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We are back to the 'check gauge' . To run through a crossing a wheelset has to run through the flange gaps on both sides of the crossing and therefore has to be greater than the check span (the distance over the outer edges of the check/wing rails) and less than the check gauge (the distance between the outer edge of the check rail and the crossing nose.

There was an instructive film about this on the NMRA website, but I have not been able to find it again.

NMRA S4.2 (standard wheels H0 scale) states  https://www.nmra.org/index-nmra-standards-and-recommended-practices

check gauge          (K) 15.32  +0.05 - 0.18mm

Back to Back         (B) 14.55 +0.05 - 0.18mm

Flange thickness  (T) max 0.76mm

The original imperial measurements are quoted to a thou. (and good luck!)

 

I suspect the Gibson reduction from 14.8 to 14.7 was because 14.8 is excessive. (IMHO) IIRC the flange thickness of Gibson wheels is 0.4mm, which would suggest an increase to 14.7 rather than 14.8. It should run, but we return toreasom EM gauge is 19.2mm.

 

My  reference to 'average' as I said was taken from the Railway Modeller and nothing to do with 2.4 children (it's 1.7 now apparently) https://www.onaverage.co.uk/other-averages/average-number-of-children

 

In the sixties, the old Trix Twin and early Tri-ang wheels were obsolete and the extremes were represented by BRMSB on one hand and Tri-ang on the other, Dublo being somewhere in the middle. Peco (and Gem and Formoway) track were designed for this and will accept them all without great problems. (Those remaining are mainly due to varying flange depth and filled in flangeways causing wheel drop/bounce). The adoption of Dublo standards by Tri-ang* in the late sixties/early seventies paved the way for tightened tolerances later on.

 

* They are always Tri-ang to me whether they call themselves Tri-ang Hornby or Hornby!

 

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2 hours ago, Il Grifone said:

 

 

I suspect the Gibson reduction from 14.8 to 14.7 was because 14.8 is excessive. (IMHO) IIRC the flange thickness of Gibson wheels is 0.4mm, which would suggest an increase to 14.7 rather than 14.8. It should run, but we return to reason EM gauge is 19.2mm.

 

My  reference to 'average' as I said was taken from the Railway Modeller and nothing to do with 2.4 children (it's 1.7 now apparently) https://www.onaverage.co.uk/other-averages/average-number-of-children

 

In the sixties, the old Trix Twin and early Tri-ang wheels were obsolete and the extremes were represented by BRMSB on one hand and Tri-ang on the other, Dublo being somewhere in the middle. Peco (and Gem and Formoway) track were designed for this and will accept them all without great problems. (Those remaining are mainly due to varying flange depth and filled in flangeways causing wheel drop/bounce). The adoption of Dublo standards by Tri-ang* in the late sixties/early seventies paved the way for tightened tolerances later on.

 

* They are always Tri-ang to me whether they call themselves Tri-ang Hornby or Hornby!

[added emphasis]

 

While much of your post I would agree with, other parts I have to challenge , sorry.

 

- Triang's wheel standard in the 1960s was very coarse, and their back to back was  then 13.5mm . I'm not absolutely certain when they moved to something finer, but it seems to have been around 1972-4, when they changed to 13.8mm back to back and the Silver Seal plastic wheels. (Probably more or less at the point at the point when they became Hornby Railways not Triang-Hornby)

 

Triang Transcontinental and other "genuine Triang" stock will not run on Peco Streamline, and has not done at any time in the last 40 years.

 

Around 1990-2000, Peco Setrack was definitely coarser than Streamline : I presume this was to accommodate vintage Triang with the 13.5mm B2B. Streamline would obviously take the 13.8mm Hornby of the 70's , 80s and 90s. (Whether Setrack is still this coarse I don't know). 

 

It's possible that Peco introduced the 13.8mm standard for Streamline with the Code 75 range in the 70s, and only later moved Code 100 up to the finer standard on the quiet

 

(This history, I suspect , is why I had trouble with Hornby set points on my late 1970s teenage ;layout. I suspect the System 6 Hornby points were designed to fit the older Triang wheels with 13.5mm B2B, and of course my Wrenn, Airfix and Lima diesels weren't happy....)

 

- Hornby Dublo as you indicate , used a 14.1mm or 14.2mm Back to Back . So did Airfix,  but 20th century Hornby Railways never did. Hornby moved from 13.8mm to 14.5mm around 2000 (although one or two models during the transition appeared with 14.1mm.

 

Hornby Dublo flanges were too deep for code 75. Hornby Railways flanges were fine with it - so were most (but not early) Lima flanges

 

- I don't know why it would be necessary to move from 14.8mm to 14.7mm: if the EM B2B is 16.5mm and the track gauge is 18.2mm, then the equivalent Gibson OO wheel should have a B2B of (16.5-1.7) mm = 14.8mm. The OO Fine standards are simply 1979 EMGS standards cut down by 1.7mm

 

Given the number of people who want to get back into the hobby using some 1970s-80s Hornby stuff they found in the loft - if not something even older - it's worth going over what Hornby and others were actually doing in the last quarter of the 20th century, as there are some practical implications.

 

I have had to ease the back to back on Hornby 5 pole ringfields to get them to run through my Marcway points - they were certainly not 14.2mm B2B. And the older issues of the Pacer certainly had coarse wheels to 13.8mm back to back and need rewheeling to run

 

Could you run 1980s Hornby on the new Peco bullhead track ?? Someone will doubtless try it, but I suspect the wheels may jam, and the flanges might well catch the chairs as well. Lima will run, yes - but flange strike is likely to be an issue

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Peco tightened up the flangeway on Streamline points sometime in the last 30 years.

 

I have been building a new fiddleyard using small radius insulfrog code 100 points bought in the early 90s at the latest and ran out so had to buy some new ones (same type) to finish off. The flangeways are noticeably narrower on the new ones which struck home when I tried to run a Triang Hornby Murgatroyds tank through them and they jammed, whilst running happily through the old ones.

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1 hour ago, giz said:

Peco tightened up the flangeway on Streamline points sometime in the last 30 years.

 

I have been building a new fiddleyard using small radius insulfrog code 100 points bought in the early 90s at the latest and ran out so had to buy some new ones (same type) to finish off. The flangeways are noticeably narrower on the new ones which struck home when I tried to run a Triang Hornby Murgatroyds tank through them and they jammed, whilst running happily through the old ones.

 

Thanks for this. Useful info.

 

Might be worth checking the back to back on that Murgatroyds tanker . 13.5mm or 13.8mm? (It's possible Peco may have tightened up the flangeways on code 100 Streamline twice - once in the 1990s and again recently...)

 

I remember someone producing a late Triang Transcontinental diesel and us seeing if it would run on the club's then US HO layout , laid with Code 75 Streamline. It jammed . This would be the very late 90s - so code 75 was already to the finer dimensions then (Obviously the track on the layout had been bought some years before the incident...)

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6 hours ago, Ravenser said:

Brightspark has done some research, and fallen down one of the more curious twists of 4mm history. 

 

The 1936 "recommendations" have nothing to do with the BRMSB as people historically knew it . In 1936 the Model Railway Constructor was a one-man band , and the man was E.F Carter. At one point he was even personally binding the magazines as well as posting them out to subscribers. 

 

Actually I am very much aware that MRC (Model Railway Constructor - a magazine,[for the benefit of our younger readers) and the BRMSB was a one man band. Or at least a small cartel of enthusiasts who should be praised for their determination in getting some kind of standardisation of OO.

 

I have a very incomplete collection of magazines from that period so thanks for pointing out the issue that I was hunting for.

 

On 21/08/2020 at 08:39, Il Grifone said:

19mm became 18 (EM) for clearance reasons - it remained 19mm in the states as their larger loading gauge and central rather than lateral framing of rolling stock favours a wider gauge. EM became 18.2mm later, as it was found that there was insufficient tolerance (play, slop) for reliable running.

 

I am not so sure that 19mm became EM Gauge as somewhere (probably another magazine I can't find or don't have) they were listed side by side and as said else where 19mm is known as American 00.

 

I don't know about Peter Denny, but Metropolitain junction was much closer to 18mm. I think that there is some confusion about gauge widening (on curves) which for EM (18mm) goes to out to 18.2.

The 18.2mm gauge track standard (for straight track) seems to have appeared after Ratio introduced their track bases, which were set at 18.2. There seems to have been some revision of EM track standards at that point (late 70's and early 80's) before settling down the current set of standards. 

 

O f course this is the kind of confusion you get when you make compromises. The ONLY way forward is model S4, where there are no compromises. :D

 

Finally I just want to say that this is a very enjoyable and informative thread. Working to the other 'compromised' track standard, I was not aware of the recent changes to 16.5mm. 

And no I am not going back...its still too narrow, unless you model Glasgow tram.

 

 

 

 

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29 minutes ago, Ravenser said:

 

Thanks for this. Useful info.

 

Might be worth checking the back to back on that Murgatroyds tanker . 13.5mm or 13.8mm? (It's possible Peco may have tightened up the flangeways on code 100 Streamline twice - once in the 1990s and again recently...)

 

I remember someone producing a late Triang Transcontinental diesel and us seeing if it would run on the club's then US HO layout , laid with Code 75 Streamline. It jammed . This would be the very late 90s - so code 75 was already to the finer dimensions then (Obviously the track on the layout had been bought some years before the incident...)

They are 13.8mm B to B (or thereabouts). Plastic wheels on metal pin point axles.

 

The flangeways on the new code 100 points look to be the same as those on the code 75 FB points used on the scenic part of the layout.

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1 minute ago, brightspark said:

 

Actually I am very much aware that MRC (Model Railway Constructor - a magazine,[for the benefit of our younger readers) and the BRMSB was a one man band. Or at least a small cartel of enthusiasts who should be praised for their determination in getting some kind of standardisation of OO.

 

I have a very incomplete collection of magazines from that period so thanks for pointing out the issue that I was hunting for.

 

 

I am not so sure that 19mm became EM Gauge as somewhere (probably another magazine I can't find or don't have) they were listed side by side and as said else where 19mm is known as American 00.

 

I don't know about Peter Denny, but Metropolitain junction was much closer to 18mm. I think that there is some confusion about gauge widening (on curves) which for EM (18mm) goes to out to 18.2.

The 18.2mm gauge track standard (for straight track) seems to have appeared after Ratio introduced their track bases, which were set at 18.2. There seems to have been some revision of EM track standards at that point (late 70's and early 80's) before settling down the current set of standards. 

 

O f course this is the kind of confusion you get when you make compromises. The ONLY way forward is model S4, where there are no compromises. :D

 

Finally I just want to say that this is a very enjoyable and informative thread. Working to the other 'compromised' track standard, I was not aware of the recent changes to 16.5mm. 

And no I am not going back...its still too narrow, unless you model Glasgow tram.

 

 

 

 

 

My understanding - from the wartime MR Constructor - is that 18mm was a pet idea of one well-heeled London area modeller , as a "workable compromise" amongst the competing pre-war claims of HO, OO and 19mm gauge. Just to add to possible confusion he was also a member of The MRC in London : several early photos of Buckingham GC in Peter Denny's books, taken in the late 1940s when he was living in London are credited to F.W Chubb.... 

 

As the gentleman in question bought out EF Carter c1938 and became proprietor of the Constructor , when the wartime BRMSB was launched in response to a letter to the Constructor, he was rapidly co-opted to the cabal and able to push his "compromise gauge" of 18.0mm . (It looks like the Constructor camp "recycled" the title of BRMSB from Carter's earlier piece when the little "standards committee" needed an official title)

 

It seems that at first the BRMSB were going to publish only standards for 18mm gauge /4mm scale and 16.5mm gauge/3.5mm scale - ie HO and EM standards only - and decline to get involved with OO as we know it at all . There seems to have been such a backlash against that idea that they were forced to produce a OO standard after all, but they kept trying to re- define OO as 18mm gauge: the standards were originally published as "Scale OO" (18.0mm = EM) and "Nominal OO" (16.5mm = OO)

 

It's worth at least trying to document the origins of EM. You might well be right about Metropolitan Junction being to 18.0mm gauge. I think Peter Denny wrote that the 18.2mm on Buckingham originated from his home made curve tool - a piece of  square timber with cuts sawn into it so it could be flexed into a curve

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I thought I would actually measure some items, but can't find a decent vernier. All I have at the moment is one of those plastic things, so the last figure is somewhat dubious. When I find the decent one....

 

As they came to hand. (dimensions in millimetres):

Tri-ang 'Polly' 0-4-0 B2B 13.8/9 (i.e. one axle 13.8 and the other 13.9)   Flange thickness/depth 0.8/1

The usual question of where to measure the latter is irrelevant as the wheel profile is uncompromisingly square!

A 1mm flange depth rules out any running on code 75!

Tri-ang 'Blue Pullman' power bogie 13.7  0.8/1 (the same bogie as the DMU from the fifties).

Tri-ang 'Jinty' 0-6-0T (solid wheels 13.9  0.7/1.5

Tri-ang 'Hall' tender 13.8  0.7/1

Hornby 'Jinty' 0-6-0T (new chassis 1978) 14.2  0.5/1

Wrenn 'Castle' tender 13.8/14.2  0.5/1

The flange depth is very dubious, but Tri-ang wheels bump on the flangeways of Dublo points.

These figures show 1. a lack of quality control! and 2. Hornby using finer wheels from the late seventies.

 

Code 75 track should have finer standards otherwise it's pointless (no pun intended) using the finer rail.

 

Dublo track is code 125* (3 rail) and 110 (2 rail), Tri-ang code 150 or thereabouts and Hornby is code 100 of course.

*Fine scale in 1938!

Edited by Il Grifone
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11 minutes ago, giz said:

They are 13.8mm B to B (or thereabouts). Plastic wheels on metal pin point axles.

 

The flangeways on the new code 100 points look to be the same as those on the code 75 FB points used on the scenic part of the layout.

 

Then Peco have tightened up Streamline Code 100 in the last 5 years, and it's probably now to BRMSB OO (1.25mm flangeway) . That should be compatible with all Bachmann, Replica, Lima, Airfix and Mainline, as well as post 2000 Hornby

 

I think this fact had better be shouted pretty loudly from this thread, because there is a lot of pre 2000  Hornby kicking around, and a lot of people are now going to have exactly the same experience as you have just had.

 

There are 2 workarounds

 

- a) fit new Hornby or Bachmann wheels to the tank wagon - should be easy if they are on pinpoint axles

- b] use Setrack points (nasty sharp things!) if you must run vintage wheels. That will mainly be an issue with 20th century Hornby locos...

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11 minutes ago, Il Grifone said:

 

Code 75 track should have finer standards otherwise it's pointless (no pun intended) using the finer rail.

 

 

That , I suspect, is why code 75 has never really displaced code 100. People wouldn't buy it, because they assumed it was too fine - but Peco made it just the same as code 100 so there was no real advantage . Then they wouldn't breathe a whisper of the dimensions for fear of frightening the horses.

 

Result was they got the worst of all worlds commercially.....

 

P.S - the Jinty was retooled in 1978 but it's been in production more or less ever since and may still be in the Railroad range. 14.2mm sounds like your example may be post 2000 Chinese production...

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Reading the posts that appeared while I was writing the above, made me recheck the late ' Jinty'. Her wheels are pushed tight against the wider part of the axles so the 14.2mm is as intended by her manufacturer.

 

Peco have never to my knowledge admitted to any change in their Streamline track dimensions or even stated what they are beyond code 100....

 

A Tri-ang Murgatroyd's tanker with either have The old Tri-ang wheels if it has the open axleboxes or the plastic wheels on steel axles if a later one. For the first type replace the whole bogie (I use Ratio, but Cambrian do them as well I believe). This is also advisable with the plastic efforts to correct the wagon ride height*, but pinpoint wheelsets  can be used.

* There's little point in worrying about the rail height if the buffers sit 2mm too high (or is this just me?).

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5 minutes ago, Ravenser said:

 

Then Peco have tightened up Streamline Code 100 in the last 5 years, and it's probably now to BRMSB OO (1.25mm flangeway) . That should be compatible with all Bachmann, Replica, Lima, Airfix and Mainline, as well as post 2000 Hornby

 

I think this fact had better be shouted pretty loudly from this thread, because there is a lot of pre 2000  Hornby kicking around, and a lot of people are now going to have exactly the same experience as you have just had.

 

There are 2 workarounds

 

- a) fit new Hornby or Bachmann wheels to the tank wagon - should be easy if they are on pinpoint axles

- b] use Setrack points (nasty sharp things!) if you must run vintage wheels. That will mainly be an issue with 20th century Hornby locos...

I've already swapped them with some Jacksons I had in stock (small dia, 10.5mm?).

 

Comparing the new Peco code 100 points with the equivalent code 75, they appear identical apart from the depth of rail. Estimating with a piece of 40 thou plasticard, I would say 1.25mm flangeway is about right. The old ones look to be at least 1.5mm.

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3 minutes ago, giz said:

I've already swapped them with some Jacksons I had in stock (small dia, 10.5mm?).

 

Comparing the new Peco code 100 points with the equivalent code 75, they appear identical apart from the depth of rail. Estimating with a piece of 40 thou plasticard, I would say 1.25mm flangeway is about right. The old ones look to be at least 1.5mm.

 

Streamline used to be 1.39mm flangeway and Setrack used to be 1.55mm . That caused mayhem on Ravenser Mk1 when I rewheeled a Lima 20 with Ultrascales

 

Sounds like your old Streamline was to a very old "1980s and earlier" standard of 1.55mm and the new ones have gone through 2 rounds of tightening up.

 

Thanks for the info

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6 minutes ago, Ravenser said:

 

Streamline used to be 1.39mm flangeway and Setrack used to be 1.55mm . That caused mayhem on Ravenser Mk1 when I rewheeled a Lima 20 with Ultrascales

 

Sounds like your old Streamline was to a very old "1980s and earlier" standard of 1.55mm and the new ones have gone through 2 rounds of tightening up.

 

Thanks for the info

They could date back to the 80s, early 90s was when I last bought any code 100.

 

Just tried a Hornby 25 that I bought in the late 70s and have never knowingly adjusted the b to b and it runs through the new streamline points. Checked the b to b and its 14.1mm. Did Hornby increase their b to b in the late 70s? Will see if I have any 80s Hornby and check it.

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See my post above re Hornby 80s wheels.

 

I just checked my Class 25 and Class 35. All 8 wheelsets are 14.2mm B2B.

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10 hours ago, giz said:

Peco tightened up the flangeway on Streamline points sometime in the last 30 years.

 

I have been building a new fiddleyard using small radius insulfrog code 100 points bought in the early 90s at the latest and ran out so had to buy some new ones (same type) to finish off. The flangeways are noticeably narrower on the new ones which struck home when I tried to run a Triang Hornby Murgatroyds tank through them and they jammed, whilst running happily through the old ones.

I think you'll find that Peco Streamline points (not counting Set Track as that is a different beast), have evolved far more frequently than that.

For instance, there was a news item early in 1973 & the point springs were going to be mounted on top.

I suspect the points need retooling every few years (10?) and little changes get made and are undocumented each time. 2 things to observe there, firstly it's going to take sometime to go through the range of points - several years, then start again?

The other thing, is that Peco are unlikely to advertise most of the changes, because they want to move on the older stock.

 

I believe the Electrofrog version of the points became available, shortly after they moved to the new location. Yes, nothing to do with flangeways, but thought I'd throw that into the discussion!

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Bit of irony is that the old 1950s Triang Jinty etc with Mazak weels and the shorty coaches with two piece wheels can be made code 75 compatible by pushing the bogie axles out and turning down the flanges on the wheel halves by spinning the wheels in a power drill chuck and holding against a fie or sandpaper,  when the flange is shallow enough add spacers between the wheel halves to reset the gauge when reassembling.  The Jinty can either have Markits wheels or the maxzak can be filed down and one wheel at a time removed so spacers can be slipped on the axles to get the B to B right and stop excess side play, One wheel at a time makes getting the quartering right much easier. The later plastic wheels on pinpoint steel axles might just get through code 75, they are fine on code 100, but the one piece sort of 1985-90 ones are are hopeless.  The solid iron and steel tyre driving wheels are pretty hopeless but the Hall/B12 takes modern Castle/ County tyres if you want to save a few quid vis a vis Markits. But there is no reason you can't run 50s Triang on code 75 with a bit of bodgery. Now why anyone would want to is another issue altogether.

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14 hours ago, Ravenser said:

 

omis

 

P.S - the Jinty was retooled in 1978 but it's been in production more or less ever since and may still be in the Railroad range. 14.2mm sounds like your example may be post 2000 Chinese production...

 

It was a completely new model (AFAIK only the coupling rods* and motor are the same and the latter had a new gear ratio). The one I measured  (I have several examples of this chassis) is definitely one of these. The later Chinese version has the 'floppy' SSPP chassis with the cr*ppy motor** and traction tyres on the centre axle. It works OK if the rear axle springs are set up properly, but can give problems. (A product (especially intended as a toy) where the instructions suggest cutting bits off springs leaves something to be desired IMHO.)

 

* They could have corrected the wheelbase while they were at it.  This error persists from the original Tri-ang 3F 0-6-0T of c.1954.

** X.04s will long outlive these things....

 

We seem to have drifted (that's RMweb for you) rather from the original question as to the best B2B for Peco code 75 track. The 'correct' BRMSB setting for 16.5mm track  is 14.5mm* (assuming BRMSB 0.5mm Flanges) which is a bit sloppy and allows 1mm of play between a wheelset and the rails. In my early days experimenting with scale (as opposed to the ship anchor chain type prevalent back then) 3 link couplings, I found this was sufficient to allow buffer locking. The tighter clearance of EM seemed the way forward and a sample of the then new SMP track convinced me. (No thoughts of DOGA or 16.2mm gauge around 1970! It would have involved home made track anyway, so why not go the whole hog and do the job properly?)

For the Peco track it will depend on the flangeway dimension.  1mm flangeways will need the wheels moved out from 14.5mm B2B

 

Unlike the NMRA, which is precise on these matters (to 1/1000"), no tolerances are quoted. Somewhere I got the idea of "half the last figure i.e. 0.05mm)". Not unreasonable, but Wikipedia seems to disagree.

 

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

 

When no other tolerances are provided, the machining industry uses the following standard tolerances:[3][4]

1 decimal place(.x):±0.2"

2 decimal places(.0x):±0.01"

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I found this (looking for something else of course!).

 

 

and this less relevant but... (The music is irritating - mute the audio!)

 

 

Edited by Il Grifone
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7 hours ago, kevinlms said:

I think you'll find that Peco Streamline points (not counting Set Track as that is a different beast), have evolved far more frequently than that.

For instance, there was a news item early in 1973 & the point springs were going to be mounted on top.

I suspect the points need retooling every few years (10?) and little changes get made and are undocumented each time. 2 things to observe there, firstly it's going to take sometime to go through the range of points - several years, then start again?

The other thing, is that Peco are unlikely to advertise most of the changes, because they want to move on the older stock.

 

I believe the Electrofrog version of the points became available, shortly after they moved to the new location. Yes, nothing to do with flangeways, but thought I'd throw that into the discussion!

There are a lot of differences in the new Streamline points in addition to the flangeways. The spring is back underneath now, the blade pivots are different and the little contact tabs on the blades have gone (never were on the code 75 ISTR).

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Corrections and Notes.

Oh dear, Apologies I am going away from the OP...

However..

 

On 22/08/2020 at 19:00, Ravenser said:

It's worth at least trying to document the origins of EM. You might well be right about Metropolitan Junction being to 18.0mm gauge. I think Peter Denny wrote that the 18.2mm on Buckingham originated from his home made curve tool - a piece of  square timber with cuts sawn into it so it could be flexed into a curve

 

I received an e-mail from Richard Stevenson, who is following this thread but is not a member. He has put together the history of EM gauge, and sent me his latest draft. An earlier version appeared on the old EMGS website, but was not included on the current version.

 

Having read that and about the developments of 00 here, I think that the story of track standards is quite an interesting tale, if a little technical.

However, Richard made a couple of points in relation to my earlier (half informed) comments and I quote parts of his e-mail to aide clarity.

 

"the MRC's [Model Railway Constructor] "British Model Railway Standards Bureau" proposals of 1936... is not to be confused with the 1941 organisation, which is the "British Railway Modelling Standards Bureau" (Note the changed order of the initials), although the former clearly was the starting point of the development of the EM and HO standards of the latter."

 

"I am still not entirely clear about the sequence of events leading to the increase in gauge to 18.2 mm. The table with the 0.2 mm tolerances appears to have been a very late addition to the "Technical Note", some time after the 18.2 mm gauge SMP track had appeared. Possibly the original intention was simply to allow the SMP track to be within tolerance rather than increase the nominal gauge."

 

"MJ [Metropolitan Junction] has quite generous gauge widening on curves, up to 18.4 mm in places. I suspect that Mr Williams was aware of Peter Denny's 1950 article. There is not much straight track on the early parts of the layout and most of that was in a poor state and had to be re-soldered. There is still a short length of straight track which has not required the application of a soldering iron and that has a gauge of 18.1 mm."

 

 

On 22/08/2020 at 19:12, Ravenser said:

That , I suspect, is why code 75 has never really displaced code 100. People wouldn't buy it, because they assumed it was too fine - but Peco made it just the same as code 100 so there was no real advantage . Then they wouldn't breathe a whisper of the dimensions for fear of frightening the horses.

 

Result was they got the worst of all worlds commercially....

 

This is exactly what happened. The model railway club that I was a member of at the time were building a new layout. Some of us were pushing for the installation of finer (code 75) track. The older members who had collections of Wren, Triang and Hornby Doublo etc resisted this as they didn't want to re-wheel their stock. The final nail came we ran a test using SMP 00 track (ok not Peco, but we were being set up to fail) with a Wrenn loco. 

The clatter of flanges on chairs did the job and code 100 was used.

(Then there were mutterings that the club should be using 3 rail, but the door to the clubhouse was rapidly closing behind me as I found my way to EM)

 

Finally, I'll leave you with this, taken from Richards unpublished notes. It is about a survey conducted by the Model Railway News as to what the common 00 standard should be...

 

"In the November 1926 issue a postcard ballot was called on readers’ preferences, the alternatives offered being 3.5mm scale with a 5/8-in gauge or 4mm scale with a 19mm gauge.

 

In December 1926, MRN printed the results of the ballot: "At the time of writing we have received 131 votes divided as follows: 3.5mm and 5/8" gauge, 106 votes; 4mm and 19mm gauge, 13 votes; 4mm and 16.5mm gauge, 2 votes."

"

[5/8" is 15.88mm]

 

16.5mm at 4mm scale, it will never catch on!

 

Andy

 

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1 hour ago, brightspark said:

,,,,

 

This is exactly what happened. The model railway club that I was a member of at the time were building a new layout. Some of us were pushing for the installation of finer (code 75) track. The older members who had collections of Wren, Triang and Hornby Doublo etc resisted this as they didn't want to re-wheel their stock. The final nail came we ran a test using SMP 00 track (ok not Peco, but we were being set up to fail) with a Wrenn loco. 

The clatter of flanges on chairs did the job and code 100 was used.

(Then there were mutterings that the club should be using 3 rail, but the door to the clubhouse was rapidly closing behind me as I found my way to EM)

 

Finally, I'll leave you with this, taken from Richards unpublished notes. It is about a survey conducted by the Model Railway News as to what the common 00 standard should be...

 

"In the November 1926 issue a postcard ballot was called on readers’ preferences, the alternatives offered being 3.5mm scale with a 5/8-in gauge or 4mm scale with a 19mm gauge.

 

In December 1926, MRN printed the results of the ballot: "At the time of writing we have received 131 votes divided as follows: 3.5mm and 5/8" gauge, 106 votes; 4mm and 19mm gauge, 13 votes; 4mm and 16.5mm gauge, 2 votes."

"

[5/8" is 15.88mm]

 

16.5mm at 4mm scale, it will never catch on!

 

Andy

 

 

I have a Wrenn Class 20 from 1978 - it's flanges are too deep to run on code 75 (It also draws an amp and the motor bogie tips underload..) . Il Griffon's videos imply that genuine pre 1965 HD may have had shallower flanges than later production by Wrenn

 

It's starting to look as if standards at Triang, Triang-Hornby and Wrenn may have shifted back and forth at different times and never been properly documented

 

I was aware of the 1926 MRC poll - that seems to be conclusive evidence that "American OO" actually originated here in the mid 1920s. The Americans must have picked up HO and 19mm OO from us soon after - I can't see any other explanation of how they got where they did

 

Edited by Ravenser
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Dublo Class 20s also tend to tip their motor bogies. Something to do with traction tyres on both wheels on one axle only of the power bogie I suspect. The 2 rail version had pick up problems (not surprising looking at the design on the non powered bogie!) and was withdrawn from sale. Wrenn altered it to a non motored version of the power bogie, but how successful this was I don't know, as my two are both Dublo 3 rail. Why they didn't put a traction tyre on both axles like everyone  else is a mystery. They shouldn't draw an amp though. Dublo controllers are rated 8 or 9 VA. The fuses in the Bakelite cased transformers were 1 amp. 'Were' because these things have rubber insulated mains leads and are past their 'use by' date (by about 45 years).

 

AFAIK Wrenn driving wheels are the same as Dublo. I've never found any difference (apart from the lack of nickel plating on early (pre 2 rail) wheels. Earlier (pre1954) have a smaller diameter axle stub for fitting the wheels but otherwise are the same. I mixed them happily when I 2 railed mine in the sixties. (This heresy has since been reversed!). The carrying/rolling stock wheels are a different matter. Wrenn wheels have a separate tyre on a plastic centre. The nickel tyre makes them look coarse (black paint cures that), but they measure 1mm the same as Dublo (necessary to run on Dublo track with its filled in flangeways).

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8 hours ago, Il Grifone said:

Dublo Class 20s also tend to tip their motor bogies. Something to do with traction tyres on both wheels on one axle only of the power bogie I suspect. The 2 rail version had pick up problems (not surprising looking at the design on the non powered bogie!) and was withdrawn from sale. Wrenn altered it to a non motored version of the power bogie, but how successful this was I don't know, as my two are both Dublo 3 rail. Why they didn't put a traction tyre on both axles like everyone  else is a mystery. They shouldn't draw an amp though. Dublo controllers are rated 8 or 9 VA. The fuses in the Bakelite cased transformers were 1 amp. 'Were' because these things have rubber insulated mains leads and are past their 'use by' date (by about 45 years).

 

AFAIK Wrenn driving wheels are the same as Dublo. I've never found any difference (apart from the lack of nickel plating on early (pre 2 rail) wheels. Earlier (pre1954) have a smaller diameter axle stub for fitting the wheels but otherwise are the same. I mixed them happily when I 2 railed mine in the sixties. (This heresy has since been reversed!). The carrying/rolling stock wheels are a different matter. Wrenn wheels have a separate tyre on a plastic centre. The nickel tyre makes them look coarse (black paint cures that), but they measure 1mm the same as Dublo (necessary to run on Dublo track with its filled in flangeways).

It's not the traction tyres, the bogies still tip under load when completely re-wheeled.

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1 minute ago, Michael Edge said:

It's not the traction tyres, the bogies still tip under load when completely re-wheeled.

 

Then it will be the suspension (or lack of it). A pivot screw high up in the body is asking for trouble. Some sort of spring is probably the answer.

Many model diesels and electrics have a cut-out in the floor in which the bogie rotates and is thereby prevented from excessive tilting and transmits the load well down so as not to encourage it in the first place.

 

 

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