Specifying Scale & Gauge

[Ron Solly]

Thanks Martin for the clarrification.

[TT3]

TT would be fun too, 3 different scales (UK, US and Eu and also 3 gauges 12, 13,5 and 14.2).

 

Even if you could standardise the standard gauge scales, narrowgauge is something else entirley and far more complex...what with the American scales, H0n3, 0n30, Sn3 and so forth... sure you have the scale but the guage is the prototype far from the UK 009, 0-16.5....then we dont even ask about large scale work such as 'g' scale (32 or 45mm depending on preference) and SM32... I know a few large scale modllers who like the american idea of altering scale/ratio to suit track gauge....'yes it is realy 1:17.5 so it runs on 3'6"...'

 

,

[Guest jim s-w]

Hi All

 

The problem with all this 76/16.5 stuff is its already wrong! After all 4mm scale is NOT 1:76 but 1:76.2 If we are talking about clarifying things for accuracy why use a number thats wrong?

 

Cheers

 

Jim

[Bob Reid]

Hi All

 

The problem with all this 76/16.5 stuff is its already wrong! After all 4mm scale is NOT 1:76 but 1:76.2 It we are talking about clarifying things for accuracy why use a number thats wrong?

 

Cheers

 

Jim

 

Very Good Jim ! So P4 would be 76.2/18.83-19.05 (on 528mm radius) Nah what's wrong with P4 - If you're that interested one of the first things you'll find out is the scale & gauge. No?

[martin_wynne]

Does it matter if someone doesn't know what "00 Gauge" means?

[Ron Solly]

Does it matter if someone doesn't know what "00 Gauge" means?

 

No, just do what I did.

Google "00 Gauge" & find this http://en.wikipedia.org/wiki/OO_gauge and that is part of problem - with the internet , almost all questions can be answered by some searching but there are what I call "lazy" people who ask without looking first ( or am I too hard on them?)

[Guest jim s-w]

Nah what's wrong with P4 - If you're that interested one of the first things you'll find out is the scale & gauge. No?

 

You'd think that wouldn't you? After all if everything says 00 gauge on the packet you are pretty safe to assume its all the same scale and it will all fit together. If you want to scratchbuild something then looking up the scale is the easiest bit of research you will do on the whole project isnt it?

 

Good point about gauge widening BTW. Factor in that BR experimented with gauge to prevent hunting, and that you cant even rely on the good old 4ft 8 and a half inches gauge of the real thing being correct, and things get REALLY complicated!

 

Martin, does it matter? Not one bit no.

Cheers

 

Jim

[Guest jim s-w]

I call "lazy" people who ask without looking first ( or am I too hard on them?)

 

Not at all Ron. Its just that the thought of finding something out yourself never crosses the mind of some people. My favourite, how wide is a road? With exception of people living abroad, go out of your front door and measure the one outside your house!!!

 

Cheers

 

Jim

[Bob Reid]

Whilst I can see some merit in providing the additional information, I fear it's one of those occasions where an attempt to "modernise" scales & gauge nomenclature goes far too far away from what the original reason for applying the '00' 'P4' 'EM' etc. tags was. A classic case of thinking because somethings old it automatically must be cr@p and ripe for "modernisation" (Think The Re-Shaping of British Railways).

 

They were originally designed for simple identification primarily for the non-enthusaist buyer but also for the enthusiast too, as simple abbreviations as to what will run on what, to approximately the same scale and gauge - fundamentally that hasn't changed in all the years, and continues to be used worldwide and recognised as a quick reference as to compatibility - dare I say it, even exponents of P4 will look for '00' compatibility on the end of the box when choosing the next P4 conversion project.......(No I'm not son of Lucifer, on drugs or other mind enhancing products).

 

So in answer to the original question? No there isn't any need to change it. The old system with it's more modern additions still works.

[Ron Solly]

All of the above has been interesting but they may have been the cause of my question on Post #43 being missed so I have copied it again for possible answers. Yes I know I Googled it & tried but gave up after about 20 minutes. I relates to 00 in the main.

 

Also there seems to me to be much references to UK locos not having room for splashers, etc, so that affects steam outline- so is the modern UK diesel models affected - do they have the same problems? I am not aware of such problems with diesel models from Aust or USA or even Europe.

[Pennine MC]

Not at all Ron. Its just that the thought of finding something out yourself never crosses the mind of some people. My favourite, how wide is a road? With exception of people living abroad, go out of your front door and measure the one outside your house!!!

 

 

Measure it Jim? How do y'do that, then :icon_what:

[Bob Reid]

Measure it Jim? How do y'do that, then :icon_what:

 

With a piece of string?

[Bloodnok]

My favourite, how wide is a road? With exception of people living abroad, go out of your front door and measure the one outside your house!!!

 

Depends what you are trying to represent. I wouldn't recommend getting the tape measure out on the M25. That's a case where looking up the relevant standard online is probably a good idea . (FWIW Motorway lane width is generally 3.65m, but the left hand lane can be 3.75m - yep, the lanes are not always the same width...)

[martin_wynne]

Also there seems to me to be much references to UK locos not having room for splashers, etc, so that affects steam outline- so is the modern UK diesel models affected - do they have the same problems? I am not aware of such problems with diesel models from Aust or USA or even Europe.

Hi Ron,

 

If you measure any RTR H0 model over the running gear, outside cylinders, bogie side frames, axleboxes, whatever, you will find it overscale width in that respect.

 

This is because the wider RTR wheels, running on an exact scale track gauge, are wider across the outside faces than the prototype. Bogie side frames, splashers, outside cylinders, etc., all have to be pushed out wider than scale to make room.

 

This doesn't happen on any of the UK gauges, because in every case where overscale wheel profiles are used (00, EM, 0 gauge, etc.), the track gauge is reduced below scale to compensate.

 

This means that those who want to convert say an RTR 00 gauge model to P4 have an accurate bodyshell, bogie frame, whatever, to work from. They should give thanks for 00 gauge instead of so often declaring it to be wrong!

 

Whereas those wanting to convert RTR H0 to Proto87 are not so lucky. To create an accurate model means reducing the original width of a moulding somewhere. This would especially be the case for UK-outline steam models with splashers -- if there were any such in H0 to convert.

 

regards,

 

Martin.

[martin_wynne]

If we were starting now, with today's technology and manufacturing advances, there would be a very good argument for the UK RTR to be HO gauge.

Hi PMP,

 

No there wouldn't be. It is simply not sensible to use an exact scale track gauge unless you also use an exact scale wheel profile to go with it -- which is totally impractical for RTR models.

 

It is H0 which got it wrong, and the fact that the rest of the world adopted it does not make it right. It's no accident that the EMGS, the Gauge 0 Guild, etc. also specify a reduced track gauge for use with their overscale wheel profiles.

 

regards,

 

Martin.

[martin_wynne]

For ToyTrainMfgCoLtd/Corp/.com there is clearly a set of HO 3.5mm/ft scale, 16.5mm gauge manufacturing tolerances that work. If we were starting today those tolerances could be applied successfully to British outline models.

Hi PMP,

 

It depends what you mean by "applied successfully". Clearly they would run, and look ok as toys. But it is physically impossible for a UK-outline steam locomotive to be the correct width across the splashers if modelled at 3.5mm/ft and using the NMRA H0 standards. 00 gauge models can be.

 

If you asked the Fleischmann, Roco, etc., designers if they would prefer the gauge for 3.5mm scale RTR to be, say, 15.5mm -- they would snatch your hand off!

 

regards,

 

Martin.

[BB17005]

Specifying Scale & Gauge Is there perhaps a better way?

 

There has to be a better way of expressing scale than 4mm = 1 foot (this is a bizarre hybrid) 4mm = 304mm but 1 foot ??????????

[Guest jim s-w]

Only if you think in what you are taught and not whats right in front of you. after all 4mm to 304mm makes no sense as a scale either. Why not 1mm to 76mm? (Although as I mentioned earlier thats .2 out as a scale)

 

Nothing wrong with having a scale made up of different units. Any measuring jug does it. Miles per hour doesnt relate either does it? You buy fuel in liters but you calculate your effeciency in miles per gallon.

 

The fact that differing units are used is what makes something a SCALE.

 

Whats the difference between 4mm to 1 foot and 4mm to 0.304 meters. Both are different units of measure its just a meter relates to a mm in thousands

 

4 mm to 1 foot is easy to remember and work out and about as simplified as you are going to get, isn't that what the topic is about?

 

Cheers

 

Jim

[Miss Prism]

4 mm to 1 foot is easy to remember and work out and about as simplified as you are going to get, isn't that what the topic is about?

[bertiedog]

We are moving away from the definition of scale and gauge to other matters like the reasons for scale and commercial scale models, which is a different issue.

 

A firm disclaimer, I do not support OO or HO, just reporting the facts ........'marm.....the facts

 

But it is worth putting the record straight on HO and OO and the reasons that OO exists at all.........

 

See notes for explanations of quickie drawings. They are simplified and do not show rods etc , and in C the frames should be even closer together than I have shown. They are there to clarify a bit the text, and show the splasher issue. They are not strict scale!!!

It was not the perversity of any one modeller, model designer or manufacturer, but the perverse oddity of the UK prototypes that governed the adoption of OO in the UK, and HO in the rest of the world.

 

Lets get one thing out of the way, HO is no more or less accurate than any other scale gauge relationship, it is a good one on the relationship between the the track gauge 16.5 and 3.5 mm to the foot scale.

 

The perfect scale relationship is the real thing, one to one, and a perfect model would portray the real thing.

 

But in the real world there are problems which range from practicality, clearances, the model not representing the real thing properly due to scaling, and fittings like motors not fitting inside a scale model. All of these items and many other plagued the development of HO/00 modelling.

 

I met and discussed the subject with some of the originators of OO and it's commercial implementation, and got the real reasons carefully outlined.

First HO was developed first, by Stewart Reidpath and others in the UK, and by a group of modellers in the US at the same time in the late 1920's. The standard was basically 16.5 track and 3.5 mm to the foot.

 

What was adopted was a slightly course scale version of the real thing, the wheels had to be bigger in proportion than scale for practical reasons, (which P4 disregards for scale reasons), and cylinder centres were normal to clear UK platforms

 

By the 1930's commercial production in the States started , and there where few problems, the overall width of the outer faces of the slightly course scale wheels could be used on typical US designs which had no splashers or close fitting accessories around the wheels set.

 

Makers like Mantua, and Varney, took advantage of this to move cylinders aside a bit more than scale, and clearances for corners appeared, with the wheels sets able to move aside to go around tighter than scale curves, a vital requirement for a model in a domestic model railroad set or model. Few would have considered using strict scale curves.

 

As things developed the standards got tighter and the whole scale of HO could be used for a finer scale version, whilst retaining the ability to got around tighter curves. Most makers of brass US models after the war adopted the same approach, move cylinders apart, move frames closer than scale, and the user will not notice too much , and the model runs around reasonable curves.

 

This is the same these days in the States as it ever was, there are even tighter standards from the NMRA and Protoscale HO as well, which is basically P4 in HO terms.

 

 

NOW back to the UK, and the first commercial products, which were split between the Toy market, with Frank Hornby, and the scale market with Stewart Reidpath and Arthur Hambling. Another player had been Mr Bassett Lowke, and his engineering consultant, Henry Greenly.

 

In the late 1920's they had the same track available, 16.5mm, which was a sensible reduction from O gauge, and they had a scale 3.5 to the foot as a basis to work to, the same as the US.

 

Stewart Reidpath and fellow MRC enthusiasts for 3.5mm, and this included Arthur Hambling and Henry Greenly, started making scale models, both for themselves and for commercial production.

 

As soon as designs where drawn up and built an awful problem arose, and believe me it was, and still is incurable, that UK outline steam engines are near impossible to model in HO scale.

 

Now to most Model Railway enthusiast who are not engineers.....they cry out that this is nonsense.... the US do it, the Continentals do it, why can't we???

 

The reason is the wide spread use of splashers on Steam locos in the UK, they cover the wheels at least on the outside, and usually on the inside as well at the top. The other reason is the use of platforms on UK railways.

 

If the real thing is copied, as with P4, then all is well, thin metal can be used and the clearances and tightness can be retained, and the model with work on straight track or scale curves, and scale platforms.......and there is the reason for OO, we expect the HO/00 models to work around tight curves of say 18 inches instead of 10 feet or more.

 

So back to the 1930's and the reasons for the strange decision to move to 4mm to the foot as the answer to the troubles.

Stewart Reidpath's answer was pragmatic, to model mainly locos that did not have splashers, and move the splashers out a touch to get clearances and use wider curves generally, he suggested a minimum of about 4 foot. He also suggested that there was no problem with big electric motors, just make them smaller, and fit them in somehow.

 

The problem with motors is again the UK prototype, they are small, very small, compared to abroad, no opportunity like the US makers to fill the larger boiler with a large motor. The early Continental makers simply did not care, they were toy makers and if the motor showed who cared?

 

Henry Greenly proposed the answer would be to alter the scale, to 4mm to the foot, and put up with a narrow track than scale to allow a scale UK outline to run. His other forgotten answer was to adopt a 14.2mm gauge with HO scale, which offered the same answer.

 

However Arthur Hambling argued that 16.5mm should remain the track standard, so that the models here and abroad would at least run on the same tracks.

 

The cylinder centre distance remained the same as the scale real thing in relation to the outer face of the wheels, so that the splashers could remain in relative place, and yet the wheels could have enough side clearance to go around curves, which he proposed as a minimum of about 4 foot. Platforms could be reasonably normal as well.

 

Normal thickness side rods could be fitted, and be in the correct position in relation to the real thing, and the metal for the splashers could be of practical thickness for cast items.

 

Test models in HO and OO where built by Arthur Hambling and Stewart Reidpath, both worked fine, but the HO version was a scale model limited to a curve of 6 foot, and had very thin flanges and wheels, scale, but also with very tight tolerances.

 

The OO version sailed around under 2 foot curves and had clearances that allowed more practical making of the parts, but running on the same track.

 

The modern issue of the track sleepering looking wrong was simply disregarded as unimportant, of greater importance to them was the fact that HO/OO ran on the same track, meaning easy sales.

 

Stewart Reidpath changed his mind, and adopted 4mm, and Arthur Hambling went into major production of 4mm just before the war, and then came the final death of HO in the UK, Frank Hornby, who adopted the whole lot as a safe way of making Toy trains to an acceptable semi scale appearance.

 

OO having a narrower than scale track was not unique at the time, O gauge is undersized, are all the accepted Model Engineering scales!!!!

 

Now the argument goes that the Continental makers and the US have sorted all the issues, but as we have seen, they adopted changes to cylinder centres and have suitable prototypes in the States, or deeply distort the scale and fit to this day on the Continent.

 

We do assume the latest super detailed HO steamer for Europe is so, so very scale, but have a closer engineering look, they narrow the frames, widen splashers where fitted, (rare), fit thin rods and move cylinders out to get clearances.

 

I should add that all of this applies to steamers, Diesel never really suffered the same issues at all, but even here HO diesels often have over width bogies fitted, nobody ever seems to comment on this.

 

The drawing show the approx relationship and may help with visualisation, I was going to label them with all the tight clearances etc in HO, but frankly it is pretty obvious when you know the arguments behind the problem and realise what cures were adopted commercially, that led to OO 4mm to the foot as a product.

 

The flip side is that we have a 4mm system that can be converted to scale in P4/S4, despite the odd 4mm to the foot, and the OO models will run on tight curves with ease without having gross distortions to the body work or widened platforms than HO would need in a UK outline.

 

A strict 3.5 mm Uk loco can be built, it would simply be a P4 style model, so much smaller by the scale factor, and would be as perfectly scale in all respects.

 

But for the Model Train enthusiast 3.5mm in UK outline would be impractical if set track is needed and the platforms retained at anything near the right fit.

 

OO offered a practical solution, a commercial toy train, a semi scale model, a strict scale version etc, all based on a common scale , but not track as P4 ( and EM) adopt a scale track with it's scale restrictions,

 

Finally it should not be forgotten that the Uk market for models outnumbered the rest of the world pre war, HO was the oddity not OO, which had a larger user base in those far off days.

 

Scale Models were a UK passion, and still are, there are lots more scale modellers per population than in the rest of the world. With Toys it's the other way round, we play trains less, and although OO seems to favour toy users, it still adapts well to scale requirements for the UK prototypes.

 

I do not want to support one scale or another, we can and do live with the lot, and we get by!!!!!!!!but it needs the background to understand what happened long ago to discuss these things today.

 

Stephen.

[martin_wynne]

As soon as designs where drawn up and built an awful problem arose, and believe me it was, and still is incurable, that UK outline steam engines are near impossible to model in HO scale.

Hi Stephen,

 

Thanks for writing that. I've made the same point several times on various forums, and it is always met with incredulity.

 

regards,

 

Martin.

[bertiedog]

Martin.

Hi Stephen,

 

Thanks for writing that. I've made the same point several times on various forums, and it is always met with incredulity.

 

regards,

 

Martin.

I should again qualify myself in that of course HO models of UK prototypes can be built to "exact scale", and the impracticality applies to commercial HO operations, not a dedicated scale modeller building his own model......and to add that cylinder centres and platforms were just as strong an issue in the 1930's..

 

I have one of the original HO prototypes built, in my collection, an Atlantic GNR C1, and it's in HO scale, but altered a bit to make it go around 4 foot curves, and it has wider cylinders which do look bad, and has splashers too near the footplate edge, and was the very best effort Stewart-Reidpath and Essar could make in HO at the time (1936 approx), made even worst by the stated requirement of Henry Greenly, and others, to go around 20 inch curves, which it simply cannot do as it stands.

 

But it has duel cylinder mounts, and with the outer ones used can it go around such curves, complete with cylinders that would need the platform edges moved back half an inch!!!!!and a very, very wide rear bogie! It should have a "fixed" radial axle of course, but is a bogie with over width axle boxes due to clearances, again it can be altered to tighter scale, at the expense of large curves.

 

Hardly a scale model once altered to run on toy train track! There is just about enough side play within the splashers, but an Atlantic is better here than a Pacific, and I know a sister LNER pacific was made in HO by Essar, ( which I do not have), that simply looked awful after all the details where widened to accomplish the tight curves.

 

In comparison the OO Pacific looked better on the curves, the right look, rather than truer scale, and this helped convince Arthur Hambling that 4mm on 16.5 was better, the better, or lesser, of the two evils.

 

Stephen.

[martin_wynne]

I should again qualify myself in that of course HO models of UK prototypes can be built to "exact scale", and the impracticality applies to commercial HO operations, not a dedicated scale modeller building his own model.

Hi Stephen,

 

Yes of course. Nowadays the term H0 is normally taken to mean commercial RTR models, or kit/scratchbuilt models using the same track and wheel standards.

 

Exact-scale models in 3.5mm/ft scale are normally referred to as Proto87. See: http://www.proto87.c...is-proto87.html

 

There is no intrinsic difficulty in building UK-outline steam models in Proto87 -- apart from the difficulty of getting the parts of course, trade support is practically nil.

 

regards,

 

Martin.

[Pennine MC]

With a piece of string?

 

Oh that's easy for you experts to say, but where on earth do I get string from

[Pennine MC]

Would this stuff be any good?