00 and HO Scales What's the Difference?

[@stefanbattige7988]

Hello, first. please excuse my bad English! A very good explanation about 00 / H0 scale! But It would have been great to mention the width of the correct track for 00 scale models which would be about 18,5 mm. As a 00 scale modeler from Germany I don`t worry about running my rolling stock on H0 " narrow Gauge" track: first, because you can`t see a real difference , only if You look at the trains directly from the front which is seldom the case. Second, because there are still so many details as moving valve gear on steam locos, wheel details( rims to keep the wheels on track) and couplings which are not prototypical but necessary to run locos and stock safe on model track - especially the more you go down in scale from H0 to N to Z ! It gets all more and more over- dimensioned! On the other hand the advantage of 00 scale models is that You can put more detail on each model. And that the detail problems I mentioned before become less important! The point is where You put the focus! With friendly greetings from Germany

[@Trevor_Austin]

The correct gauge would be 18.83 mm. Adopting true scale track would also means going along with scale track and wheel standards. These are pretty intolerant of debris, uneven surfaces and alignment. This would result in many leaving the hobby due to frustration with poor running. Happy modelling. EDIT: Check out Scalefour Society and Pendon Museum’s website for some superb EM gauge modelling.

[@John2E0GTU-p4l]

@@Trevor_Austin By the way, EM is 18.2mm track. Proto 4 (P4) is 18.83mm.

[@SteamCrane]

From the US... This is an excellent and very clear video that answers my questions. I love the row of buildings in the background! I keep thinking of buying a 66 in HO, since I've seen them going through our US town. We live near a major mainline, and have seen both EMD and GE export units heading to US East Coast ports. We have seen 66's riding on flatcars with their trucks still attached, easily clearing the US loading gauge, and GE Powerhauls (to COLAS?). The strangest is meter gauge EMD SD70ACE's with 4 B-B trucks for VALE in South America. Those units are higher, so the 4 trucks are separate, on flatcars. Hard to believe an SD70 on meter gauge.

[@marktegrotenhuis]

As a dutch guy having bought a couple of H0 scale US diesel locomotives I can confirm: Your trains are huge when compared to European trains.

[@paullangford8179]

And in India, they do double-stack containers on flatcars, which gets more tonnage per unit train length. The pantographs on the electric locomotives are extreme.

[@SteamCrane]

​@@paullangford8179 We have entirely double stacks in the US. A good windstorm and they blow over.

[@neiloflongbeck5705]

The funny thing is, if it wasn't for Hornby we would be running on EM gauge track instead of HO gauge track. Towards the end of WW2 a group of railways modellers got together to thrash out the new standards for British Railway modelling with the intention to run trains on 18.2mm track but because Hornby had tooling for for 16.5mm track the plan for the change was vetoed.

[@BNSFfanDavid]

Thanks for posting this video- a great explanation of the differences between OO and HO scales. I've been interested in British prototypes but have never dipped my toes into modeling any of them due to concerns over the size differences.

[@thebritishrailroader]

@BNSFfanDavid glad you have found it useful. If you have any questions please feel free to get in touch

[@BNSFfanDavid]

@@thebritishrailroader , Thank you so much. I recently pre-ordered one of the Kato Class 800 sets in N scale from Rails of Sheffield, so that'll be my first foray into British modeling.

[@thebritishrailroader]

@BNSFfanDavid nice model. A bit small for my eyesight lol

[@schlehb]

Thank you very much for this well explained video! Well Done from a German Modell Enthusiast. 🎉🎉🎉

[@scottc287]

Thanks very much for this video. When I was a kid, my dad was assigned in the UK for four years. Just prior to leaving and returning to the US, I received several OO card building kits for Christmas in '77 that eventually ended up being the town on the layout I built back in the US. I knew there was a difference between OO and HO, but this is the clearest explanation I've heard.

[@thebritishrailroader]

Thanks to everyone who has responded. I know that the explanation I have given is somewhat simplified but I hope it has explained the general differences si that those outside the UK understand some of the early reasoning.

[@michaela21212]

"Double O Phobia!" I suffer with that. Great video.

[@thebritishrailroader]

@michaela21212 cheers 👍

[@Damien.D]

Hi from France, thanks for the historical info about this subject, as I always thought that H0 came before OO, and not the other way around. This scaling problem is very obvious (and sad) with locos that runs on both side of the Channel. Like, the class 66, wich is a common sight here in France. Manufacturers have to produce a wrongly sized version just for the UK market.... There were also UK steam locos that ran in France, during the world wars. And there is no way for us to realistically model such things correctly, because of scale mismatch...

[@avlisk]

1) In the early days of HO, Irv Athearn ran into a similar issue with motor size. He solved the problem by producing hood unit diesels that were to scale, except he made the hood a bit wider to accommodate the larger motor. Even when motors shrank, since he had the tooling and it was still selling, he continued to produce locos like the GP7/GP9 with the wider hoods until competition forced a change. 2) My garden railway has a similar story to your OO. It runs on 45mm gauge track, but is scaled to <a href="#" class="seekto" data-time="89">1:29</a>. It's called "A scale" (while true G scale is <a href="#" class="seekto" data-time="82">1:22</a>.5). It's "narrow gauge" because it scales out to about 4' 4" gauge, but everything else is scaled to <a href="#" class="seekto" data-time="89">1:29</a> except the bogie gauge. Garden railways also have true standard gauge, scale trains which are <a href="#" class="seekto" data-time="92">1:32</a>. But there was so much more choice in <a href="#" class="seekto" data-time="89">1:29</a> (See USA Trains and Charles Ro) that I chose to model it. The slightly too narrow gauge doesn't bother me in the garden. 3) It's always been said that in a perfect world, the 2 most popular scales would be TT <a href="#" class="seekto" data-time="72">1:12</a>0, and S <a href="#" class="seekto" data-time="66">1:6</a>4. I'm curious to see how TT fares in the coming years. I hope this was helpful and/or of interest to you and your viewers.

[@thebritishrailroader]

@avlisk thanks for the comments. I had one of those old wide bodied SDs back in the late 80s just as I was getting in to American railroads. It looked very fat lol. I am hoping TT takes off over here, I am just dipping my toes in with my first loco and a plan to build a small layout. Keep your eyes peeled for other videos 👍

[@michaela21212]

Thank you, Hornby, for lumbering us with a scale and gauge that doesn't match 😂. Time for British H0/3.5mm/<a href="#" class="seekto" data-time="68">1:8</a>7!

[@paullangford8179]

And only because they couldn't be bothered making electric motors just a bit smaller!

[@michaela21212]

@paullangford8179 No excuse for it nowadays. But so much money has been invested in bloated inaccurate models. There is no turning back!

[@1500chessie]

Highly interesting video. I´m aware of these differences for years due to 0 scale modelling , where the <a href="#" class="seekto" data-time="105">1:45</a> to <a href="#" class="seekto" data-time="103">1:43</a> is not that much difference . Had 00 scale locos in my hand and i can tell it´s a big difference to HO.

[@andrewlaverghetta715]

It definitely was interesting. I wondered how the scale was different but the gauge was the same, because I figured they were the same gauge technically. I'm glad that they're the same gauge technically, in that I can run British stuff on most HO layouts. I've got only a couple things buy it's fun to bring them out where they look mostly ok. I've recently picked up a couple of Jenny Kirk's wagons and it's interesting to put them on my HO tracks and think about how they'd look if they were in the correct scale. They already feel much smaller than a standard American boxcar. The history of it is definitely interesting.Thanks!

[@thebritishrailroader]

@@andrewlaverghetta715 thanks for the comment and glad you enjoyed the video.

[@marka87]

Totally agree on OO phobia Steve, I can’t model in 4mm for the same reason and like you do HO. It was very interesting seeing the two class 66s together, although you triggered my OCD by having them opposite ways round! 😂😂😂

[@thebritishrailroader]

@marka87 sorry about that, I didn't think about that lol. I find 00 just so jarring. This is why I may end up doing future UK modelling in TT as it is correct.

[@marka87]

@@thebritishrailroader yes I’ve been considering TT - I bought a set to try it out but decided to wait for more stock to be released before committing to it. It’s a very nice size too, just about right for uk homes.

[@mikeking2539]

Your video was perhaps the nest I have seen to show the difference between the two scales!

[@TomsRailwayStuff]

That's well explained. There used to be a Bachmann 2-8-0 Austerity in OO scale but in a version from the NS, the Dutch railway company which acquired many Austerity 2-8-0s and 2-10-0s after WW2 ended. These NS class 4300 models would mostly end up on HO scale Dutch layouts, which from a technical point was absolutely fine. The OO model would be as wide and tall as another Dutch prototype in HO scale, and would look OK. But if you would fit the funnel extension onto it like the real Austerities got here the model would be too tall and hook under bridges or the funnel extension would almost touch catenary wires, which shows the discrepancy in scale. Also for those who have seen the real Austerity against one of the other later Dutch steam locomotives in our national railway museum would have noticed that the other steam locomotives are nearly 2 foot taller.

[@CharlesTrains99]

Thank you for this video, a very good explanation of the difference between the 2 scales.

[@mrmrlee]

Thanks for the great video! As an American, I run both scales on my HO scale layout (at different running sessions of course!) The quality I like about OO is that the older era trains with the 4 wheeled cars are so much shorter than American rolling stock that I can squeeze a lot more action into my small shelf layout, without having to resort to a smaller scale such as N, which is too tiny for me.

[@thebritishrailroader]

Glad you enjoyed the video 👍

[@paulsladen]

Skip to <a href="#" class="seekto" data-time="836">13:56</a> for the side-by-side visual comparison of the <a href="#" class="seekto" data-time="68">1:8</a>7 (H0, 1ft:3.5mm) Class 66 vs. the <a href="#" class="seekto" data-time="67">1:7</a>6 (OO, 1ft:4mm) Class 66.

[@rcg3496]

Very interesting and clearly explained/demonstrated… Well done 👍🏾

[@mikedunning265]

Thanks for the video! Great explanation. I got my first model railway at 5 years old, it was HO (Marklin). In the 2000's I started switching to the OO engines and rolling stock. OO scale always felt a bit uncomfortably oversized. My compromise was to use a bit of a mix of locomotives and rollingstock from both 00 and HO, but sticking to one scale or the other in different parts of my layout in Australia. This means trying to be prototypical is just never going to work but hey, it’s a hobby I have been doing for over 50 years! I also have EU N-Scale in my home in Singapore, its simply not practical to have HO/OO in a country with homes that are so much smaller than in Australia. The other decision was to use HO buildings, and figures. The issue that you highlighted with figures was a real problem for me as I design and build most of my structures so trying to do both HO and OO was just not practical.

[@thebritishrailroader]

@mikedunning265 thanks for the comment. It is a problem. Stuff is often advertised as 00/HO but it is actually one or the other.

[@darnice1125]

Just a note, my 1960's OO scale trains had a larger flange on the wheels, so on some HO track, the flange would hit the clips holding the rails to the ties. So saying you can run OO on HO track is not always correct. HO can always run on OO track, but not always the other way around. OO rails are slightly taller. As I am strictly HO now, I'm not sure when this was corrected, if ever. You can actually see the larger flange on the OO trains you showed.

[@thebritishrailroader]

However, older HO, especially European made had very deep flanges. Modern 00 has very fine flanges, akin to RP25 (I think that's the correct standard). What I was saying is, in general, they can be run together.

[@TERRYBIGGENDEN]

A really ecellent presentation. :-)

[@kalbert2]

Thanks much for the explanation why OO scenery and buildings are a little off when I used British craftsman kits on my HO european layout.

[@stephenpike3147]

Very informative thanks. Seeing the 66 HO/OO versions side by side I will take the OO just looks so much better, am planning for older age when my eye sight diminishes! Scale ratio 87/76 =1.145 = 14.5% on length but increase in volume is that ratio cubed so up a whopping 50%. Means can add far more weight in the OO engines, so far better placed to get reasonable length trains up our not to scale gradients when engines weighted properly!

[@muir8009]

What a good, involving video. Just a couple of corrections: Bing manufactured the tischbahn, but it was entirely British in design, but more importantly, nothing to do with motors, size was just coincidental. The reason was casting tolerances and tread size, which should be fairly self explanatory. Tischbahn was too elemental as a scale per sé, but they used the half 0 track width (at the time was 33mm) but HG scaled it at 4mm but this was for modellers. Remember even in the twenties there were handcrafted exact scale models available at terrifying amounts of money (£25 for a 00 Castle when the hyper expensive Hornby 0 princess was £5) and this was the market HG aimed for. When the reformed Bing (due to that rather depressing episode where Stefan managed to escape to England and created British Trix and the ex-bing staff who were "approved" formed Trix Express) and märklin both created 00 (later what we know as H0) at roughly the same time, they used the scale of <a href="#" class="seekto" data-time="69">1:9</a>0, again, even today, continental 0 is <a href="#" class="seekto" data-time="105">1:45</a>. There was many low scale manufacturers in the UK through the thirties, both making H0 and 00, but Frank Hornby (more his sales team) went with the "modellers" scale which HG had specified as the standard all those years ago, to emphasise the fidelity and fineness of his new dublo, which they were. Also remember the dublo horseshoe motor was engineered to fit the locomotive size, again the 4mm nothing to do with the motor size, still not sure where that myth of the motor not fitting was from, neither was HG who commented on the same story back in the thirties, and if there's one person who would know, that was him!

[@thebritishrailroader]

@@muir8009 thanks for the info

[@stuartaaron613]

Very nice video. I'm in Florida (originally from New York - I was surprised to see you have a New York and Atlantic GP38-2 diesel), modeling mainly in HO and N (our club has layouts in both scales), but I also have a small roster of British OO trains as well (several of our younger members are also modeling British OO). My British models use Kadee NEM couplers. I find them less visually obtrusive than tension locks because they are smaller in size, plus I can get the wagons/carriages to couple closer together. When Hornby came out with their new TT scale line I felt that a better investment would be to produce correct British HO trains. Right now there is very little available regarding TT scale accessories, such as buildings, vehicles, and figures. Meanwhile there are enormous amounts of the same for HO scale. Plus you could run all the American and European HO trains with your new British HO trains.

[@thebritishrailroader]

It is an interesting point you raise about Hornby doing HO rather than TT. The 00 market is so strong here in the UK that it is unlikely to change wholesale as the manufacturers and modellers are too heavily invested. The TT was a pet project of the old CEO, Simon Kohler. When Hornby bought out the Rivarossi group, it got brands that already made TT, such as Arnold. We had an inaccurate (there is a theme here) version of TT back in the 60s and the new stuff is correcting it. I think it has legs and the range is steadily growing with other manufacturers entering the market. Let's watch this space!

[@MarkWick]

Thank you for this. I have been an S gauge guy for most of my model railroading years (I did work in HO for a few years), but my first layout was loaned to me, already built, while I lived in Glasgow from 1955 to 1958, and it was most likely OO. There are apparently no photos of that layout, so only my fuzzy memory provides me with any information.

[@thebritishrailroader]

@@MarkWick thanks for sharing. Glad you enjoyed the video.

[@roguico]

Very interesting well made video, explanation is very clear.

[@majormaccas]

HO and OO run on the same gauge track (same width between rails). HO models are proportionate to their wheels, OO models are a little oversized, which makes their wheels appear narrow set slightly under the slightly larger model. There saved you 18 minutes.

[@Ianshandle999]

Clear video. Worth adding that oo commercial track spacing is also too narrow, as it is the same as ho track. Uk n gauge also differs from us and European n gauge for similar reasons.

[@Trevor_Austin]

Let’s make it really simple. OO is a gauge not a scale and is really a total dog’s dinner. The nominal scale of OO is 4 mm to the foot or <a href="#" class="seekto" data-time="67">1:7</a>6.2 meaning the track gauge should be 18.83 mm. But OO uses 16.5 mm track. OO is nothing more than a historical anomaly created by Frank Hornby for convenience. 16.5 mm track was being manufactured by the mile so he merely used it and couldn’t be bothered with the non-scale appearance. Other aspect are wheel standards. Scale wheels look fabulous by comparison with the “rollers” fitted to OO rolling stock. The Scalefour Society exists for those who wish to model at true 4 mm to the foot. You will then have good looking track but with the downside that you’ll have do most things yourself - which is why we do it. Check out their website.

[@richardlee653]

On couplings, when I was young, the Triang models had tension locks and the Hornby OO ones of the time had a different type of coupling which is no longer used. One of the reasons tension locks won was that they allowed longer trains, because too much drag could cause the old Hornby couplings to uncouple unexpectedly. Personally, I am a convert to Kadees, although I am interested in other coupling systems, such as the new magnetic ones.

[@jdenm8]

Tri-ang introduced Tension-Lok because Hornby had licensed an existing design. It's still made today, the proper name is the Peco Simplex coupler. They make an improved version with magnetic uncoupling and self-centring, the Magni-Simplex, which AFAIK works with Kadee magnetic uncouplers.

[@billwilcox1060]

Well done and informative, thanks for sharing the information. FWIW, since the Class 59 is the equivalent of an EMD SD40-2 in North America, the Class 66, which has a 12-cylinder 710 engine, would be an SD59, something EMD never marketed.

[@thebritishrailroader]

@billwilcox1060 that would make sense. Thanks for the comment and glad you enjoyed the video

[@Parktonman]

I am an American Model Railroader. I have a Class 66 and a Flying Scotsmen in ho scale from Trix. Both very good models but when on my layout compared to Americans units, they look so small. Come on UK jump to ho scale. I would love to see a Black 5 and a Class 37 in ho. Among others. I did see another KZbin video of a quarry somewhere in the UK and they had a couple US EMD SW1001"s running around with some class 66's. You could tell the US equipment was so much wider and taller than the UK stuff. And this was just a small switcher.

[@thebritishrailroader]

@@Parktonman thanks for your comment and hope you enjoy the channel

[@rogerevans425]

I too had "00 phobia", especially watching trains running on code 100 rail with "steamroller" wheels. I found that they didn't look as bad when running on code 75/80 rail, and espcially if fitted with less coarse wheels, but still couldn't get my head round running on a 4ft 1.5 inch equivilent gauge track. I started to model in EM (4mm scale models running on 18.2mm gauge track - 4ft 4.5inches equivilent), but eventually settled on P4 (18.83 mm track - near enough true gauge). I thought it was going to be difficult - everyone was saying all rolling stock had to be spring or compensated. In fact most of my stock relies on the "inbuilt slop". Most locomotives can be converted from 00 easily, although some ( cough...Rapido) are difficult. Yes it does take longer to lay track than using ready to run H0/00 track, but flexible track is available, and point kits, with scale plans make it, relatively, easy. Also progrms like Templot (which I admit take a bit of learning) make non-standard trackwork much easier (and Templot can be used for 00 and H0 as well)

[@thebritishrailroader]

Thanks for sharing your experiences. I think it wasn't until I started modelling HO that the scale to gauge discrepancy in 00 became really apparent. You are right about using finer track. Even HO looks wrong on code 100

[@1337flite]

11 - the difference is 11. 1/87 to 1/76. :-) And then in scale modelling (think Airfix) HO usually means 1/72. Matchbox, when they were a thing made 1/76 kits. I have to say I didn't realise the difference was so great until you showed the two containers. I'd always thought there were "close enough", but I don't think I'd be happy mixing those scales having seen your container comparison. Thank you.

[@azuma892]

I have the Trix Flying Scotsman and the Heljan Class 66 in HO. I do try to collect British HO models whenever possible, but most of the time I just run HO and OO together. There's a similar problem in Japan where HO is 1/80 and N is 1/150, so British OO and N scale quite nicely with Japanese models.

[@davidrichie9570]

You missed an issue: wheel standards. Flange depth on common OO is deeper than common HO. Also back to back dimension of wheels is narrower on OO. This can cause derailments on turnouts.

[@LarsPW]

The couplers of OO-rolling stock would have deterred me If I knew them in 2002, the year in which I reentered the hobby. They are monsters compared to each other H0-couplers around on the continent and they lack functionality. At least after the second world war some manufacturers made their H0-locos a bit bigger than <a href="#" class="seekto" data-time="68">1:8</a>7,1 to make them look heavier and/or to get the motor packed into it. One problem had been weak stator magnets. Fleischmann H0 (Nuremberg, Germany, discontinued in 2020) developed until 1958 a ring magnet just encircling the rotor providing a continuous magnetic field and sparing any bulky steel block outside. They achieved an efficiency of 35% which was sensational then and the three pole-motor does still well if feeded by the PWM from a digital decoder. In H0 many highly prototype oriented model railroaders have had difficulties until the 1990s to get prototypical models of the UIC-standardized 26,4 m-coaches. Most models had been made significantly shorter to overcome the relatively tight curves. As far as I recall Ade and Röwa made prototypical coaches but they had been relatively small companies and provided only the most important in Germany. Fleischmann H0 kept their <a href="#" class="seekto" data-time="69">1:9</a>3,5-scale for their coaches which I like, it means a length of 282 mm instead of prototypical 303 mm. The prototypes of German double deckers (Bombardier, now Alstom) are of 27,4 m. On the continent more complex CPUs (e.g. Zimo, ECoS, Central Station, IntelliBox) and more functional types of hand controllers are in use. But nobody had an idea like Hornby to include the Bluetooth-standard in digital decoders, this is a very interesting development. They could have invented the ETCS for model railroaders if they manage to develop it further.

[@HotelPapa100]

Not being a Rail modeler, but doing the ocasional plastic model in related scales I wondered about the parallel universes of 1/87th and 1/76th (Matchbox and Airfix, mostly)

[@thebritishrailroader]

I know what you mean. As a kid I always thought it was odd that I would get soldiers from the 2 manufacturers and some were tiny and others huge.

[@mikeblatzheim2797]

I've never heard of "Bing", the manufacturer who introduced H0 would be Märklin. They also previously established 0 and 1 gauge, and later Z gauge. As a modeler of mainly German railways I'd also like to run some UK models, but as you mentioned, H0 offerings are essentially limited to rare and ancient models and the recent Flying Scotsman from Märklin/Trix. Unfortunately they didn't produce any rolling stock to go along with it...

[@thebritishrailroader]

@mikeblatzheim2797 Bing started 00 and it was indeed Marklin who introduced the true HO scale. I think they bought out the failing Bing. There are a lot of versions out there but I tries to capture it simply so people could understand why the anomaly is there.

[@paulsladen]

Bing: en.wikipedia.org/wiki/Bing_(company) - World's largest toy manufacturer (former...) Trix: en.wikipedia.org/wiki/Trix_(company) - Founded by Bing family after relocating to UK in 1930s.

[@stefanbattige7988]

Apologies, I did mean Wheel flanges instead of Wheel rims!

[@nkarsdorp8694]

In the early years of H0 scale, not all models were true <a href="#" class="seekto" data-time="68">1:8</a>7. Fleischmann started H0 as <a href="#" class="seekto" data-time="68">1:8</a>2, later <a href="#" class="seekto" data-time="68">1:8</a>5 before confirming to <a href="#" class="seekto" data-time="68">1:8</a>7. To make the models fit through tighter curves to fit a layout on a table top, longer coaches were often shortened to <a href="#" class="seekto" data-time="70">1:10</a>0 or <a href="#" class="seekto" data-time="69">1:9</a>3,5 scale. Märkin and Trix do that still for several models to this day.

[@marktegrotenhuis]

Can you run OO and H0 on the same layout? Technically yes, but the difference in scale looks off. Same with mixing exact 1/87 scale passenger cars and shortned passenger cars (length scale 1/100 or 1/93). It just doesn't look right.

[@NThomas-xj7bj]

Thanks for an interesting video, Steve. :) I've felt for some time now there's a problem with those who need so much accuracy with model railways. I've watched videos of people aging their rolling stock and thought why bother? You explained the history very well. Do you know of any groups who model the broad gauge (7 feet) steam railways of the UK? I've seen videos of North American HO enthusiasts who say that the flanges on the wheels of OO scale locos are too deep for their locally made track. They derail or can't move at all.

[@jdenm8]

It depends on when it was made. Older HO product also has tall flanges that have difficulty with more modern codes of track. The only locos I've had issues with were very old ones, I've got a Triang Class 08 shunter that won't drive through my Unitrack points, it'll instead drive up and over the plastic check rails then back down the other side because the flanges are both too tall *and* too thick to fit. It hasn't derailed though in the few times I've run it thro- over them. It's an issue that was largely fixed by the mid 1980s; the Class 08s got updated axles with shorter and thinner flanges in the mid 1970s.

[@Jettaheizer]

Very informative video! I don´t know how it´s in the UK, but the 00 scale locomotives I own don´t run on H0 scale tracks. At least on the Märklin K tracks I have. The flanges on the 00 wheels are higher than on the H0 wheels so they run on the sleepers.

[@thebritishrailroader]

The newer models run fine, but older models did have deeper flanges

[@gurdeepbedi4948]

I have HO as well as OO engine and I am running both trains on the same track without any problem

[@RobA500]

Interesting video, I was aware of the difference in size as I have some Lima Mk1 coaches in both scales and it is clear to see when they are side by side. The bit I didn't know was that I wasn't Hornby who started OO but they kept it due to the motor not fitting problem. It makes me question to why the original German manufacturer decided to make this compromise in the first place. If they knew they couldn't make models exactly half O gauge due to the motor restrictions of the time then why not use 4mm scale across the board, the models wouldn't have been any bigger than their compromised ones just the track a little wider and we would all now have a true 4mm scale. As it is It's a shame that Triang followed Hornby's OO route as by the time they started HO should have been possible in the UK and its not like the two where compatible to start with. As we all know Hornby today was Triang and not the original Hornby so we would now be HO as well and OO would have died with the end of Dublo.

[@MosriteCharlie]

4 ft 8 and a half inches is based on the Roman wagon wheels that occupied England which were spaced according to the width of a horses behind.

[@kevinshort3943]

00 is sightly taller, because Horny could not make a motor that would fit in HO. By happy coincidence it makes the model look more realistic when viewed from above (like we do 99% of the time). PS The Lima HO set I had as a kid had tension couplers.

[@sinistregoth]

Comparing 00/HO track with scalefour (18.83mm) track the difference is huge- as well as the guage being wrong, the sleeper spacing is visibly wrong and the rail height is also wrong (oddly, its too big on HO)

[@RayBoebel]

New sub here Steve! Very informative. I model US Eastcoast. However, I happen to like unusual locomotives and find British and European locomotives fascinating. Now, if I decide to pick one up, I have to make sure its HO and not OO :)

[@thebritishrailroader]

@RayBoebel thanks for the sub. Not much in HO but you can run 00 and just pretend 😉

[@chrisfrank6449]

Well explained!

[@mthury4532]

NYAR 2 61 a great engine. Was a performer in LIRR service

[@thebritishrailroader]

@@mthury4532 thanks. It is a favourite of mine

[@csxrensville5105]

Really does so the difference. You should have put them on the track. Really show how tiny the HO 66 is. 😄

[@thebritishrailroader]

@@csxrensville5105 it does indeed. Thanks for the comment 👍

[@michaelquinones-lx6ks]

As an American i see your using U.S. prototypes on your American themed layout I'm very pleased thank you, Also, TT scale was invented here in the U.S.A.

[@thebritishrailroader]

@michaelquinones-lx6ks I did read that, shame there is not any American TT rtr that I can find, I'd love that

[@michaelquinones-lx6ks]

@@thebritishrailroader Thank you very much for responding to my comments it's very much appreciated, And greetings from the U.S.A.

[@thebritishrailroader]

@michaelquinones-lx6ks no worries mate. Thank you for your comment

[@michaelquinones-lx6ks]

@@thebritishrailroader There's a Czech company that might have American prototype models in 'TT' scale i forgot the name but they do make them just google American 'TT' scale model railways Czech Republic.

[@physiocrat7143]

Applies full size too. The Hitachi stock is based on a Japanese narrow gauge type.

[@neiloflongbeck5705]

0.5mm per foot. The coupling were originally hooks similar to those still used on N Gauge.

[@marklaidlay6842]

00 models will not run on all H0 layouts. My platforms as set at H0 scale distance from track so a 4mm scale model will simply not fit.

[@robinroberts3335]

Thxs Great lnfo mate 👍🏻 👍🏻😎

[@kevinmacomber1336]

As an American, I never fully understood this and this helped. Do you have OO Structures or do you use S Scale?

[@thebritishrailroader]

@kevinmacomber1336 we have 00 structures. S scale is not a thing in the UK almost at all (I have seen 1 layout and everything was scratch built)

[@kevinmacomber1336]

@@thebritishrailroader you know, you could go into why our O is 1/48 and yours 1/43. I always wish ours was larger as that is the size much diecast is made from. I believe Lledo is 1/76 which covers OO.

[@briancooper562]

For comparison of US locomotive profiles and the European class 66/77. Look for video of the trains delivering from the factory in Canada, to the docks, trains of 66/77 locos being powered by a US loco. There is a large difference in running gauges US to Europe and UK. This is also something to watch running OO in HO scenery, OO is wider, watch platform/bridge/tunnel clearances.

[@stevem9754]

Interesting. Thanks for posting. But can I just clarify...I think you said that OO and HO can be coupled together, assuming they are both fitted with the same type of NEM coupling BUT won't the coupling of the HO model be below (14% below) that on the OO model, in which case they might not engage correctly? Or maybe the 14% difference is too small for this to be an issue?

[@thebritishrailroader]

@@stevem9754 the NEM couplers are all set at the same height as Kadee standards so no problem there

[@rjohnson1690]

I had always thought 00 vs HO was just a nomenclature thing like colour vs color. It kind of bums me out a little bit since Rapido UK has announced they are releasing an S160 class locomotive in 00. I love those WW2 US built locomotives, and was going to juxtapose one with a Kriegslok.

[@thebritishrailroader]

@rjohnson1690 it is always difficult for these types of prototypes. It often happened in the past that they would be produced by a European company in HO and we couldn't use them with 00

[@marklaidlay6842]

H0 clearly came out of 7mm scale thus originated in the UK. The history is a lot more complicated and you are perpetuating the myth that the problem was the size of the motors. It's more likely to be the width of the tyres used that caused the use of underscale gauge. Remember that splashers over wheels was a British thing and having wide tyres made such models ridiculously wide.

[@richjames2540]

Another difference is the tie spacing / sleeper spacing is different. Not interested in European models, can US and Japanese HO run on UK system?

[@thebritishrailroader]

They can indeed

[@Quince828]

Thanks for the historical and visual explanation of the differences. But can I still get away with my 00 scale British autos and buses on my HO layout? Oxford Models etc just aren’t available in true HO scale.

[@thebritishrailroader]

They do a small number of 1:87 models, all US prototypes from the 1940s to the late 60s. You could use the 00 ones but they would be significantly bigger than they should be

[@Quince828]

@ there’s a local supplier who imports British vehicles but you are right that the HO models are primarily North American prototypes. Even the Andrew Dennis double deckers which are common around here are mostly available in non Brit livery. The same is true of Rapido bus models as it is with Oxford or Lesney. So getting a nostalgic Routemaster in HO to populate the townscape is pretty much impossible.

[@thebritishrailroader]

@Quince828 I have seen them in HO I am pretty sure. Let me investigate

[@thebritishrailroader]

@Quince828 here, Braking make 1 images.app.goo.gl/N1aUJPDFUohmUKxWA

[@Quince828]

@@thebritishrailroader thanks for the info. That’s not a brand I have heard about so I will investigate further. I will have to ask my nearby dealer if he imports them, or if I buy directly will the import duties and fees be prohibitive. I’m in Canada and I’ve found that items such as WWScenics can cost more in shipping and tax than the value of the product.

[@NYCS19339]

I think there is a similar issue with N scale Japanese scale and the European and American scale of <a href="#" class="seekto" data-time="76">1:16</a>0. Are the Oxford diecast cars OO for the most part?

[@shnorth888]

Oxford British and certain European cars are OO scale but they have a line of North American vehicles out in HO

[@thebritishrailroader]

@@NYCS19339 Oxford do make HO cars for the American market, but their British range are 00

[@neiloflongbeck5705]

Japanese N Gauge is 1:150 scale.

[@IainDavies-z2l]

Another oddity is Spanish model railways, apart from the high speed lines their railways are broad guage. When I was in Granada I bought some models shown as HO, they run on OO/HO track. They are not HS models so they must me broad guage so what scale are they?

[@bahnspotterEU]

They are 1:87th scale, so H0, but they‘ve been “regauged” to run on standard H0 track. Broad gauge is something typically not modelled. Any broad gauge locos and rolling stock in 1:87 will be built to run on standard track.

[@IainDavies-z2l]

Thanks for that, they are still smaller than 4mm.

[@shnorth888]

Apparently ho scale standard gauge track, 4' - 8 1/2", works out to an unrealistic 4' 1" width in OO. Still its not that noticeable with a train on it.

[@johnmunns5964]

Well described, now can you do the story for O gauge. 1/48, 7mm, 1/43, 1/45, 1/4" and even some 1/50 🤯

[@thebritishrailroader]

That one is way above my pay grade 🤣

[@diogenes34]

Thanks very informative.

[@thebritishrailroader]

@diogenes34 glad you enjoyed it 👍

[@misterbonzoid5623]

4mm to the foot? A mixture of systems?

[@presidentxd]

Scale Guage for irish models which are 00 gauge is 21 mm.

[@CaseyJonesNumber1]

<a href="#" class="seekto" data-time="349">5:49</a> it wasn't pronounced Hornby "Doob-lo", it was Hornby "Dub-lo" (short for Double-O). Quite obvious really.

[@kkobayashi1]

And I understand N gauge is <a href="#" class="seekto" data-time="74">1:14</a>8 in the UK and <a href="#" class="seekto" data-time="76">1:16</a>0 in US and Europe? TT seems to be the only scale that has the correct track width for the scale in both Europe and UK.

[@thebritishrailroader]

Not only that, many Japanese n scale trains are 1:150! So yes, TT is one of the few true mainstream scale to gauge ratios used here in the UK

[@farmerdave7965]

Why do you have a Missouri Kansas Texas locomotive ?

[@thebritishrailroader]

@farmerdave7965 because I like the MKT from when I got into US modelling

[@evangiles4403]

The difference is the scale HO is <a href="#" class="seekto" data-time="68">1:8</a>7 and 00 is <a href="#" class="seekto" data-time="67">1:7</a>6 because if they made the english locos to <a href="#" class="seekto" data-time="68">1:8</a>7 aside from being noticeably smaller in size there would not have been enough space to fit the motors that were manufactured at the time These days the motor are smaler but the scale still had a significant followimg

[@andersgrassman6583]

British trying to talk their way out of things... However the mess is repeated in 45mm gauge, where proper standard gauge scale representation is <a href="#" class="seekto" data-time="92">1:32</a>, but British rather use <a href="#" class="seekto" data-time="90">1:30</a>,5. That is 10mm to a foot. And seriously, why on earth do you mix millimeters with imperial measurements?! Then you neither get the metric simplicity, nor the fractional beauty!? (When the first digital vernier scales came out when I was young, they were marketed as beeing able to convert measurements - but of course not! Having decimal versions of inches isn't any improvement at all. You want proper fractions, or you are better off going metric. And then there is "gauge" wire, "letter" drills and fasteners, which I have refused to try to learn. (I live in metric Sweden.) However, since the British loading gauge is so very small, using a slightly oversize scale to go with the track, isn't that bad. And because few people mix British outline models with like European, it is of little consequence. By the way, in 45mm gauge, the Americans really screwed up, using <a href="#" class="seekto" data-time="89">1:29</a>. And adding to that, the loading gauge is larger. So those models really don't mix well with <a href="#" class="seekto" data-time="92">1:32</a> models.

[@neiloflongbeck5705]

Japanese N gauge in <a href="#" class="seekto" data-time="75">1:15</a>0 scale. British N gauge track is only 0.7mm shy of being true to scale, whilst N Gauge to <a href="#" class="seekto" data-time="76">1:16</a>0 is modelling tack that in reality is 5mm over standard gauge

[@simonvancoevorden295]

We had the old Trix Twin railways in the 50s & 60s . Pretty sure they were HO scale ,even the AC ones (British outline)

[@Otacatapetl]

I've given you a like for not saying "haitch".

[@thebritishrailroader]

Thanks 🤣🤣🤣

[@GDGRailway47712]

The following video shows a UK Class 70 running in the USA with some US locomotives so you can see the size difference. Noting that the cl70 is the biggest loco to run in the UK. kzbin.info/www/bejne/Y4K4p5aJdtucZ7c Also to say that, Accurascale and Cavalex are essentially making P4 models now with OO wheelsets, you can drop in EM and P4 wheelsets easily. Hopefully someone starts on EM or P4 track some day. All model railroad / railways are compromised in some way, I don't think 16.5mm track is the biggest compromise that we make.

[@richardlee653]

You can get EM and P4 flexitrack from Marcway models. Marcway will also make pointwork to order in EM and P4. (I have some in OO gauge.) I have a feeling that Peco either does, or did, EM flexi-track, although I don't know which retailers stocked it. A few years ago they made some points in EM gauge for the EM society to sell to their members. It is a few years since I considered whether or not to get into EM, so there may be other people who have more information.

[@MySteaming]

HO is the true scale for the track. 00 Gauge was invented by the Brits because they couldn't make a motor small enough to fit in HO scale locos. So, OO Gauge Locos are slightly oversize for the track. And it's remained the case in Britain for many decades. That's what I was told many years ago as to why 00 Gauge was created.

[@little_britain]

British HO would be a nice scale - too bad there's almost no support for it. TT is pretty nice, and I may have a TT layout one of these days.

[@richardlee653]

I wish Hornby well with their TT120 project, and hope that many find it gives them the layout they want in a space they can afford, with larger stock than N gauge. However, it will be a very long time at best before a "new" (for British prototypes) scale can have a wide range.

[@__Dude_]

A little off topic: Is it traditional that English people regard themselves as non-Europeans? I mean, the isles definitely belong to the Eropean continent.

[@mikeking2539]

If they could make the smaller size motors in Europe, then why cold we not make them smaller? Or even buy them in from europe?

[@thebritishrailroader]

@@mikeking2539 I think by the time we could, we were wedded to 00 sadly

[@Jeff-fx1zy]

As couplers go, any casual observer wont know the difference.

[@mrbluesky2050]

I'm thinking the class 59's were based on the SD50 . . there an excellent comparison nose to nose photo in the class 59 book, also if you get a chance, try and catch one of the Yeoman SW1000/1 switchers against the british locomotives, 59, 60 and 66. theres the real size and gauge difference, in real life, in model form, it's almost the other way around !. and please, all train makers, do get the NEM pocket at the correct height, it's not called a STANDARD for nothing.

[@thebritishrailroader]

I agree about NEM pockets, they are a godsend. Interesting what you say about the 59s. Everything I read had them as a compressed SD40-2. I will do some further research whilst I am on holiday as you could well be right

[@clangerbasher]

On the web there are pictures of a Class 66 in America. I think this is one that was dropped when unloading. And running next to US locomotives it is looks diddly!

[@paullangford8179]

0.5 mm.

[@ServoSambo]

After watching this I’m now more doubtful as to the relevance of tt. Why not just go ho rather than create yet another standard. If tt is to scale, well, that’s got the same loading gauge issues as ho just smaller. I think the Brits are a conservative bunch that love a good tradition more than practicality. My suggestion would be to let go of oo but can’t see that happening. It’s like metric vs imperial. The Britts can’t work out what they want so they have both. Not the most practical bunch…

[@richardlee653]

If you want a continuous layout in OO (and I assume HO) that avoids "duck-unders" or lifting sections, you need a minimum baseboard width approaching 4' (120 cm). Most human arms can reach about 30" (75 cm) and still do fiddly things such as put derailed trains back on the track, otherwise you want access from at least 2 sides. I believe that it is possible to make a continuous TT layout that you can place next to a wall rather than have in the middle of a room, and still easily reach every part of it. "The Britts can’t work out what they want so they have both. Not the most practical bunch…" - Might I recommend an extra, new hobby for you? Walking can be good for you. You can take a long walk of a short pier.

[@abbush2921]

Technically 00 is narrow gauge ..

[@thebritishrailroader]

@@abbush2921 it is indeed

[@SNIPER-o5z]

It is time for you to make your models in HO scale.

[@richardlee653]

Lovely, lose all the existing ranges of British prototype OO locomotives and rolling stock, kits, buildings, figures. 😒Be better to go EM, as I understand that a fair number of recent models are relatively easy to convert.

[@John-yf8qh]

We say ‘railway’ in Britain; not ‘railroad’.