EM/OO Fine standards applied to Irish 5'3" gauge track.

[Mayner]

I though it would be useful to apply the EMGS standard to Irish 5'3" gauge to help people weight up the pros and cons of modelling in 21mm gauge and to make an objective comparison between working to P4 or to EM/OO fine wheel and track standards.

In particular to dispel the misconception that 21mm EM profile wheel sets are substantially wider than P4 wheel sets and it is necessary to reduce the gauge to 20.2 (Irish EM)or increase clearances between splashers/side frames & w irons to accomodate the greater width.

EM & P4 standards were developed by groups of modelers in the UK who aspired to a higher standard of modelling than was achievable with models and components available in 4mm scale during the 1940s and the 1960s.  P4 adapted a wider gauge of 18.83 compared with the 18.2 adapted by the EM Gauge Society combined more significantly with more prototypical running tolerances and wheel profiles.

Closer running tolerances in combination with finer flanges and wheel tyres demand a more precise standard of baseboard, track and wheel assembly than required in EM or OO. Some form of springing or active suspension is usually required in P4 though not absolutely necessary if working to OO/EM standards.

One P4 modeler raised controversy in a recent-ish Model Railway Journal by running stock with EM profile wheels on P4 track in order to achieve reliable trouble free running.

21mm modelers appear to mainly work independently or in small groups and have tended to develop standards on their own initiative rather than  through groups.

Tony Miles pioneered fine scale 21mm developing a similar set of wheel and track standards more or less concurrently with the P4 Society. Tim Cramer published an article on modelling in 21mm in the Railway Modeller in 1972, using proprietary OO/EM wheels set at a back to back of 19.5mm.

I started working in 21mm in the mid 1980s building locos and stock though did not have time or space for a layout. I got involved with the MRSI Loughrea group when I returned to Ireland in the mid 1990s and had a pleasant surprise when my locos and stock some with quite fine wheel ran on Loughrea.

Interestingly I had no problems running locos and stock with EM/OO finescale wheels set at 19.5mm back to back through the pointwork on the Loughrea layout, though it was necessary to reduce the back to backs on wagons fitted with older wheels with a coarser profile to 19.3mm which correlates with the EM standard.  

Note on tyre width and back to back

One of the major differences between the P4 and EM gauge standards is that the P4 standard specifies min-max tolerances for back to back gauge and tyre width while the EM standard specifies specific values.

Provided the back to back gauge and tyre width does not exceed the standard the overall width of a 21mm OO/EM wheel set is marginally narrower than a 21mm P4 set at maximum tolerance. for back to back and tyre width.

In practice Ultrascale , Gibson OO/EM wheel sets do not exceed the 2.27mm tyre width specified in the standard and excessive wheelset width width is unlikely to be a problem.

Interestingly the majority of my steam locos are fitted with Sharman B profile wheels (alas no longer available!) these wheels have a tyre width of 2.07mm very close to the 2mm max specified in the P4 standard!

I have included WCG or Wheel Check Gauge (Back to back +1 Effective flange) although not identified in the EM Gauge Trackwork Standard 

In some of his works on trackwork and rolling stock, Iain Rice identified that the "Wheel Check Gauge" (distance measured between the rear of one flange to the face of the opposing flange) rather than the back to back gauge as the vital constant in assuring the correct relationship between wheels and track. The WCG becomes particularly important when wheels with different flange thicknesses are used on a layout (e.g. mixing scale wheels like Ultrascale & Gibson with universal wheels from rtr manufacturers).

 

Scalefour Digest 1 Track and Wheel Standards.pdf

EMF Standard for Irish Broad Gauge Track.pdf

Edited September 25, 2018 by Mayner

[merlinxlili]

Very good John! The bottom line appears to be that one can build track to 21mm P4 standards, but use EM section wheels and it works. Is that right?

The article in MRJ was written by a modeller who had built a large railway which suffered from persistent derailments. Apparently this is a relatively common problem at exhibitions which leads to complaints about unreliability, the need for constant fettling, etc. Needless to say there has been some debate on the subject. 

In my opinion this is a matter of horses for courses. Obviously it is pleasing to build a railway as accurately as possible and to develop skills as one goes along, but on the other hand few people have the luxury of being able to spend lots of time on their hobby, so a compromise has to be made. The mind's eye is a wonderful help for this, provided one doesn't take any close-up photographs which unfortunately the/my mind's eye refuses to accept. So my own conclusion so far is that I would like to build railway models as accurately as possible, within my limitations of time and skill, but also concentrating on what is visually important (obviously the thing has to work well). 

I also throw in the idea that for any prototype there are a number of things that really characterise it in a model, which are probably subjective to each modeller. So a modeller should try to get these details right, while many other aspects may be compromised with minimal effect. For me big clunky wheels, rods, etc, ruin the effect, so finer running gear is highly desirable.

I would like to build in 21mm gauge and make use of finescale track to achieve that delicate look. The use of EM wheels seems to be a great compromise, providing slender wheels with a much greater chance of them staying on the track. The S4 society have all the gauges needed for track and wheel set construction to P4 standards, including 21mm gauge. Maybe better not to mention that EM wheels might be used?

[Mayner]

2 hours ago, merlinxlili said:

Very good John! The bottom line appears to be that one can build track to 21mm P4 standards, but use EM section wheels and it works. Is that right?

I haven't tried running EM profile wheels on P4 track, so I can only take the author of the articles advice at face value.

I think the issue started with intermittent derailments when the authors grand children were visiting, similar problems occur on a high proportion of model railways regardless of gauge or standards when there are visitors about.

Visually there is little difference between 21mm point and crossing work laid to EM or P4 standards, the plain track will look exactly the same. The only real difference is that flangeways are 0.32-0.35mm narrower in P4 than EM not exactly noticeable at normal viewing distance.

Building large complex 21mm gauge layout in a short space of time is basically out of the question unless you are a Tony Miles that has the ability to recruit and manage a team of to build and operate a large layout.

I am not sure if the S4 Society currently supply track gauges and axles suitable for 21mm gauge.

[merlinxlili]

Yessir! Roller, triangular and flangeway gauges plus Brook-Smith back-to-back wheelset gauge are all available for 21mm.

[leslie10646]

The Scale Four Society do sell 21mm wheel sets , suitable W irons etc - Jeremy Sutter (who made several useful white metal kits in days of yore) runs their stores.

See ;

https://www.scalefour.org/stores/stores.html

Leslie

[David Holman]

Andy Cundick has been doing this on Valencia Harbour and latterly Courtmacsherry for years. Have had the pleasure of operating Valencia and the system works perfectly well. A pleasure to operate.

 Meanwhile, my own Fintonagh does exactly the same, albeit 7mm scale, but to 21mm gauge for 3' gauge. I've used 1mm flangeways on 900mm radius points, with 19- 19.5mm back to backs.

 What I have found is that, using 4mm finescale wagon wheels on code 83 flat bottomed rail is that there is a lot less margin for error than on Arigna Town, where Slater's 7mm scale wheels work really well on code 100 FB track. Derailments are virtually unknown, even though the gauge varies by up to +/- .5mm. This with a back to back on loco axles that Slater's quote as 33.98mm!

 On Fintonagh, tolerances are much tighter (using EM standards, as outlined by Mayner), so back to backs cannot be out more than 0.5mm max, or derailments occur on point crossings (frogs). However, apart from a degree of fettling to ensure tolerances are kept within these limits, all works well. 

 The moral of the story, as Andy will tell you, is that 21mm gauge does NOT require P4 standards. EM/4mm finescale is fine! 

 You still need to lay track carefully, but otherwise, it is no harder that doing 00. Whether your models are capable of running with wheels at 19mm back to backs is another matter, but 21mm gauge (or indeed 36.75mm in 7mm scale) looks so much better and if that appeals, this is so worth pursuing.

[Horsetan]

On 9/27/2018 at 12:23 AM, leslie10646 said:

The Scale Four Society do sell 21mm wheel sets , ...

No they don't.

[Andy Cundick]

Easy enough to make your own axles.Minidrill, grinding block and a bit of 2mm rod cut to length takes under a minute.Andy

[Mayner]

Ultrascale will supply 21mm loco and rolling stock wheel sets to order to either EM or S4 wheel profile. 

9 month order lead time but a very high quality product that will run through and probably outlast the buyer.

[DiveController]

6 hours ago, Mayner said:

Ultrascale will supply 21mm loco and rolling stock wheel sets to order to either EM or S4 wheel profile. 

9 month order lead time but a very high quality product that will run through and probably outlast the buyer.

If only someone would build 21mm flexitrack and even one basic short prototypical crossover (which is very large by all accounts, let alone the express crossover) or a basic non-prototypical crossover (most Hornby, Peco Bachmann crossovers fit into this category), it would make entry into 21mm gauge so much easier, Fine for fiddle yards and small layout but not practical to build anything larger than this form scratch 

[Horsetan]

On 9/25/2018 at 3:32 AM, Mayner said:

....One P4 modeller raised controversy in a recent-ish Model Railway Journal by running stock with EM profile wheels on P4 track in order to achieve reliable trouble free running.....

That could only be Martin Goodall.

[Horsetan]

On 20 November 2018 at 6:53 PM, Mayner said:

Ultrascale will supply 21mm loco and rolling stock wheel sets to order to either EM or S4 wheel profile. 

9 month order lead time.....

That lead time has now improved to 10 months.

[Mayner]

Just received delivery of 21mm wheel sets ordered in February. Main issue a bit like CIE ordering the second batch of Deutz  is that the rationale the wheel sets has changed during the past 10 months.

The intention was to order enough wheels for 1970s passenger train (Cravens, 1953 Buffet, BR van) and re-gauge a rake of IRM wagons which no longer fit in with the overall scheme of things.

The 3'1" disc and 3 hole wheels will end up under GSR era wagons which is much the same as when I was planning to re-gauge a rake of Airfix MK2D coaches nearly 20 years ago.

 

Wheels are certainly to a high standard , unlikeley to work loose on their axle or loose a tyre unlike some wheels at the scale end of the market.

I will probably go back to Ultrascale when I use up my stock of Sharman steam loco wheels.

Edited December 2, 2018 by Mayner

[merlinxlili]

John,

You mentioned somewhere that your previous 21mm project suffered from having insufficient separation of double tracks. What centre-to-centre measurement did you use and what would you recommend instead? How does 48.6 mm sound?

With respect to 21mm wheelsets can those from Gibsons not be used, available in OO, EM & P4 profiles? They have plastic centres and 21mm axles are not available from them, but that should not cause insurmountable problems.

[Horsetan]

10 hours ago, merlinxlili said:

...With respect to 21mm wheelsets can those from Gibsons not be used, available in OO, EM & P4 profiles? ..

Of course they can. Either cut your own axles, or wait up to 10 months for Ultrascale to cut them for you.

[Mayner]

On 12/5/2018 at 1:30 AM, merlinxlili said:

John,

You mentioned somewhere that your previous 21mm project suffered from having insufficient separation of double tracks. What centre-to-centre measurement did you use and what would you recommend instead? How does 48.6 mm sound?

With respect to 21mm wheelsets can those from Gibsons not be used, available in OO, EM & P4 profiles? They have plastic centres and 21mm axles are not available from them, but that should not cause insurmountable problems.

North Yard in New Zealand supply a 28mm 2.03dia blackened brass pin point axle @ $0.90NZ (app £0.48) Item 471 delivery approx 2 weeks postage app $15-20NZ per order. Northyard.co.nz North Yard wheels and axles are mainly intended for modelling S scale use.

I have used these axles successfully with Alan Gibson and Hornby wheels in 21mm gauge and with North Yard wheels in OO. 

An alternative is to extend a standard 26mm axle by cutting and sleeving with 2mm inside diameter brass tube available from Eileen's Emphorium in the UK.

I haven't worked out mimimum track centers for 21mm, distance will vary subject to a number of factors including track alignment, lineside structures, min vehicle width and length. 

The MGWR loading gauge specified a minimum of 6'2⅝" rail centre-rail centre between tracks, very close to the nominal 6' way or 24mm in 4mm

Distance between running roads needs to be increased above a min 24mm on curved trackage and between running lines and yard trackage and between tracks in yards where people were likely to be working.

I ran into problems with side swiping between 60'X9'6" coaches on curved track laid at a min radius of 3' and 24mm between tracks.

 

[merlinxlili]

Thank you John. As you say the distance between track centres seems to be as long as the proverbial piece of string. Having sniffed around the web for a bit, the best advice seems to be to test this out before you begin to design or lay track seriously, using your longest and widest rolling stock. For reference I found the 48 mm on Templot for 21mm track, while someone quoted the de facto separation for Peco set track as 64mm! Interestingly the GWR often had a more generous spacing because they had inherited much of their alignments from Mr Brunel, but otherwise the railway companies would have used as narrow trassees as possible to minimise the cost of buying land.

[DiveController]

That a pretty big range 'something greater than 24mm' - 48 mm

[Noel]

21mm fascinates me and one day far in the future I'd love to have a small shunting layout despite the apparent workload effort, skills, cost and equipment required to convert stock, the risk of unreliable track running. Are there more than 5 people operating 21mm in the UK and ROI?  It does look fab when well done, but it seems you'd need the skills of a talented jeweller to convert most RTR locos and rolling stock. My Hat is off and full of admiration for those who have successfully ploughed the 21mm gauge furrow, and especially for those who have built steam locos that run successfully on 21mm you deserve knighthoods, especially if brass.

[jhb171achill]

I was thinking that too, Noel. Maybe a fictitious Dublin & Blessington halt at a roadside - simple type of thing. A tram loco, a 4-wheel railcar, a tram or two to pull and a couple of goods vans would do.

Would anyone have any advice on a suitable four wheeled power bogie which could be easily amended to 21mm gauge, I wonder?

[murrayec]

Hi jhb

The spud motor lends it's self to conversion pretty easily, just replace the axles with longer ones, replace the pick-ups, and also the wheels need to be replace as the spud has stepped axles ends- down to 1.5mm!

Here are a few photos of the spud set up for a 21mm DART;-

Eoin

Edited December 7, 2018 by murrayec

[Mayner]

The choice between 21mm and OO is really about whether a person draws the more satisfaction from the technical and physical challenges of building to an odd-ball gauge or building and operating a layout using rtr stock.

For someone wanting to build a large layout within a reasonable time frame or a continuous run in a restricted space OO or even EM is probably a better option than 21mm gauge.

Mounting the layout near eye level and using Bullhead or Peco Code 75 track will reduce the narrow gauge look of OO gauge track. 

It should be possible to build an continuous run 21mm layout to OO standards with No 2 or No 3 radius curves and NMRA 110 wheels , but the gauge would have to be reduced below 21mm to provide sufficient splasher and cylinder clearance with steam locos which is probably not worth the effort, though a couple of modelers model Irish broad gauge on EM track.

(Templot) Martin Wynne has specifies a track gauge of 20.2mm with a 1mm flangeway gap  and a minimum recommended radius of 1000mm for Irish broad gauge track laid to EMGS standards.  The gauge was presumably reduced the risk of EMF wheels fouling steam loco splashers and coupling rods/crossheads on outside cylinder steam locos.

The flangeway clearances would have to be increased to 1.5mm and wider NMRA wheels and the gauge narrowed further to avoid the problem of the minimum radius is reduced to 600mm.

I don't know if any 5'3" gauge modeler has reduced the gauge to 20.2mm , clearances are tight but workable with Gibson & Ultrascale EMF profile wheels wheels.

 The distance between splashers/coupling rods cross heads on outside cylinders would have to be increased or the gauge reduced if you intend using steam locos with NMRA 110 profile wheels.

 

NMRA 110 profile wheels with b-b set 1t 19.3 fouling splashers on SSM J15. 

Edited December 8, 2018 by Mayner

[Mayner]

11 hours ago, jhb171achill said:

I was thinking that too, Noel. Maybe a fictitious Dublin & Blessington halt at a roadside - simple type of thing. A tram loco, a 4-wheel railcar, a tram or two to pull and a couple of goods vans would do.

Would anyone have any advice on a suitable four wheeled power bogie which could be easily amended to 21mm gauge, I wonder?

Both Steam Era Models (Black Beetle Motor Bogies) & Hollywood Foundry (Bull-Ant) in Australia will supply 21mm gauge motor bogies & chassis to order. Hollywood Foundry will produce chassis to any gauge upwards of N including 12mm for Irish 3' and English Broad Gauge for modelers who are in to that sort of thing.

[Noel]

This caught my attention  some years ago

Also this

 

Edited December 8, 2018 by Noel

[jhb171achill]

10 hours ago, Mayner said:

Both Steam Era Models (Black Beetle Motor Bogies) & Hollywood Foundry (Bull-Ant) in Australia will supply 21mm gauge motor bogies & chassis to order. Hollywood Foundry will produce chassis to any gauge upwards of N including 12mm for Irish 3' and English Broad Gauge for modelers who are in to that sort of thing.

Excellent! I'll check these out. Thanks!