Why Would I Choose 00-SF ?

[Pacific231G]

Hi David,

 

NMRA RP25/110 wheels, i.e. RTR wheels, work just fine on 4-SF track provided the back-to-back setting is within limits. Which for such wheels is 14.4mm MAX, and the same minimum as all wheels, 14.3mm MIN. The great majority of RTR wheels do fall within those limits as supplied, but occasionally some wheels may need adjustment. The true maximum is the 15.2mm MAX back-to-flange dimension, so where flanges are thinner than 0.8mm the back-to-back can increase a little beyond 14.4mm accordingly.

 

All this has been posted many, many times on RMweb, and is fully detailed at: http://4-sf.uk

 

Scroll down to "Setting wheels for 4-SF".

 

regards,

 

Martin.

 

Thanks Martin

I knew that RP25/110 wheelsets would run on 4-SF; it was your phrase optimum wheel profile that struck me and wondered whether, if the back to backs are OK,  the difference between Romford etc. wheels and RP25/110 was marginal or significant. Though probably of no interest to anyone else here I use Kadee couplers and, particularly with four wheel wagons, the way wheel sets track through pointwork can be significant and a potential advantage of using a slightly narrowed gauge.

Edited October 15, 2015 by Pacific231G

[martin_wynne]

I knew that RP25/110 wheelsets would run on 4-SF; it was your phrase optimum wheel profile that struck me and wondered whether, if the back to backs are OK,  the difference between Romford etc. wheels and RP25/110 was marginal or significant.

 

Hi David,

 

I was thinking there of the effects of the flange thickness. With RTR wheels the flange thickness is 0.8mm and back-to-back 14.4mm. That leaves only 0.2mm running clearance on 16.2mm gauge. Which is fine for straight track and gentle curves, in fact providing very steady running. But it is at the bottom end of the range for sharper curves. That's why it is important to allow some gauge-widening on such curves, or use 16.5mm flexi track for sharp curves.

 

Romford/Markits wheels have thinner 0.7mm flanges, and when set at 14.5mm back-to-back the running clearance on 16.2mm gauge is 0.3mm -- a 50% increase over RTR wheels and a bit more freedom to use sharper curves at normal 16.2mm gauge. The thinner flanges also allow an increased angle of attack in the 1.0mm flangeway, where this might be needed for vehicles having a long fixed wheelbase.

 

Finer kit wheels such as Ultrascale with 0.6mm flanges at 14.6mm back-to-back allow even more running clearance on 16.2mm gauge at 0.4mm. This is double that of RTR wheels and rather more than strictly needed, so running when being propelled is not as steady as it might be. Also their narrower 2.3mm width is approaching the limit for full support through crossings if prototypical blunt-nose crossings are fully modelled.

 

Bear in mind that the current EMGS standard was created specifically for Romford/Markits wheels, so in reducing it by 2mm the same applies to 4-SF ("EM minus 2"). It was just a lucky accident that RTR NMRA/110 wheels were discovered to run well on there too.

 

regards,

 

Martin.

[Pacific231G]

Hi David,

 

I was thinking there of the effects of the flange thickness. With RTR wheels the flange thickness is 0.8mm and back-to-back 14.4mm. That leaves only 0.2mm running clearance on 16.2mm gauge. Which is fine for straight track and gentle curves, in fact providing very steady running. But it is at the bottom end of the range for sharper curves. That's why it is important to allow some gauge-widening on such curves, or use 16.5mm flexi track for sharp curves.

 

Romford/Markits wheels have thinner 0.7mm flanges, and when set at 14.5mm back-to-back the running clearance on 16.2mm gauge is 0.3mm -- a 50% increase over RTR wheels and a bit more freedom to use sharper curves at normal 16.2mm gauge. The thinner flanges also allow an increased angle of attack in the 1.0mm flangeway, where this might be needed for vehicles having a long fixed wheelbase.

 

Finer kit wheels such as Ultrascale with 0.6mm flanges at 14.6mm back-to-back allow even more running clearance on 16.2mm gauge at 0.4mm. This is double that of RTR wheels and rather more than strictly needed, so running when being propelled is not as steady as it might be. Also their narrower 2.3mm width is approaching the limit for full support through crossings if prototypical blunt-nose crossings are fully modelled.

 

Bear in mind that the current EMGS standard was created specifically for Romford/Markits wheels, so in reducing it by 2mm the same applies to 4-SF ("EM minus 2"). It was just a lucky accident that RTR NMRA/110 wheels were discovered to run well on there too.

 

regards,

 

Martin.

Thanks Martin

That's really useful. Most of my more modern stock is RTR but I have a number of older vehicles where I've replaced the original pizza-cutter wheels with Romford and other finer scale wheels.

[Ravenser]

Hi David,

 

I was thinking there of the effects of the flange thickness. With RTR wheels the flange thickness is 0.8mm and back-to-back 14.4mm. That leaves only 0.2mm running clearance on 16.2mm gauge. [Emphasis added when quoting] Which is fine for straight track and gentle curves, in fact providing very steady running. But it is at the bottom end of the range for sharper curves. That's why it is important to allow some gauge-widening on such curves, or use 16.5mm flexi track for sharp curves.

 

Romford/Markits wheels have thinner 0.7mm flanges, and when set at 14.5mm back-to-back the running clearance on 16.2mm gauge is 0.3mm -- a 50% increase over RTR wheels and a bit more freedom to use sharper curves at normal 16.2mm gauge. The thinner flanges also allow an increased angle of attack in the 1.0mm flangeway, where this might be needed for vehicles having a long fixed wheelbase.

 

Finer kit wheels such as Ultrascale with 0.6mm flanges at 14.6mm back-to-back allow even more running clearance on 16.2mm gauge at 0.4mm. This is double that of RTR wheels and rather more than strictly needed, so running when being propelled is not as steady as it might be. Also their narrower 2.3mm width is approaching the limit for full support through crossings if prototypical blunt-nose crossings are fully modelled.

 

.......

 

 

This goes to the heart of my concern with what you are promoting. You are stripping out clearances and working tolerances to the point where intermittent binding somewhere becomes well-nigh inevitable. The whole layout ends up on hairs-breadth clearances at best - and the moment that anything is sub-optimum , you're stuffed

 

You accept that clearances are very tight with RTR wheels - but in fact the picture is even worse, because "tight" wheelsets down to 14.3mm are quite common on RTR : most Bachmann locos will have one wheelset like that in my experience. That immediately wipes out half  the limited clearance at the check span. You are down to 0.1mm total clearance, or an average of 0.05mm each side. And you've repeatedly said that B2Bs down to 14.3mm are okay on OO-SF. These minimal clearances aren't exceptional cases - they will be commonplace - and you're expecting the whole wheel/rail interface system to work with complete reliability under such minimal clearances

 

Critically you have very restricted clearances for the RP25/110 flange through the flangeway and very restricted clearances  across the check span. It may not be possible for the wheelset to satisfy both the very narrowly defined constraints simultaneously. At  which point  something must come off. This is not a recipe for reliable running

 

There is now independent testimony from Brian Kirby that this is a real issue in practice:

 

...another snag was he built his point frogs tighter than most (as mentioned above), so regular unturned Romfords could hesitate slightly in a few places, just look at the tolerances quoted above in a previous post!

 

 

That's with Romfords, and - as you've just explained  - available clearances with RP25/110 are substantially reduced below those available with Romfords. 

 

When you add the inevitable slight variations that must arise when building points by hand , this is asking for trouble

 

 

A further issue arises from this. You've repeatedly said that the minimum acceptable radius for OO-SF is the same as EM - ie 2'6". But you accept above that the path of an RP25/110 wheelset through a 1.0mm flangeway is much more severely constrained than that of a Gibson/Ultrascale wheelset, to the EM 1979 profile - which is the wheel-standard intended for use with 1.0mm flangeways (In fact you note that RP25/110 is two levels tighter in terms of clearances than Gibsons )

 

You point out the substantially reduced working clearances this creates - but the corollary must be that the minimum workable radius for OO-SF/4-SF using RP25/110 wheelsets - in other words when running RTR stock - must be significantly larger than for EM gauge. The sharp reduction in available clearances suggests the true minimum radius for OO-SF could be well above 3'  

 

Put another way - what radius curve is necessary to run a RTR Bachmann ROD 2-8-0 reliably in OO-SF? Has anyone actually tried this out in terms of extensive operation and reliable running while hauling a train? You are promoting a standard without yourself having significant experience of it in practice - you don't have a layout in OO-SF yourself, and I suspect you don't own much RTR in OO 

 

 

Bear in mind that the current EMGS standard was created specifically for Romford/Markits wheels, so in reducing it by 2mm the same applies to 4-SF ("EM minus 2"). It was just a lucky accident that RTR NMRA/110 wheels were discovered to run well on there too

 

You've made this or a similar comment a couple of times .

 

I've always understood that the EM track standards are meant to fit the EM wheel standard, represented by the 1979 EM wheel profile, and embodies in Gibson and Ultrascale wheels

 

You appear to be advocating the use in EM  of coarser , and thicker flanged wheels (ie Romfords)  than the EMGS wheel standards define.

 

This looks very much like an 18.2mm gauge version of Martin Goodall's infamous "EM-P4", and all the comments above about the problems arising from reduced clearances apply - albeit less acutely than with RP25/110

 

At the same time, you've strongly emphasised the use of Gibson wheels in OO , and rebuked me for suggesting that it would be sensible to stick to Romfords to reduce any risk of drop it, as representing me trying to obstruct people improving their models.

 

To claim that Gibsons are too fine for EM but highly suitable and desirable in OO is bizarre.

 

But there is an underlying common push to strip out all the working clearances and tighten everything to within a hairsbreadth of seizing up

[martin_wynne]

This goes to the heart of my concern with what you are promoting.

 

Don't use it then. Simple.

 

And I am not "promoting" it, I am simply explaining it, in response to questions about it. I have also explained 00-BF at the same time.

 

The EM situation is more complex than you claim. The 18.2mm gauge came about in the 1960s because of the need to use Romford wheels. But some EM modellers continued to use the original BRMSB 18.0mm gauge. The 1979 wheel profile was a compromise to allow running on both gauges at the same 16.5mm back-to-back.

 

Just to repeat -- if you don't like 4-SF, don't use it.

 

Martin.

Edited October 16, 2015 by martin_wynne
typo

[Semi Fast]

As the OP, I think I now finally have the answer. I'm giving up. I will be using Hornby set track.

 

On the off-chance that I change my mind, I shan't be telling a soul about it or daring to ask for advice.

[dasatcopthorne]

Ravenser

 

or

 

Stephen.

 

You said "You are promoting a standard without yourself having significant experience of it in practice"

 

 

You are finding fault with 00-sf / 4-sf without having any significant experience of it in practice.

 

Dave

[hayfield]

This goes to the heart of my concern with what you are promoting. You are stripping out clearances and working tolerances to the point where intermittent binding somewhere becomes well-nigh inevitable. The whole layout ends up on hairs-breadth clearances at best - and the moment that anything is sub-optimum , you're stuffed

 

You accept that clearances are very tight with RTR wheels - but in fact the picture is even worse, because "tight" wheelsets down to 14.3mm are quite common on RTR : most Bachmann locos will have one wheelset like that in my experience. That immediately wipes out half  the limited clearance at the check span. You are down to 0.1mm total clearance, or an average of 0.05mm each side. And you've repeatedly said that B2Bs down to 14.3mm are okay on OO-SF. These minimal clearances aren't exceptional cases - they will be commonplace - and you're expecting the whole wheel/rail interface system to work with complete reliability under such minimal clearances

 

Critically you have very restricted clearances for the RP25/110 flange through the flangeway and very restricted clearances  across the check span. It may not be possible for the wheelset to satisfy both the very narrowly defined constraints simultaneously. At  which point  something must come off. This is not a recipe for reliable running

 

There is now independent testimony from Brian Kirby that this is a real issue in practice:

 

 

That's with Romfords, and - as you've just explained  - available clearances with RP25/110 are substantially reduced below those available with Romfords. 

 

When you add the inevitable slight variations that must arise when building points by hand , this is asking for trouble

 

 

A further issue arises from this. You've repeatedly said that the minimum acceptable radius for OO-SF is the same as EM - ie 2'6". But you accept above that the path of an RP25/110 wheelset through a 1.0mm flangeway is much more severely constrained than that of a Gibson/Ultrascale wheelset, to the EM 1979 profile - which is the wheel-standard intended for use with 1.0mm flangeways (In fact you note that RP25/110 is two levels tighter in terms of clearances than Gibsons )

 

You point out the substantially reduced working clearances this creates - but the corollary must be that the minimum workable radius for OO-SF/4-SF using RP25/110 wheelsets - in other words when running RTR stock - must be significantly larger than for EM gauge. The sharp reduction in available clearances suggests the true minimum radius for OO-SF could be well above 3'  

 

Put another way - what radius curve is necessary to run a RTR Bachmann ROD 2-8-0 reliably in OO-SF? Has anyone actually tried this out in terms of extensive operation and reliable running while hauling a train? You are promoting a standard without yourself having significant experience of it in practice - you don't have a layout in OO-SF yourself, and I suspect you don't own much RTR in OO 

 

 

You've made this or a similar comment a couple of times .

 

I've always understood that the EM track standards are meant to fit the EM wheel standard, represented by the 1979 EM wheel profile, and embodies in Gibson and Ultrascale wheels

 

You appear to be advocating the use in EM  of coarser , and thicker flanged wheels (ie Romfords)  than the EMGS wheel standards define.

 

This looks very much like an 18.2mm gauge version of Martin Goodall's infamous "EM-P4", and all the comments above about the problems arising from reduced clearances apply - albeit less acutely than with RP25/110

 

At the same time, you've strongly emphasised the use of Gibson wheels in OO , and rebuked me for suggesting that it would be sensible to stick to Romfords to reduce any risk of drop it, as representing me trying to obstruct people improving their models.

 

To claim that Gibsons are too fine for EM but highly suitable and desirable in OO is bizarre.

 

But there is an underlying common push to strip out all the working clearances and tighten everything to within a hairsbreadth of seizing up

 

 

I am echoing Martins comments, if you have concerns don't use it. Its in the hand built track section of this forum so is unlikely to impinge on the RTR section of the hobby. For my interests (and many other who subscribe to this part of the web site) it works and looks far better that the toy train track available out of the box.

 

Now to go on the attack of your beloved gauge as you seem to love to rubbish these set of standards why should I use any of the 2 GOGA track standards.

 

1 Why should I use GOGA intermediate standards with the overly large gaps through the check rails, flangeways and frogs, the turnouts and crossings look in my humble opinion awful with those large gaps

 

2  GOGA fine, OK the track looks much better with the finer check rails, flangeways and frogs gaps. On looks its great but then if I want a lot of stock to work through it I now have to start re-gauging a lot of my stock. If I wanted to re-gauge my stock I would be mad to do it to GOGA fine but do it to EM gauge standards as that would go most of the way in answering the narrow gauge og 00 standards.

 

Now getting back to the OP's question ( to remind you as you seem to have ignored it "Why Would I Choose 00-SF" )  , to avoid the above two reasons

 

Here is a question you and others may also like to answer Why do I now steer away from the GOGA stand at shows?

[hayfield]

As the OP, I think I now finally have the answer. I'm giving up. I will be using Hornby set track.

 

On the off-chance that I change my mind, I shan't be telling a soul about it or daring to ask for advice.

 

Semi Fast

 

What a spoil sport you are, just think of the hours of pleasure you have given some, best of all the exact opposite of what the two dissenters want, which is loads of publicity for 00sf.

 

I remember one financial organisation being absolutely slated in a TV program. only to be advertising a few weeks later "as seen on XYZ program" All publicity ends up being good publicity When did you last see a thread about another 00 gauge set of standards recently?

[Semi Fast]

Semi Fast

 

What a spoil sport you are, just think of the hours of pleasure you have given some, best of all the exact opposite of what the two dissenters want, which is loads of publicity for 00sf.

 

I remember one financial organisation being absolutely slated in a TV program. only to be advertising a few weeks later "as seen on XYZ program" All publicity ends up being good publicity When did you last see a thread about another 00 gauge set of standards recently?

Well, I'd had a rubbish day and a couple (or more) glasses of wine when I read the latest missive from the double-oh police. I've ignored the ranting as much as possible, read and understood the genuine debate - and you know what? I want to try building my own track to 00-SF/4-SF/EM -2/The Devil's Gauge. I Don't want to try and make anyone else use it, I don't want to "campaign" on it's behalf, I have no intention of making absolute statements about how good (or bad) it is. What I would like is to engage in a constructive manner with others who have already (or intend) to use it.

 

Too much to ask?

Edited October 17, 2015 by Semi Fast

[gordon s]

Please ask away Andrew.  I, along with several others will be only too pleased to answer your questions.  

 

Between us we have years of experience, a lot of knowledge, a ton of common sense and most importantly, experience of  building pointwork in 00-SF and then running RTR and kit locos on 00-SF trackwork.

 

It amazes me that both of the two major antagonists on 00-SF threads have no experience of building 00-SF pointwork and have no intention of using it.  Beats me why they have so much to say about it....

Edited October 19, 2015 by gordon s

[Arthur]

Too much to ask?

Sadly Andrew, at least as far as one or two are concerned, it does appear to be too much to ask.

 

One or two who seem to feel that they have a self appointed mandate to 'police' the modelling of others.

[The Stationmaster]

Please ask away Andrew.  I, along with several others will be only too pleased to answer your questions.  

 

Between us we have years of experience, a lot of knowledge, a ton of common sense and most importantly, experience of  building pointwork in 00-SF and then running RTR and kit locos on 00-SF trackwork.

 

It amazes me that neither of the two major antagonists on 00-SF threads have no experience of building 00-SF pointwork and no intention of using it.  Beats me why they have so much to say about it....

Could we perhaps have a  separate 'constructional hints & help' thread Gordon - sticking to exactly that and with the naysayers duly ploughing their furrows elsewhere?   

[Pacific231G]

 

A further issue arises from this. You've repeatedly said that the minimum acceptable radius for OO-SF is the same as EM - ie 2'6". But you accept above that the path of an RP25/110 wheelset through a 1.0mm flangeway is much more severely constrained than that of a Gibson/Ultrascale wheelset, to the EM 1979 profile - which is the wheel-standard intended for use with 1.0mm flangeways (In fact you note that RP25/110 is two levels tighter in terms of clearances than Gibsons )

You point out the substantially reduced working clearances this creates - but the corollary must be that the minimum workable radius for OO-SF/4-SF using RP25/110 wheelsets - in other words when running RTR stock - must be significantly larger than for EM gauge. The sharp reduction in available clearances suggests the true minimum radius for OO-SF could be well above 3'  

 

Put another way - what radius curve is necessary to run a RTR Bachmann ROD 2-8-0 reliably in OO-SF? Has anyone actually tried this out in terms of extensive operation and reliable running while hauling a train? You are promoting a standard without yourself having significant experience of it in practice - you don't have a layout in OO-SF yourself, and I suspect you don't own much RTR in OO

 

I wasn't aware that Martin was promoting anything.

The minimum radius question is surely a red herring because if you need to use a curve tighter than long wheelbase stock is comfortable with then you simply increase the gauge. Since the purpose of 00- SF is as I understand it to enable a layout with finer clearances to use RTR wheelsets designed for  16.5 mm gauge without any regauging (beyond correcting manufacturers' errors) then widening the gauge to that or a bit more for tighter curves is always an option. 

 

I'm not sure if its relevant to this discussion but in the late forties and early fifties the received wisdom for 00 built to BRMSB standrds seems to have been to use a minimum radius of 30ins  on plain track but a minimum of 36" for pointwork and most point kits from that time were mostly for a nominal 36 inch radius. I've just been reading some early articles on track construction by Peter Denny who mentions using curve templates of 36 inches "and others" (I'm guessing that 36ins was probably the smallest but he doesn't say) for point construction in EM.

 

BTW one area where I can see the use of 16.2mm gauge being particularly useful is for inset track as with standard clearances the flangeways on say a quayside do look far too large

Edited October 17, 2015 by Pacific231G

[Derekstuart]

Very restraint, I though.

Don't use it then. Simple.

 

And I am not "promoting" it, I am simply explaining it, in response to questions about it. I have also explained 00-BF at the same time.

 

The EM situation is more complex than you claim. The 18.2mm gauge came about in the 1960s because of the need to use Romford wheels. But some EM modellers continued to use the original BRMSB 18.0mm gauge. The 1979 wheel profile was a compromise to allow running on both gauges at the same 16.5mm back-to-back.

 

Just to repeat -- if you don't like 4-SF, don't use it.

 

Martin.

[trustytrev]

Hello,

    

 

Well, I'd had a rubbish day and a couple (or more) glasses of wine

 

I really like Australian Shiraz. Whats yours?

trustytrev.

[Semi Fast]

Currently, an Chilean Merlot, which the wife chose (because it was "a bargain"). Not bad, but favourite at the moment is Yellow Tail Malbec - also Australian. Sublime. But after watching today's rugby, I may have to boycott Aussie wine. Scotland would be my least favoured of the home sides, but they were the last hope. Dodgy decision in the last minute?

[Derekstuart]

After learning today that my J72 collection (yes collection), WD Austerity, 9F, B1, V1/3 and V2 will need kit or hand built replacement chassis as they cannot be converted to P4 without lots of surgery, I have to say that 4SF is looking even more attractive.

[hayfield]

Derek

 

An old Mainline J72 is my 00 gauge test loco, all 3 sets have different Back to back. The rational is that if it works then every thing else will, but that's for 00 universal/intermediate. However a Mainline Peak, Bachmann 08 are fine and Airfix class 31 are all fine in 00sf.

 

I would have thought EM gauge might have served your purposes better, but with fancy valve gear to take into consideration it may be a good call to stick with 00. It might be worth building a couple of copperclad turnouts first just to check that your stock is compatible with 00sf

[Junctionmad]

 

 

Any questions at the back? Thought not......

 

polybear

Ive said it elsewhere, - clever bear......

[hayfield]

Interesting, certainly shows that he has an axe to bear and mus be very worried about the effect 00sf is presumably having of their beloved standards. 

 

How very different it could have been had the DOAG been more welcoming to other 00 gauge modellers, or is this just one person acting on his own ? 

[Derekstuart]

Talk about pouring petrol on fires...

 

I have a mug of tea, some mars bars and my finger on constant F5 refresh for this.

[polybear]

 

How very different it could have been had the DOAG been more welcoming to other 00 gauge modellers, or is this just one person acting on his own ?

 

Not sure - if it's "the official DOGA Line" ( I hope not - a shame if it is) then it doesn't paint the Association in a very good light IMHO.

Brian

[Derekstuart]

Brian

 

This is not the first time that someone here or on other forums has hidden their position and attacked someone else for having an opposing view.

 

I am a well known critic of one particular exhibition and found what I can only describe as harassment from an individual- and lo and behold, he is the one behind the exhibition- and yet he was making his points as if he was just an average modeller.

 

So this sort of thing goes on...

[Ravenser]

This goes to the heart of my concern with what you are promoting. You are stripping out clearances and working tolerances to the point where intermittent binding somewhere becomes well-nigh inevitable. The whole layout ends up on hairs-breadth clearances at best - and the moment that anything is sub-optimum , you're stuffed

 

You accept that clearances are very tight with RTR wheels - but in fact the picture is even worse, because "tight" wheelsets down to 14.3mm are quite common on RTR : most Bachmann locos will have one wheelset like that in my experience. That immediately wipes out half  the limited clearance at the check span. You are down to 0.1mm total clearance, or an average of 0.05mm each side. And you've repeatedly said that B2Bs down to 14.3mm are okay on OO-SF. These minimal clearances aren't exceptional cases - they will be commonplace - and you're expecting the whole wheel/rail interface system to work with complete reliability under such minimal clearances

 

Critically you have very restricted clearances for the RP25/110 flange through the flangeway and very restricted clearances  across the check span. It may not be possible for the wheelset to satisfy both the very narrowly defined constraints simultaneously. At  which point  something must come off. This is not a recipe for reliable running

 

There is now independent testimony from Brian Kirby that this is a real issue in practice:

 

 

That's with Romfords, and - as you've just explained  - available clearances with RP25/110 are substantially reduced below those available with Romfords. 

 

When you add the inevitable slight variations that must arise when building points by hand , this is asking for trouble

 

 

A further issue arises from this. You've repeatedly said that the minimum acceptable radius for OO-SF is the same as EM - ie 2'6". But you accept above that the path of an RP25/110 wheelset through a 1.0mm flangeway is much more severely constrained than that of a Gibson/Ultrascale wheelset, to the EM 1979 profile - which is the wheel-standard intended for use with 1.0mm flangeways (In fact you note that RP25/110 is two levels tighter in terms of clearances than Gibsons )

 

You point out the substantially reduced working clearances this creates - but the corollary must be that the minimum workable radius for OO-SF/4-SF using RP25/110 wheelsets - in other words when running RTR stock - must be significantly larger than for EM gauge. The sharp reduction in available clearances suggests the true minimum radius for OO-SF could be well above 3'  

 

Put another way - what radius curve is necessary to run a RTR Bachmann ROD 2-8-0 reliably in OO-SF? Has anyone actually tried this out in terms of extensive operation and reliable running while hauling a train? You are promoting a standard without yourself having significant experience of it in practice - you don't have a layout in OO-SF yourself, and I suspect you don't own much RTR in OO 

 

 

You've made this or a similar comment a couple of times .

 

I've always understood that the EM track standards are meant to fit the EM wheel standard, represented by the 1979 EM wheel profile, and embodies in Gibson and Ultrascale wheels

 

You appear to be advocating the use in EM  of coarser , and thicker flanged wheels (ie Romfords)  than the EMGS wheel standards define.

 

This looks very much like an 18.2mm gauge version of Martin Goodall's infamous "EM-P4", and all the comments above about the problems arising from reduced clearances apply - albeit less acutely than with RP25/110

 

At the same time, you've strongly emphasised the use of Gibson wheels in OO , and rebuked me for suggesting that it would be sensible to stick to Romfords to reduce any risk of drop it, as representing me trying to obstruct people improving their models.

 

To claim that Gibsons are too fine for EM but highly suitable and desirable in OO is bizarre.

 

But there is an underlying common push to strip out all the working clearances and tighten everything to within a hairsbreadth of seizing up

 

I notice nobody is prepared to comment on the factual issue - what are the implications of eroding the working clearances in this way???