OO and HO differences

[Rick Gibson]

I’m new to railway modelling and have just begun populating my layout. Many figures are sold as OO/HO. I would assume therefore they would be a mean of 3.75mm to the foot. However, the Bachmann figures I bought completely dwarf the Preiser figures (both sold as OO/HO). It seems clear to me that 1/76 is not 1/87 so why don’t manufacturers meet in the middle? I’ve also bought some generic seagulls from Langley models. OO or HO they are HUGE. The largest U.K. gull (great black backed) is 12% smaller than the Langley models at 1/76. By HO standards they are the size of an albatross! Any thoughts? 

[JDW]

Welcome!

I think the most common answer is "because they can". A lot of people won't be too bothered that the car at the level crossing is 1/87 not 1/76, and for a long time for things like that, that was pretty much the only option. They were seen as "close enough" to not look wrong (at least, unless next to one of the right size), and if you wanted one you had little choice. Ranges have expanded a lot though over the last decade or two, meaning many things like cars are available in 1/76 too. Things like large modern warehouses are a good example of what works well in both scales, the real thing varies so much in size that an HO kit can work on an OO layout, though really the doors need enlarging a little to fit scale OO people and lorries.

I suspect too that in a lot of cases, some people simply have no frame of reference or don't care to look too closely when it comes to things that aren't train-related - look how many layouts have meticulously detailed stock but then any old car or bus. 

It's something I've always avoided wherever possible. Some things you can get away with, especially where they tend to be of variable size in real life (bins, fences, etc) and of course there's the whole argument then about not using "OO" 16.5mm gauge track (which is really HO track) and that a true OO model should use OO track.

Sometimes, the scale can be used to advantage by placing smaller items towards the back to give a greater sense of distance. 

 

[whart57]

Welcome to some of the weird and wonderful things about model railways, and some of the irritating.

 

As you say you are new, I may need to give you a bit of history about OO and HO. Both use the same gauge of track but they are otherwise different scales. Some fifty years ago however people like Triang decided that accessories and scenery items were suitable for both scales and marketed this OO/HO hybrid. But it was never a compromise scale, it was just a marketing thing. OO/HO means "not N". And "not O", and "not TT" either. As you have discovered manufacturers are a bit loosey-goosey when it comes to things away from the tracks.

 

Preiser however aren't so bad. They do a separate if limited OO range even though most of their output is in HO and N. Gaugemaster can supply, other big box outlets presumably can as well.

 

Things can be tricky if you buy figures over the internet. The Chinese internet traders use the term HO and 1:100 interchangeably (1:100 is a standard scale for architectural models as well as being almost 3mm scale) so figures can vary there too.

 

The Continental building kits makers - Faller, Kibri, Vollmer etc - are often quite nominal about scale. As a 3mm scale modeller I quite like this as their HO stuff is very often actually 1:100.

 

Most British suppliers though stick with OO, and stick to scale. Though with small things like rabbits and seagulls making them so people can actually see them in the packet can mean they are overscale.

[HSB]

There were some bus kits on sale a few years ago which were marked as 1:72 00/H0 so were apparently three different scales at the same time!!! 

[The Johnster]

The history of this goes back a century to when the scales were being worked out.  A system had been established for miniature/model railways as Gauge 1, 2, 3. and so on upwards until you were getting into narrow gauge railway territory.  18" gauge was no.3 I think, and was used for some full size narrow gauge industrial networks, including internal systems at Crewe and Horwich works.  Model railways, such as they were, were bespoke fine scale items for very wealthy clients, who had the money to spend and the room to set layouts up.  But the pressure of finding space was already becoming apparent as houses, even middle class ones, started getting smaller, and a new gauge, 0, developed.  As the 20s and 30s progressed, pioneers worked on what the market was demanding, layout that would fit on a normal size dining table; this needed to be something around half the size of 0, Half 0, H0.  As 0 had established itself at 7mm/foot, H0 was of course 3.5mm/foot and track gauge was 16mm for standard gauge.  Systems developed commercially at this scale on continental Europe and in the US, but when attempts were made to construct British prototypes to this scale, it was found that it was very difficult to fit what were considered tiny motors inside them because the British prototype itself was smaller, built to a more restricted loading gauge than Continental railways and much more restricted than US ones!

 

So, being British dammit Carruthers, we compromised.  We retained the H0 track gauge but made locos and stock to run on it at a scale of 4mm/foot.  This meant that the track was too narrow gauge at a scale 4 feet, being 8½" out for scale.  At the time most people were so amazed at the fact that such microscopic models could be made to work that nobody complained, much like T gauge these days.  By the 50s, by which time Hornby Dublo was well established and Rovex Triang were making 00 scale models, the models and many of the accessories and adjuncts to them were being described as '00/H0' with an eye to export markets, as the stock was interchangeable and buildings and accessories were reckoned to be ball park close enough for jazz for either.

 

Trix, owned by the German manufacturer Liliput, brought out a range of '00/H0' locos and stock to a compromised scale of 3.8mm/foot.

 

Nowadays we are much more picky, and our models are the better for it; so is our modelling (in most cases).  And, of course, modern manufacturers could easily make British outline models to 3.5mm/foot scale, and some say they should as they would be closer to scale.  This is true, but the trade is deeply committed to compatibility between makes, so there is a standard specification for wheel profiles, flanges, couplings, wiring, and this has developed over many years for 00 scale.  It is more correct to refer to it as a scale as the gauge is 16mm.  Attempts to introduce correct 4mm/foot scale track tend to be associated with fine scale modelling, and include EM, Eighteen Millimeter Gauge and Scalefour, which uses very fine scale standards and 18.85mm gauge track to represent 4'8½" in 4mm/foot scale.  

 

The scales expressed as ratios are 0 = 1:43, H0 = 1:87, and 00 = 1: 76.  Describing something at 1:72 as suitable for 00/H0 is pushing things a bit!  1:72 is a popular model aircraft scale.

 

Enough potted, and arguably potty, history.

 

Items like figures, buildings, trees/hedgrows, farm animals, generic fences and walls, and the like can be used in both H0 and 00 scales.  H0 figures are a little small, but quite suitable especially for pre-war layouts when real people, especially working class ones, were somewhat stunted and undernourished compared to the modern population.  3.5mm/foot scale buildings and road vehicles, road furniture, can be used in middle background locations to suggest perspective.  But the trains should ne'er the twain meet; buffers will be at different heights, and H0 scale stock will look palpable smaller up against 00 scale.

 

If you think Langley gulls are too big, try measuring the tyre width on your stock, or the thickness of plastic RTR coach sides, then compare the latter to the stuff we were being sold 30 or 40 years ago with the windows set what looked like a scale foot in from the body sides!  Where do you put the brakes?  Should they be in their correct position, which is easy as part of the bogie or axlebox moulding, which will mean they are not in line with the wheels and, if applied, would claw uselessly at fresh air until the collision, or should they be incorrectly mounted in line with the wheels, meaning you've gone to a lot of trouble to make a separate component in the wrong place.  What about splashers on steam locos, where should they go?  If you model the outside face in the correct position then the width of the splasher top has to be ridiculously out of scale to accommodate the wheel, and the wheel is too thick anyway, so let's position it further in from the edge of and get the thickness as close as we can, which will compromise the head on look of the model.  Outside cylinders mounted in the correct position need to have an inward crank in the connecting rods which is not there in reality, but if you mount them too far in it will look obvious.  Compromises, settling for second best, dammit Carruthers!

 

And don't get me started about the glaring inconsistencies in what are claimed to be a standard coupler, the tension lock...

 

But don't be put off, Rick, there's a lot of fun to be had, welcome to the hobby.  If the scale problems of 00 really get to you, the alternative is to model European or US prototype in H0 or join those poor souls in the wilderness struggling with UK outline H0.  All models are compromises to some extent, and there is little point to my mind in losing sleep over the scale compromise when our curves are much too sharp and our steam locos are electrically driven by current picked up through the track, and do not emit steam or smoke in any meaningfully realistic way.

 

Let us know how you get on and don't be reluctant to ask questions; we'll soon have you as confused as the rest of us.  One of us, one of us...

 

 

[DCB]

OO / HO is the track gauge 16.5mm.   OO scale is 4mm to the foot 1/76   HO scale is 3.5 mm to the foot 1/87.   1/72 is the old standard  Aircraft and Military modelling scale.  The standard professional modelling scale for models of proposed buildings etc is 1/100 and lots of figures seem to be made for 1/100 and sold as OO/HO

There are big variations in the height of OO/HO model people some are 24mm tall 6ft in OO others  20mm  tall 5ft in OO or 5ft 9 ish in HO.  However most are badly proportioned,  Tall and fat, short and thin.   Bachmann loco crew are awful, like a couple of 12 year old boys.  For me basically OO/HO figures fall into 2 groups, 1) Too expensive and 2) Rubbish, only Dapol seem to fall between the two. Dapol trackside are my favorites for railwaymen, several have had limbs amputated to fit my locomotives and a few guillotined to provide just the head.

For OO gauge vehicles 1/72 looks OK at the front of the layout, 1/87 at the back but only 1/76 works for vehicles on wagons, Later Airfix Tanks are 1/76 and fit OO wagons nicely whereas the old 1/72 ones just don't.

As for gulls, that's a step too far for me,  Maybe you could use a 1/160 N gauge albatross?

[Andy Reichert]

Back in the 60's, I purchased the then Airfix HO (or 00/HO )scale pack of many model people.  Being a pre-teen I curiously (but without ill intent ) laid several of the tallest ones across my track as per the unfortunate tied down maidens in the movies and discovered they would be entirely uninjured if a train passed over. Their feet just touched one rail and their heads just reached the other. I.e they were all less that 4ft 8.5" tall, even in HO scale.

 

Andy

 

 

 

 

[Jeff Smith]

Of course just to complicate things further US O scale is actually 1:48 as against the UK 1:43.5, however one quarter inch to the foot is slightly easier to work with being an all imperial scale.

 

So just like OO/HO, it is possible to mix UK and US O scale items, especially in narrow gauge.

[Nearholmer]

Johnster

 

Gauge 3 isn’t, and never was, 18”.

 

Gauge 3 was 2.5”, but is now usually cited as 63.5mm.

 

To quote the Gauge 3 Society website;

 

”Historically, some Gauge ‘3’ models of standard gauge prototypes were built to a scale of ½" to the foot. However, well known prolific locomotive designers like Henry Greenly and “LBSC” worked to the established scale of 17/32” (or 13.5mm) to the foot. The only standards that must be observed are the track gauge of 2½" or 63.5mm and the standards for wheel measurements.”

 

So, even they have minor elasticity over scale.

 

Gauge 2 = 2”

 

Gauge 1 = 1.75”

 

The history of standardised train set gauges before 1909 is more nuanced than the foregoing, but would simply add confusion in this thread.

 

Also, you’ve got the history of 00/H0 slightly inside out: 4mm/ft on 16.5mm Gauge was commercialised in the early 1920s before, not after 3.5mm/ft on 16.5mm gauge. The latter began in England as a combination, created by amateurs who were irritated by the commercial compromise, and was later adopted in the US and elsewhere for commercial use, although not before other combinations had been dabbled with.

 

Kevin

 

 

Edited May 1, 2020 by Nearholmer

[TheQ]

Of course 16.5mm is near enough 2/3 of an inch

18.83 is almost 3/4 of an inch

 

So 18.2mm  717/1000 is the EM compromise in the middle. 

[eastglosmog]

Some time ago I measured up some model cats for the very important role of Station Cat.  They were all well over a scale 4ft long (even in 00), which would have made them bigger than those giants of the cat world, Maine C00ns and Norwegian Forest Cats - neither of which breeds were common as Station Cats!

[whart57]

8 hours ago, The Johnster said:

So, being British dammit Carruthers, we compromised. 

 

 

 

Actually we didn't, which is why we have such a smorgasbrod of different scales and gauges.

 

The compromises made in the interwar years all took as their starting point the track gauge. The gauge was 16.5mm (or 5/8 inch) and a manufacturer put a body on it that sort of looked right given the compromises needed to fit in a chunky motor or clockwork spring. Even the best amateur modellers did that. The most famous layout of the late 30s and 40s is Madder Valley built by John Ahern and now preserved at Pendon. But while Ahern laid OO gauge track and built most of the lineside scenery to 4mm scale, his locos were not. He even made a Ffestiniog loco for that layout, stretching and bending it to be recognisably FR but still look right for a standard gauge branch. And capable of holding a huge motor.

 

It was finescale modellers, mainly after the war, who eschewed compromise. That's how we ended up with EM and EEM (later P4), its why there is OOO (now 2mm Finescale) that is different from N and why even in a minority scale like 3mm scale there are three different track gauges.

 

But this is a British phenomenon. In Europe and America people stuck with HO and over time demanded and got better quality representations of their locos and rolling stock. An HO loco from a European manufacturer in the 1950s might have been 1:90 scale if it was an express loco but 1:75 if it were a small shunter. Nowadays however they get slated in the model press if they deviate more than a millimeter or two from strict 1:87. The British approach was different, and was the opposite of compromise.

[Nearholmer]

Whart

 

Being picky, even your summary misses the important point that H0 was the first small scale uncompromising British scale/gauge combination. It emerged for exactly the same reasons that EM, P4 etc emerged later.

 

Spurred by the Bing/Bassett-Lowke commercial offerings in (very roughly) 4mm/ft scale on 16.5mm gauge, Young Turks like Walkely of Wimbledon MRS were building in 3.5mm/ft scale by the mid/late 1920s, and several small-batch makers provided commercial models at 3.5mm/ft thereafter. H0 had a small but steady following among British fine-scalers well into the 1930s (there was even a case made that it should be called '00' in logical succession from the existing gauges), and the argument about which was best dragged on in the pages of the MRN, not really being settled until Hornby Dublo weighed-in on the side of 4mm/ft.

 

3.5mm/ft did take off in the US, but they also dabbled in 1/8" = 1ft on 16.5mm and 4mm/ft on 19mm, which they called 00 (well before P4 emerged, and not with such fine tolerances) before settling completely; the first continental commercial offerings (Trix, which was descended from the Bing/B-L) preceded HD and wandered about a bit in scale for many years.

 

If you think about it, H0 very unlikely indeed to be of continental origin, because it hinges around a scale foot, resulting in a bizarre scale (1:87), whereas a continental scale would hinge around something rationally metric and simple to calculate like 1:100, or even 1:75.

 

So, "the very best amateur modellers" did not opt direct for fat locos; a determined proportion built to H0, and were trying to popularise H0.

 

Kevin

[Il Grifone]

The gauges 1, 2, 3 were initially set out by Märklin in the late 19th century (metric obviously and measured between the centres of the rails). British equivalents were established in the early 20th Century. Problems fitting mechanisms and overscale (very) wheels, coupled with a very loose interpretation of, scale into the limited British loading gauge led to British, Continental, and American 'models' being roughly the same size although the prototypes weren't. Following WWI and the release of the Hornby 0 gauge system which effectively killed off the larger scales*, the need was felt for a smaller size provided by Bing in Germany with their half 0 size (3.5mm to the foot (if you can talk about 'scale' with these things on 16mm (5/8") gauge.

 

Their introduction to the British market led to the comment that they were rather large for H0 which was allegedly countered by the reply (attributed to Mr. Greenly), "They are to 4mm scale" and so 00 was born. Arguments as to H0 or 00 (or even EM -  this scale formed part of the 1941 BRMSB standards).

 

Events in Germany let to the demise of Bing and the scale was relaunched by Trix in the mid thirties. Again German 'H0 models' were issued as British, so the last chance for British H0 was lost**. The advent of Hornby Dublo in 1938 was the final nail in the coffin. (Neither Playcraft in the 60s nor Lima in the 70's were successful with a resurrection.)

 

* These were never mass market products, needing lots of money to buy and lots of space to run. The most a middle class child could expect was a 2-2-0 live steam dribbler (or piddler if not in polite company). The famous 'Railway Children' toy was probably one of these.

https://en.wikipedia.org/wiki/Birmingham_Dribbler

 

I must finish here for now.  Our cat has just presented us with four kittens  

 

 

Edited May 1, 2020 by Il Grifone

[Il Grifone]

https://www.brightontoymuseum.co.uk/index/Category:Bing_Table_Railway

 

** Trix were never sure as to their scale:- German Trix stated 1:90, British Trix varied from from this to 4mm in their own literature - the 1956 (IIRC) year book quoted a mile as 60' 6" (1:87).  Late 50s Trix was 1:80 and the very last production was 4mm.  H0 remained a specialist scale.

 

Anyway BOT.

 

The term 00/H0 is much misused. It should mean something that can be used for either....

 

Preiser figures are H0 (mainly - other scales are available) but can pass in 00 if not mixed with figures in correct scale. The old Airfix set were/are a trifle undernourished, but it was the fifties. The later workmen are decidedly beefy and stand over 6' tall.

 

As regards track: almost the entire world uses Peco Streamline code 100 which was designed as an universal 'one size fits all' in the sixties (Trix steamroller wheels having finally disappeared) and with the demise of coarse Tri-ang wheels has been tightened up since. The snag is it was also designed for the American market and has H0 size sleepers at American spacing. Other makes of flexible track were available nearer to 00 scale (e.g. Formoway and Gem) but are now only available second hand.

More recently nearer scale flat bottom and bullhead track has become available from Peco. It does however require finer wheels than fitted to 20th Century products. I wouldn't say it won't run, but can't say it will either.

[Allegheny1600]

This whole subject is probably best dealt with by way of a couple of illustrations;

The sketch is self explanatory, the images show British items of rolling stock.

H0 scale is the smaller item, 00 the larger.

Images from the internet.

[Phil Parker]

3 minutes ago, Lantavian said:

Could someone explain, please, the point of EM?

 

Why go to so much effort to produce something that's closer to the correct gauge, but still isn't right?

 

The tolerances for P4 are considerably smaller than EM. You can sometimes just push the OO wheels out on a model to 18.2, but re-wheeling is the only option for the much finer P4 standards.

EM also has a very long history - when it first appeared, producing P4 components was very difficult.

[HSB]

While PECO Streamline track is sold in the US the sleepers are not to American spacing (they are also too wide). The spacing is nearer to European practice.

[Ross34]

8 minutes ago, Lantavian said:

Could someone explain, please, the point of EM?

 

Why go to so much effort to produce something that's closer to the correct gauge, but still isn't right?

5' 3" gauge in HO scale.

[Il Grifone]

6 minutes ago, Lantavian said:

Could someone explain, please, the point of EM?

 

Why go to so much effort to produce something that's closer to the correct gauge, but still isn't right?

 

It's simple. The problem with 00 is the narrow gauge. One can either ignore it, or change the scale or  gauge. Scratch building literally everything is the only way ahead changing the scale, whereas EM allows the use of 4mm R-T-R or kits just changing the wheels and laying the track to a wider gauge.

[Ross34]

When I switched from OO to HO I envisaged being able to utilise alot of my 4mm bits n bobs...I was surprised how much I actually couldn't..and being equally surprised how half a mm made such a difference.

But if nothing else, I could buy scale track off the shelf. ...till I started looking at P87!!

Edited May 1, 2020 by Ross34
Spelling

[Il Grifone]

10 minutes ago, HSB said:

While PECO Streamline track is sold in the US the sleepers are not to American spacing (they are also too wide). The spacing is nearer to European practice.

 

We are talking early sixties. It was probably a compromise between Continental and American. The Streamline spacing is two feet in H0. it's taken fifty years for Europe to catch up. In 00 it's 1' 9" - far too close.

 

I work on the basis that an error of 3% in a model is probably not noticeable as long as it's spread out along the model. It's about 0.1mm in 3.5mm/foot.

Edited May 1, 2020 by Il Grifone

[whart57]

3 hours ago, Nearholmer said:

If you think about it, H0 very unlikely indeed to be of continental origin, because it hinges around a scale foot, resulting in a bizarre scale (1:87), whereas a continental scale would hinge around something rationally metric and simple to calculate like 1:100, or even 1:75.

 

So, "the very best amateur modellers" did not opt direct for fat locos; a determined proportion built to H0, and were trying to popularise H0.

 

Kevin

 

I don't think I ever suggested HO originated in Europe, only that Europe settled on it as a complete thing and not one of many interpretations.

 

Scale ratios are hardly ever rational, I mean who would choose a scale of 7mm to the foot. Some scales are sort of rational - 1:24, 1:32, 1:48 for example are making use of the way we have 12" in a foot and we subdivide inches on a ruler by halving a gap multiple times to get 1/16 or 1/32 of an inch as the smallest division. And let's not get started on that metric/Imperial mix of 4mm to the foot, 3mm to the foot etc

 

In the early days people started with a gauge and worked out the scale ratio from that. So you had Gauge 1 was 1 3/4 inch, Gauge 2 was 2" and Gauge 3 was 2 1/2". When they started to go smaller Gauge O was 1 1/4 inch and then OO was 5/8", half of O.

 

For scales Gauge 1 quickly settled down to be 1:32 scale, and it still is in Europe. Why British Gauge 1 modellers adopted a weird 10mm to the foot hybrid ratio is a mystery to me when 3/8" to the foot (and 1/32" to an inch) is so much more logical. Gauges 2 and 3 had weird ratios, 17/32" to the foot sticks in my mind as the original Gauge 3 scale ratio. As an aside, how many realise that modern G scale is in fact Gauge 3 narrow gauge? In those early pre WW1 days though someone like Bing might well produce the same model for Gauges 1 and 2, the only difference being the wheelsets

 

It's all a fascinating study into manufacturing compromises, but probably not for here.

Otherwise though we get what we

[Andy Reichert]

1 hour ago, Ross34 said:

When I switched from OO to HO I envisaged being able to utilise alot of my 4mm bits n bobs...I was surprised how much I actually couldn't..and being equally surprised how half a mm made such a difference.

But if nothing else, I could buy scale track off the shelf. ...till I started looking at P87!!

 

 

Yes, but most HO track is easily converted to 16.5 mm gauge Proto-87. Changing the gauge is a massive amount of work and skill by comparison. And you can convert UK 00 RTR vehicles stock to P87 by  just changing the wheels

 

For UK modellers in particular, A slightly wider flange way version of P87 is 00 P. This uses the P4 flange way on 16.5 mm gauge and so allows the use of the existing wide range of UK P4 wheels for steam locos. The crossing in the pictures above is actually the 00P version, but it's appearance is almost identical to to true P87.

 

Andy

 

 

 

Edited May 1, 2020 by Andy Reichert
Adding 00P info

[Mick Bonwick]

21 hours ago, Rick Gibson said:

 Any thoughts? 

 

Just look at what you've started!