all this works. I've been doing this for 8 years and I still have questions. Mostly about why trains stop working for no reason I can decipher, and why train companies keep pouring out the same "new" stuff every year that looks incredibly like the new stuff they poured out last year.

As for the "off track" remark. I just wanted to know if it was just me who noticed that O scale, thank you, was being used as a guideline more than a standard in train layouts.
 
Great information. Thanks! So far as O-gage being 5 feet between the rails, that would be correct for anyone modelling one of the Southern or maybe some Eastern railroads in the mid-19th Century, before most roads went to standard 4'-8-1/2" gage. (I will still use the more convenient spelling for "gauge".)

Oh, as far as the HO Code 100 being equivalent to 155 lb/yd is concerned, I'm not even sure that Code 85 isn't a bit heavy for most of the original mainline roads. But due to the need to handle "cookie-cutter" wheel flanges on the earlier models, as well as Code 100 being a bit easier for us old codgers to handle, I guess we will have to live with it.

Thanks, again!
Yes, but even 5 feet is too narrow for some railroads, or parts! Erie had a section that was 6 feet! And Wikipedia says a majority of the rails in the South were converted over two days of May 31 – June 1, 1886, but only down to 4' 9 inches!

Have always heard the term pizza cutter flanges for the way over scale flanges that will only run code 100 track. But, I guess cookie cutter works too.

Yes code 83 rail in HO is still a little on the heavy side, but closer to prototype. I'm sure a P87 guy will tell how the rail profile is wrong too along with wheel tread width and profile.

Welcome to the forum. I see you are a new member. Glad to have you aboard! 👍
Are you trying to make trouble? 😁
Maybe I should have started with a less "controversial" subject. ;)

We just have to accept that gauge and scale are used interchangeably in O and maybe N as well, although I think less so.
 




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