Specifying Scale & Gauge

[martin_wynne]

There will of course need to be compromises, there always will be to allow what in effect is a toy, to work reliably and capture enough of the character to satisfy the market.

Agreed, but in 00 the compromises don't include the major dimensions of the bodyshell. In H0 they do.

 

(For UK-outline steam.)

 

regards,

 

Martin.

[davknigh]

PMP,

 

Sorry to be picky but the Rivarossi Royal Scot, although a fine looking model especially for its time, was done to 1:80 for the upperworks and ran on HO track. I think that falls into the "close, but no cigar" category

 

Cheers,

 

David

[bertiedog]

Only going from memory, but the Rivarossi was about as close to HO British outline as you can get from a commercial model, (but see scale issue below), but it is complete with all the problems, the cylinders are slightly undersized, moved out from the centre, the wheels are undersized, and the splashers are almost a scale foot wider than scale size. The fire box was also widened to fit the wheels width restrictions. The chassis is also thinner than scale to allow side movement of the wheels, more in proportion than an OO model.

 

It was done very carefully and does not show too much, but one of the reasons they chose the 460 was it was not practical to do a Pacific in HO as the rear bogie would have to be too wide if they used the usually minimum thickness of plastic mouldings.

The scale was also altered to 1:80 for the body, so it's also not absolutely an HO model anyway, which should be 1:87.

 

Again mention is made of fine HO makers like Roco and the like in Europe, but try running a scale rule over the width of the chassis, about 30% to 40 % thinner than scale, far further wrong than 4mm models in general. Both Roco, Lilliput, and Trix, etc., commonly widen the cylinder line to get a few extra mm for clearances, and if this was done with UK models they would clout the platforms and not fit the standard UK loading gauge.

 

For all it's apparent faults OO scale locos fit the British Loading gauge, and clear platforms correctly, and still perform on toy train set track sections. This is why Frank Hornby chose it, along with Rovex, for Toy use, as well as leaving it convertible to exact scale uses like 18mm and P4/S4.

 

Like it or loath it, we have to live with OO......too late now to change.

 

Stephen.

[Coombe Barton]

Model Railway Constructor, c.1964, had something similar to this debate.

[scaro]

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

. . .

,

 

As far as I know, TT scale in the US and Europe is the same. Both are 1:120 but in the US it's sometimes expressed as 1/10" to the foot- but this is the same proportion, and as well as the US /Europe, is used in Russia, Japan, New Zealand and probably other places.

 

TT-3, or 3mm, which comes to a rather messy 1:101.6 when expressed as a scale, is used in the UK and Ireland, and to a minor extent in the Australian state of New South Wales.

 

If you wanted to be finicky, you might possibly include 1:100 as a separate scale, which is what many people approximate for 3mm, including Wikipedia in its article on TT scale. I think a lot of the Australian TT-3 was modelled to this scale and I'm sure a lot of the UK stuff is too.

 

Ben

[Ron Solly]

Thanks Stephen & Martin, very informative.

 

Just wondering, so while it is possible to build UK models in H0 that will navigate 20" track accepting that there will be some compromises, the commercial reality is that 00 has gone too far for UK H0 to be a success? Is that the real answer?

 

 

 

As far as the OP is concerned, I think it is too late to change now ; H0, 00, P4, etc - most know what they mean - if not ,Google them.

[bertiedog]

TT is a bit of an oddity in that although the 120:1 TT scale was originated by Mr Joyce of H.P. Products in the United States in 1945/6, as the Table Top scale, it did exist well pre-war in the UK in the form of 3mm to the foot, supported by Mr Stewart Reidpath of Herne Bay in Kent, during the period that he was also supporting the use of HO scale. (3mm to the foot is 101.6:1).

 

He used the 3.5 mm HO parts like the cast brass driving wheels as they were close enough to use, and made disc wheels especially for 3mm to the foot under their ESSAR trade mark. Also plastic moulded 3mm wheel sets with moulded axles were made, an early example of injection moulding. I was told that Crystallate Plastics at Tonbridge, Kent did the mouldings for Essar. An LMS coach bogie sideframe casting was also made in 3mm scale by Hamblings at their Southampton factory in 1937/8.

 

These parts and wheels were sold again just after the war, when TT scale railways as such was introduced, again for the UK market undersized track was used, with the larger scale to suit UK outlines, but the effect was even worst than the OO compromise.

 

The trouble with 3mm to the foot according to reports of what Stewart Reidpath said, was that the motors were just to small to make!

 

Stewart Reidpath had redesigned motors for HO use, along with OO, and worked with Mantua in the US to make a tiny three pole motor, whose design was to be passed on to HP Products in the end after the war. HP also had Pittman make a small three pole open frame motor narrow enough for TT scale in 1946.

 

Arthur Hambling also made some 3mm to the foot items pre-war, wheels and printed coach sides, but they were only referred to as TT after the war, much to the annoyance of HP Products as they considered 120:1 as TT , not 101.6:1 as TT.

 

Hamblings worked with Mantua products as well in the pre-war period, supplying the Mantua fibre based 16.5 RTR track that Mantua made from 1937. But Mantua also made some 12mm fibre based track especially for Hamblings, in 1938, for use as 3mm to the foot track for the UK market. Very little must have been sold, the war stopped all progress for 3mm, but was resumed as TT by HP. The Mantua track was similar to the well known 1950's Wrenn fibre base track, and was curved in the same way, by web cutting one side of the fibre base, in both the 16,5 version and the smaller 12mm size. (Wrenn once did a TT track as well).

 

I have got a surviving Mantua Hamblings track sample though, of the Pre-war 3mm to the foot 12mm gauge track, fibre based, with US made flat bottom brass rail section. 12mm Points were handmade to order by Hamblings at the Southhampton Factory. I do not have a point as such, but I do have a factory jig that survived the enforced closure of the factory after the war. Fibre strips with rivets were used, with the brass rail soldered on to the rivets acting as chairs.

 

Stephen

[hollywoodfoundry]

As far as the OP is concerned, I think it is too late to change now ; H0, 00, P4, etc - most know what they mean - if not ,Google them.

 

And I would agree with you, as I said at the outset of this discussion.

 

Unfortunately I think many are missing an important point here, most UK modellers know what 00, HO, P4 mean, yes. But try thinking globally, outside of the UK these terms are not known so well. And equally, I doubt that many UK modellers would know some of the obscure terms used elsewhere in the world.

 

What can you tell me about F, Fn3, LS, LSn3, TTn42 ? These are scale/gauge combinations listed by the NMRA, but without knowing they are listed on the NMRA site and going there to find them, the terms tells you nothing. If I said TTn42 was also able to be specified as 120/9 you would then know it was 1/120 scale operating on 9mm track (commonly known as N gauge track).

 

If I asked what was meant by O scale, what would you tell me?

 

And before you answer, look it up on Wiki here: http://en.wikipedia.org/wiki/O_scale

 

There are several pages, mostly explaining why the term is different from country to country. My point is that many scale/gauge combinations are not able to be explained properly just by a bit of Googling.

[scaro]

 

. . .

 

These parts and wheels were sold again just after the war, when TT scale railways as such was introduced, again for the UK market undersized track was used, with the larger scale to suit UK outlines, but the effect was even worst than the OO compromise.

 

. . .

 

Stewart Reidpath had redesigned motors for HO use, along with OO, and worked with Mantua in the US to make a tiny three pole motor, whose design was to be passed on to HP Products in the end after the war. HP also had Pittman make a small three pole open frame motor narrow enough for TT scale in 1946.

 

Arthur Hambling also made some 3mm to the foot items pre-war, wheels and printed coach sides, but they were only referred to as TT after the war, much to the annoyance of HP Products as they considered 120:1 as TT , not 101.6:1 as TT.

 

. . .

 

I have got a surviving Mantua Hamblings track sample though, of the Pre-war 3mm to the foot 12mm gauge track, fibre based, with US made flat bottom brass rail section. 12mm Points were handmade to order by Hamblings at the Southhampton Factory. I do not have a point as such, but I do have a factory jig that survived the enforced closure of the factory after the war. Fibre strips with rivets were used, with the brass rail soldered on to the rivets acting as chairs.

 

Stephen

 

That's interesting, Stephen. I knew none of this.

 

Was there any direct co-operation between HP and Stewart Reidpath? Or was it all via Mantua?

 

Was it always envisaged that 3mm in the UK would be 12mm gauge?

 

I agree that the compromise is worse. I grew up in a place with 3'6" railways, and 3mm on 12mm track to me looks more like 3'6" than standard gauge. Fortunately the standard of 3mm modelling is pretty high -so you don't necessarily notice.

 

Ben

[bertiedog]

And I would agree with you, as I said at the outset of this discussion.

 

Unfortunately I think many are missing an important point here, most UK modellers know what 00, HO, P4 mean, yes. But try thinking globally, outside of the UK these terms are not known so well. And equally, I doubt that many UK modellers would know some of the obscure terms used elsewhere in the world.

 

What can you tell me about F, Fn3, LS, LSn3, TTn42 ? These are scale/gauge combinations listed by the NMRA, but without knowing they are listed on the NMRA site and going there to find them, the terms tells you nothing. If I said TTn42 was also able to be specified as 120/9 you would then know it was 1/120 scale operating on 9mm track (commonly known as N gauge track).

 

If I asked what was meant by O scale, what would you tell me?

 

And before you answer, look it up on Wiki here: http://en.wikipedia.org/wiki/O_scale

 

There are several pages, mostly explaining why the term is different from country to country. My point is that many scale/gauge combinations are not able to be explained properly just by a bit of Googling.

 

 

That's interesting, Stephen. I knew none of this.

 

Was there any direct co-operation between HP and Stewart Reidpath? Or was it all via Mantua?

 

Was it always envisaged that 3mm in the UK would be 12mm gauge?

 

I agree that the compromise is worse. I grew up in a place with 3'6" railways, and 3mm on 12mm track to me looks more like 3'6" than standard gauge. Fortunately the standard of 3mm modelling is pretty high -so you don't necessarily notice.

 

Ben

 

On a dull, wet, boring, Sunday afternoon many, many years ago I worked out with a friend in the far off days before the internet that there were at least 100 or so, scale and gauge combinations, in regular use, world wide for models, and this did not include monorails!!!

 

Re-naming them would be a lost cause, we can't even agree on Global Warming, let alone an important subject like Model Railways scales!!!

 

Research on the back of an envelope revealed the stunning information that S Scale was, and is, the most accurate representation in scale model terms of a real railway.....with P4 the best technically, but with S just beating it as no variants exist.....unless you know better!! S scale is S scale everywhere.......and a completely Imperial System as well.

 

The Stewart Reidpath/ Mantua/ HP connection was via Hamblings who were the suppliers of Mantua pre-war to the UK scale model market. S-R and Hamblings were friends and business rival and colleagues, and Hamblings bought the remains of S-R when Mr Stewart Reidpath died in the early 1950's..

 

And yes, 14.12 mm was proposed for 3mm to the foot, with the suggestion that 14.2mm might be used by a contributor to MRN as early as 1930/31.

 

Ohh......and tell the NMRA that HO is not 1:87 but 1:869757575758..........

Happy Christmas.:icon_wave:

Stephen.

[TT3]

 

What can you tell me about F, Fn3, LS, LSn3, TTn42 ? These are scale/gauge combinations listed by the NMRA, but without knowing they are listed on the NMRA site and going there to find them, the terms tells you nothing. If I said TTn42 was also able to be specified as 120/9 you would then know it was 1/120 scale operating on 9mm track (commonly known as N gauge track).

 

 

 

Totally agree with you some of those 'other' scales are quite bewildering - a chance look through a US model mag reveleaed all sorts of wacky combinations, though the obkective seems to get the gauge right and build the body around it to whatever scale is wanted compared to the UK practice of standard scale and variable rail gauges. can't image how difficult it is as a supplier to deal with this.

[hollywoodfoundry]

Totally agree with you some of those 'other' scales are quite bewildering - a chance look through a US model mag reveleaed all sorts of wacky combinations, though the obkective seems to get the gauge right and build the body around it to whatever scale is wanted compared to the UK practice of standard scale and variable rail gauges. can't image how difficult it is as a supplier to deal with this.

 

That might be a hint as to why I asked the question in the first place.

 

I know of one example of a kit model being designed recently for On30 where the original scale was 1/48 and the designer changed part way through the design process to 1/43.5 because the motor would not fit in 1/48 scale.

[Ron Solly]

........

Unfortunately I think many are missing an important point here, most UK modellers know what 00, HO, P4 mean, yes. But try thinking globally, outside of the UK these terms are not known so well. And equally, I doubt that many UK modellers would know some of the obscure terms used elsewhere in the world.

 

........

 

I would think the majority of users of model trains ( note I used the word "user" not "modeller") are happy with H0, N, 0 & 00. If they show interest in becoming a "modeller", then depending on what scale/gauge they are following, they may then resaerch all; the other various scale/gauge combinations.

 

Just in case, the words I used like "user" & "modeller" cause offence , I was trying to separate those who purchase train sets & expand using the same manuafacturer as compared to those who mix brands & hand build etc. I think the numbers of "users" would far exceed "modellers" even though we would like to think differently.

[Bernard Lamb]

And I would agree with you, as I said at the outset of this discussion.

 

Unfortunately I think many are missing an important point here, most UK modellers know what 00, HO, P4 mean, yes. But try thinking globally, outside of the UK these terms are not known so well. And equally, I doubt that many UK modellers would know some of the obscure terms used elsewhere in the world.

 

 

Quite right.

My german brother in law cannot understand why we use the same track gauge in the UK that thay use in Germany for H0 but work to a different scale. He regards it as totally illogical, empirically wrong and reckons that we are stupid.

There has recently been a spate of railway models issued in 1:35 scale. I think this comes from the military modelling people. What scale/gauge are these?

Bernard

[Steve K]

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?

I think the thing that gets some people's goat is that 4mm/ft is a mixing of imperial and metric units, which is a little illogical (even though I quite like it myself!)

 

Our Continental neighbours, naturally, pretend not to know anything at all about imperial measurements. A Polish friend at work was trying to convince me that he never uses feet, inches, miles and so on. So I asked him how big his car's wheels were...

 

Going back to the original point, it seems to me that such a system as proposed could work, but almost certainly would never happen. Just for argument's sake, I would suggest a tiny modification to the scale/gauge description - instead of the scale, use the mm/ft figure. Therefore, I would say that I am interested in 3.5/16.5. Mind you, "HO" is shorter... I don't think I need any further description to say how fine (or otherwise!) my modelling is - those figures, however, give the basics.

 

As I say, I doubt very much if such a change will happen. All the same, I'm amazed how lively this discussion has become, given that all we're arguing about is what to call our own set of compromises. You can always tell that this argument is effectively over when some says "HO for British steam is impossible", and someone else mentions the Rivarossi Scot, and then a third person mentions that it was built to 1:80, so ner, ner...

 

All in good fun, of course, but remember: it's only a model!

[F-UnitMad]

 

Research on the back of an envelope revealed the stunning information that S Scale was, and is, the most accurate representation in scale model terms of a real railway.....with P4 the best technically, but with S just beating it as no variants exist.....unless you know better!! S scale is S scale everywhere.......and a completely Imperial System as well.

 

 

I think it's actually a great pity that S Scale has never taken off for British trains (in an RTR sense). There would be none of this HO/OO debate for a start, and using a pure Imperial measuring standard just seems so 'right' for modelling trains that were built to Imperial measurements!!!

Maybe if 'OO' had been developed in the first place with a closer-to-scale gauge track such as 18mm (i.e. EM); still narrow but not perceived as so excessively narrow as 16.5mm, there wouldn't be so much hoo-haa about it, either; the same situation as exists in HO and O would also apply; just two simple choices- you either stick with the 'compromise' gauge, or go totally accurate; P87 / S7 / "P4" (or whatever 18.83 came to be known as!!) as appropriate. The fact there are so many options in 4mm scale, and that the RTR standard is so far out, is what creates such a fuss and such confusion overseas when they look at the British market.

 

I had the HO-v-OO debate with Martin Wynne back on RMweb3; keen readers of this thread will note I stayed out of the debate this time around..!!! :icon_razz: :icon_redface: :icon_lol:

[bertiedog]

It must be added the argument about whether a scale model can be made in HO does not actually apply only to HO , but all...YES...absolutely all scale ratios, it's the British Prototype causing the problem, not the model scale..

 

 

In any scale, a scale model can be built perfectly, but it will behave as per the prototype, and not go around Toy Train curves.

 

S scale, P4, proto HO, exact O scale, all work as they use scale track with all the restrictions of scale track., just the same as the real thing......

 

 

OO 4mm to the foot commercial models demand that the model goes around at least a current commercial set track curve, this prevents the use of 18.83mm track, which is the correct gauge, ........try it ..........it is totally and absolutely impossible.

 

BUT.......wait......

 

HO 3.5mm appears to do the completely impossible, because most is not of UK prototype, and the legion of compromises to get a scale HO to run on Toy Train set track can be covered up, due to no splashers etc, and no platforms, plus a galaxy of engineering tricks to get continental and US 3.5mm to go around set track corners.

 

The same tricks, chassis slimming, wider cylinders, moving splashers out, and dimensional alterations would not be put up with by a discerning UK buyer.

 

Look at the fuss around the T9, would it be acceptable to have the splashers set so far out that they would be flush?, or to slim the chassis to get the side play needed?

 

The Hornby OO T9 is vitually scale in 4mm and converts to P4, and then adopts the restrictions of scale track along with the fine wheels etc.

 

But if converted to P4 it could never run on a set track suitable for toy use, even if made to 18.83 gauge, the clearances would not allow it.

 

If the Hornby T9 was made in HO it would have to be able to function on a set track of at least 18 inches or even less.

 

This would need the wheels to move sideways for the curves, and adding the clearances, would need the frame reduced about 4mm in width, and the splashers moved out the same, resulting in splashers flush or even raised beyond the edge of the footplate, totally out of scale.

 

A typical Euro Model train makers answer to this would be to widen the whole model, It is Regularly done in HO. wider cyliders do not matter, and where they do, makers reduce the diameter below scale, as done on most German Steam loco models in HO

 

This box of tricks covers up the problem, but renders the body incapable of scale track conversion, it is no longer a scale model.

 

They would also widen the tender to match, making it out of 3.5mm scale. Such alterations are present on most so called scale HO offerings, we rarely run a strict scale rule over a Roco, Trix, or Marklin offering and most buyers in the UK are completely unaware the alterations exist.

 

The over all look is wonderful, lots of detail, seeming scale accuracy, but they are no more than super toys dressed up as scale models in many ways.

 

Anyway we can't re-invent 4mm model railways in the UK, we have a system that works, and can be scale converted.

 

*************************************************************

Happy Christmas, _get the ^{Train Set} out _and around the Tree!

:icon_wave:

[asmay2002]

Just for argument's sake, I would suggest a tiny modification to the scale/gauge description - instead of the scale, use the mm/ft figure. Therefore, I would say that I am interested in 3.5/16.5.

 

The problem with that suggestion is that not all scales are expressed as mm/ft. Gauge 1 (1:32) and S (1:64) immediately come to mind.

 

 

ASM

[Steve K]

The problem with that suggestion is that not all scales are expressed as mm/ft. Gauge 1 (1:32) and S (1:64) immediately come to mind.

On the other hand, 1:32 is exactly 3/8", or 9.525mm/ft, so it could work, especially if you call it 9.5mm, and ignore the odd 1/40th of 1mm...

 

I'm not dictating a new system, mind, just entering into this rather abstract discussion!

[scaro]

. . .

He used the 3.5 mm HO parts like the cast brass driving wheels as they were close enough to use, and made disc wheels especially for 3mm to the foot under their ESSAR trade mark. Also plastic moulded 3mm wheel sets with moulded axles were made, an early example of injection moulding. I was told that Crystallate Plastics at Tonbridge, Kent did the mouldings for Essar. An LMS coach bogie sideframe casting was also made in 3mm scale by Hamblings at their Southampton factory in 1937/8.

 

These parts and wheels were sold again just after the war, when TT scale railways as such was introduced, again for the UK market undersized track was used, with the larger scale to suit UK outlines, but the effect was even worst than the OO compromise.

 

 

 

Arthur Hambling also made some 3mm to the foot items pre-war, wheels and printed coach sides, but they were only referred to as TT after the war, much to the annoyance of HP Products as they considered 120:1 as TT , not 101.6:1 as TT.

 

. . .

 

Stephen

 

Hi Stephen

 

You say the the 3mm parts by Hamblings were sold 'just after the war' and seem to imply that TT was introduced to the UK market then. But as far as I can work out Triang did not introduce their TT3 until 1957, many years later. Did Hamblings or whoever it was who sold this stuff immediately postwar refer to it as TT ?

 

Ben

[bertiedog]

Well you've changed your tune, a year ago you were telling us how good US and Continental RTR is compared to UK RTR.

http://www.rmweb.co....art=325#p273240

 

Now you tell us they (foreign HO RTR) are toys full of compromises dressed up as scale models. Which is what OO is surely?

 

I had forgotton Rivarossi's subtefuge with the Scot, however I also recall the HO Roco Dutch Railways 0-6-0 diesel shunter derived from the Class11 IIRC. That had full outside frames years before Bachmann did with their OO 08. 4mm wide for a T9? This offering from Fleischmann seems to manage without a 4mm wide chassis

http://www.fleischma...wID=1114&page=1

 

Now clearly they've compromised it, but I said that would have to be done with UK outline when I wrote in invisible ink earlier. None of our models are 'scale' models anyway, I also said that earlier, if they were to scale, they wouldn't work.

 

No change at all, please read more carefully, for instance the T9 in HO involves 2mm clearance each side, not a 4mm wide chassis, please read it again.

 

The 2mm each side would be split to 1mm each side of the wheel, on each side of the loco to give the required estimated clearances in HO, (This cannot be measured directly from the OO version).

 

But the 2mm would ruin the splasher position, and with a T9 you cannot move the spashers out without expanding the footplate, as they are virtually flush.

 

It may sound very small, but it makes a world of difference, and the T9 is not a good case anyway, as it involves no outside cylinders, which would again scupper any effort to make it in HO which will go around set track corners.

 

On the T9, if the design was changed to have ultra thin splashers, and a half mm wrong position allowed, an HO model would be able to go around a curve of approx 28 inches, but if I put this design into production it could not be sold to the average Hornby user of set track.

 

But if the same chassis was used to make an LMS compound, the cylinder centre line is too far out of line with the wheels on maximum side movement to function at all on set track curves. I could sit down and juggle the design enough to get it to run through 28 though, just, but with difficulty.

 

I well know these points appear very esoteric, and some readers are going to miss the points or simply not be able to appreciate them, so I do try to simplify comments and then getting placed in the position of appearing to being wrong, or altering a position, which I have not.

 

The comments referred to in your quote were split between US HO and Euro HO as well, not as a generality.

 

I do know about these things as I have worked in design and manufacture of model railways for over 46 years, etched kits, wheels, track, cast kits, figures, injection moulded locos, and coach production, every aspect from drawings to prototypes and factory production.

 

There is a difference between commenting on, saying a thing is good or bad, or pointing out problems, all models have failings and plus points, but I am commenting on the model, not the user or the persons taste in what they chose to buy or use.

 

The comparison talked about before were generalities, and referred to the general over all condition of the offerings to the average user in the UK compared to the US modellers, who is better served for many reasons, ranging from the NMRA, through more enthusiast designers, and far more savy consumers than are in the UK .

 

The US modeller has had since the 1950's offered over 4500 brass HO locos on to the US market, how many are offered to the UK OO market, 10 approx?

 

It also seems to raise problems when ever the mention of the Toy train market is mentioned to UK readers, they shy away and take offence at the mere suggestion that MR is in any way related to Toy use, which of course it is.

 

Set track governs in the UK what is made, it always has, and probably always will, and HO models of UK prototypes will not go around set track curves. The design of all Tri-ang and Hornby was governed for years by the cross over arch they made, the locos had to be able to run from level track on to the ramp to the arch top, this restriction governed the design of all the Locos, and resulted in such oddiies as undersized drivers, flangeless wheels where otherwise not needed, and strange bogies like the Lord Of the Isles one.

 

Set track does not affect HO so much, as the US and even Euro prototypes are so much bigger, and they have few platforms etc., to worry about.

 

Add compromise engineering which is not commented on and they appear to pull miracles in getting the models around tight set track curves. The compromises are subtle, they would not get away with them if they were not, but the same compromises on a British outline loco would show up like a sore thumb.

[bertiedog]

(These notes only refer to the reason HO British outline is problematic.)

PMP.....

 

And on the Fleishmann Loco that you mentioned, which being a 44O is a very reasonable comparison to the T9 in most ways except for the cylinders, the splashers on the middle wheels are moved apart more than scale, an estimate from photos shows about 4mm total, about 2 mm per side. This is "hidden" by the greater width of the "footplate" the German prototype has.

 

The reason they can get this model to run on tight curves is down to the real thing, which is wider than the UK equivalent loading gauge, by about 6 mm overall, allowing the rear wheels and the middle wheels to move sideways without striking the body structure, which they would on a T9. The cab is wider than UK size, and the underside has enough clearance to allow over scale sideways movement on curves.

 

They have also reduced the thickness of the cylinders compared to photo of the real class, and reduced the bogie wheel size about 2mm under scale. The cylinder centre line is tighter than scale, to minimise moving it out, as the thinner than scale side rods help with the compromise involved. Also the rods do not in fact line up, gaining about .25mm each side, again helping with clearances.

 

All the alterations barely affect the Fleishmann model in appearance terms, they are quite minor, and obviously fully acceptable to Fleishmann users.

 

But applying the same alterations to the T9 to get an HO model would not be possible as the side of the cab is the splasher surface, and moving it out would result in an overwide loco straight away. Because OO uses an undersize wheelset width, the cab can remain scale width, and the extra movement provided by the OO standard width wheelset.

 

If the 4mm T9 is converted to full 4mm scale then it will run fine with P4 wheels as they need no sideplay of the same large amount, indeed I would set it to zero, plus a few thou for working clearances.

 

THE QUICK DRAWING SHOWS THE TIGHT CLEARANCES IN HO ON A T9(X)AND THE EXTRA ON THE GERMAN EXAMPLE(Y).

 

As I collect old models, I have several examples of HO British locos, and in general they would please the modern consumer, but they are not able to run on set track, they are scale models, and run on at least 4 foot radius curves.

 

I hope these notes explain the issue, it is far away from the Original Posters suggestions about scale naming of different scale and gauge combinations, and I feel the subject of HO and OO has been covered to exhaustion. I will post on a new posting if more precise details are needed to understand the complex issues involved.

 

Stephen.

[bertiedog]

Hi Stephen

 

You say the the 3mm parts by Hamblings were sold 'just after the war' and seem to imply that TT was introduced to the UK market then. But as far as I can work out Triang did not introduce their TT3 until 1957, many years later. Did Hamblings or whoever it was who sold this stuff immediately postwar refer to it as TT ?

 

Ben

 

As far as I know, the Essar parts and 3mm bits and pieces were referred to as "3mm to the foot, 12mm gauge" products, with the qualification that they were Table Top railway gauge, which was a copyright name of HP Products and should have been referred to the smaller 120:1 scale, so they were using the wrong name over here at the time.

 

I doubt very much indeed that many items were sold for 3mm in the UK at the time HP started up TT in the States, in approx 1945/6.

 

It would have been illegal to market any new "toys" till about 1949 anyway in the UK, and they would have had to be sold as "parts" anyway.

 

Severe restrictions stopped all new production of toys, models, and related items, unless produced with permission, or an existing brand range. This restriction closed down Hamblings Factory, then the largest scale railway maker in the world, and they continued only manufacturing in a small way and running a retail shop.

 

The UK 3mm/12mm gauge items were never listed in catalogues that I have seen, but Stewart Reidpath regularly issued catalogue supplements for his non standard items, (he made some O scale items as well as HO and OO), and I have seen one of these suggesting the use of his wheel castings for 12mm gauge. No date, but appears in paperwork matching just post war.

 

As far as I can see no Hamblings catalogue mentions TT or 3mm in the 1945/57 period.

 

It is uncertain exactly how Tri-ang got involved later on, it was a slow development, and may have started as Rovex and Stewart Reidpath worked together in the war period, both as instrument makers and model suppliers to the Armed Forces, the same as Arthur Hambling did from his Southampton factory. Stewart Reidpath were always interested in new developments in smaller scales, he even dabbled in early 2mm models.

 

The main trouble with TT at first, were the small narrow motors that it needed, and this dogged TT for many years, solved in the States by Pittman, and here by Rovex for Tri-ang.

 

Stephen.

[Grovenor]

Bertiedog wrote: Research on the back of an envelope revealed the stunning information that S Scale was, and is, the most accurate representation in scale model terms of a real railway.....with P4 the best technically, but with S just beating it as no variants exist.....unless you know better!! S scale is S scale everywhere.......and a completely Imperial System as well.

Reference to the NMRA standards and the products of Gilbert and Lionel will reveal that S gauge in the USA has been primarily a 'tinplate/hi-rail' standard compared to the fine scale of British 'S' So much so that the US equivalent of British 'S' is known as Proto 64.

 

Ohh......and tell the NMRA that HO is not 1:87 but 1:869757575758..........

 

The scale used in the US and in the UK is generally 3.5 mm to the foot which my calculator works out to

87.0857142857143 which is commonly rounded to 1:87.1 including by the NMRA, see NMRA standard scales. The results of your dubious calculation would not cut much ice. And the other Europeans are happy with 1:87, not being interested in mm:ft and probably long forgotten how they came up with such an odd scale. MOROP stds.

Cheers

Keith

[martin_wynne]

The results of your dubious calculation would not cut much ice.

Hi Keith,

 

That's a bit unfair -- 1435mm / 16.5mm = 86.97

 

which is as valid a way of arriving at the scale as any other, even if not adopted by NMRA or MOROP. At least it uses matching units.

 

In Templot I have provided both 87.09 and 87.0 to keep everyone happy. 3.5mm/ft is called S3.5, 1:87 is called P-87.

 

regards,

 

Martin.