Pendon-style track and wheels

[Geoff StennerParticipant]

Hello. Apologies if this has already been discussed ad nauseam. Has anyone tried what might be called EEM of late. I have wondered as , looking at the video and some shots of Gerry Beale’s ‘Maiden Newton’, I wondered if he had reduced the crossing gap on his turnouts.

With modern wheels, the earlier EM standards of 1mm crossing gauge could be reduced to .9mm or possibly .8mm with an expanded B-to-B to , say. 16.7 mm.

Does anyone here use the earlier dead-on 18mm gauge? I seem to remember the extra .2mm was added to accommodate the long-defunct Stephen Poole wheels in the 1970s, seemingly in irrelevancy now. What I am driving at is that could a small modification be made to improve the look of crossings while keeping the advantages of EM in terms of easier stock and loco conversions, along with the ability to use the slightly tighter-than-P4 curves that EM standards allow?

Any of your thoughts would be welcome as I’m fiddling with 4mm again after years in other scales, and have a divided opinion about what I might do, added to which a friend has gone back to EM after some years building in P4; both sets of standards equally worthy, but horses-for-courses comes to mind.

[Bob AllisonParticipant]

Geoff,

There is quite a long thread on the Templot forum which considers all the angles:

https://85a.uk/templot/archive/topics/topic_3380.php

Don’t worry if you’re not into Templot, the thread is quite unrelated to the Templot software.

I haven’t used these standards myself, but the principle seems sound.  I would be concerned with a check span of 16.4mm and back to back of 16.5mm, which leaves only 0.1mm tolerance for track building and wheel erection.  Your plan to use a slightly larger back to back feels like a good idea..

Still waiting to hear from someone who has actually built a layout to what Martin Wynne calls EM-SF….

Bob

PS I also returned to EM after many years working to P4. Never regretted it.

[Geoff StennerParticipant]

Hello, Robert. Thanks for your thoughts and the most useful link to the Templot site. Now in my autumnal years, and with a couple of ‘hair shirt’ layouts in other scales (one still under construction), I’m looking to have a bit more enjoyment without tears from the hobby. I have been tempted by the Grainge and Hodder baseboards , the curved ones usefully forming a two metre diameter circle, so allowing something like 3’2″ radius curves at the outer edge; getting tight in P4 but acceptable in EM. I have a ‘push-along’ Hornby T9 converted to P4 and it will take a 3′ curve at 19.1mm gauge on a small test piece I’ve thrown together, and I’ve also tried a P4 0-6-0 with 15′ 6″ wheelbase which seemed fine. However, we are at the cutting edge with these combinations.

I have a bizarre  interest in eight-coupled machines and large Edwardian/WW1 four-coupled (denied me in my other scales), and fancy watching them go round a circuit. I don’t feel it would be easy to get satisfactory running at those radii in P4, though doubtless someone has done it  and I’m not denying it is possible. However, I don’t want to be shooting for the moon any more. The Martin Wynne standards of 18mm for straights and turnouts, easing to 18.2mm on curves with 16.7mm B-to-B and .8mm crossing gap therefore seem a great compromise, as long as RTR wheels are not used. My experience with the T9 and other large-wheeled locos has lead me to believe that metal-centred wheels are a safer bet to minimise wobble and thus retain clearances in splashers on low footplates; fortunately, whilst completely un-trained formally I can use my small lathes for trueing or re-profiling.

Would be grateful to hear any other thoughts on this, and also whether true 18mm track gauges are available anywhere.

Thank you.

[Bob AllisonParticipant]

Geoff,

I would be surprised if 0-6-0s and 0-8-0s caused problems on curves of about 3ft radius, it’s easy to provide sufficient sideplay on the centre axle(s).  Problems are more likely to arise where there are bogies and /or pony trucks – see my post on this thread:

EM Gauge 90 degree Radius 2 curve

I’m having second thoughts about the wisdom of increasing the back-to-back and reducing the track gauge at the same time – I wonder if the wheels will be running on the radius between flange and tread.  The EMGS manual includes a dimensioned sketch of the recommended tread profile which should allow you to work it all out.  And here’s another link to a thread where “T-B-G” has actually built pointwork to EM-SF standards and run Gibson etc wheels with 16.5mm BTB successfully.  The text below the photos of his track is very pertinent.

https://www.rmweb.co.uk/topic/171990-manufacturing-some-em-sf-gauges/

I know that someone used to sell gauges for EM-SF but I don’t think they are available any more – I cannot find any on the web.  The link above has a dimensioned sketch of a suitable gauge which you should be able to turn up on your lathe.

Beginning to wonder if my new layout should be in EM-SF….

Bob

[Geoff StennerParticipant]

Thanks again, Bob. The pointwork in the photos via the link would be what I’d be aiming at. Re bogies on locos, yes, I agree. The push-along T9 still has virtually all the bogie side-swing which Hornby designed into it. The tighter P4 clearances keep the yawing down, and I think a weighted tender resting on the drawbar might also help to prevent front-end wobble. However, it is difficult to place on the track and one can feel the resistance being encountered against the wheels, but not so much that force is needed.

All in all, most interesting, and I’m grateful for your comments and links. I also take your point re the wider back-to-back, so  the George Watts B-to-B gauge will come in useful as it is adjustable for all the 4mm scale gauges; I think the only thing to do is try to build a point to EM-SF and experiment.

 

 

[John CutlerParticipant]

Many moons ago, the late Iain Rice suggested reducing flangeways to 0.9 mm or even 0.8mm in EM to improve appearances. I use a strip of 0.9mm thick aluminium in preference to the EMGS standard stainless steel gauge of 1mm. This works quite well provided one uses finescale wheels from Gibson etc. RTR wheels were not a good idea at the time  (I agreed with Joe Brook-Smith who upset the EMGS hierarchy) but I have not tried the new finer profiles now being produced by Hornby et al.
If you have some 1mm and 0.9mm strip to hand, try running them through the new EMGS B6 turnouts. If they are like mine, the flangeways are nearer to 0.9 mm wide than the EMGS official standard! My new Finetrax double slip (yet to be used in anger) has 1mm flangeways; I wonder if Wayne can be persuaded to produce EM-SF versions? Somehow I doubt it.

Bernard Weller promoted a wider BTB and Exactoscale sold a back-to-back gauge of 16.7mm for EM which I use in preference to the EM standard of 16.5mm. In practice I find that pushing wheels in to fit the gauge usually gives a 16.6mm BTB; it seems the plastic wheel centres bounce back? Anything between 16.5 and 16.7mm is acceptable to me; I refuse to believe the P4 guys can measure accurately and consistently to 2 decimal places of a millimetre! As Geoff says above, George Watts sells a variable BTB gauge which can be set to 16.7mm. My experience is that the wider BTB gives more reliable running. One result is that if your handbuilt point work is dodgy like mine, the wider BTB will quickly reveal anything narrow to gauge. My recommendation is to slightly widen the track gauge through any turnouts (even if you stick with the proper EMGS standards); be wary of relying solely on triangular gauges when doing this.

No doubt Martin will be along shortly to tell me the check gauge needs to be adjusted accordingly.

 

[Geoff StennerParticipant]

Again, thank you and most interesting. The late Mike Sharman was, I believe, sceptical about track gauges and I agree; he said that waving a hot soldering iron around at track building cannot guarantee correctness of gauge, and I confess to relying more on a pair of digital calipers to check gauge-the results can be surprising. A couple of gauges do, however, help with holding things in place.

I also agree with the gauging of plastic centred wheels in the theory of some ‘bounce’ if a gauge is forced between them too firmly.

I wonder if the EMGS might consider the re-introduction of an ’18mm dead’ track gauge for EM-SF? The flangeway can be set by a pair of .8mm drills held in a vee shape with tape, and the .8mm check chairs are already available.

[Paul WillisParticipant]

I refuse to believe the P4 guys can measure accurately and consistently to 2 decimal places of a millimetre!

 

As one of the P4 guys that is a member of the EMGS, I can assure you that it is just as easy to set a pair of wheels to 17.87mm as it is to 16.50mm.

It’s simply that for some reason EM modellers tend not to quote the second decimal place as though it doesn’t exist.  Like global warming, it’s still there, whether you believe in it or not…

My BTB gauge has been measured to the average of three micrometers and marked accordingly.  Of course it will never be 100% accurate to that measurement, but that is where the ability to build to a consistent standard is more relevant that being able to build to a spuriously accurate one.

HTH

Paul

• This reply was modified 1 year ago by Paul Willis.

[Paul WillisParticipant]

I also agree with the gauging of plastic centred wheels in the theory of some ‘bounce’ if a gauge is forced between them too firmly.

Which is why you should never use a gauge when it is a force-fit.  Even an interference fit is by definition distorting the parts involved.

What is needed is a close sliding fit.  If you have the ability to sense that, then your track and wheels should be true to dimension.

Best,

Paul

 

[Bob AllisonParticipant]

Hi Paul,

Good to hear from you again; after your post on 3rd July I feared that you might have abandoned this forum altogether.

Firstly, in fairness to you and the P4 chappies (I was one for 30 years and am still a member) I have never heard any of them claim to get anything right to a hundredth of a millimeter.  18.83 is a nominal dimension.

That said, I think most if not all would agree that the official EMGS standards are more forgiving of errors than P4.  Take back-to-back for instance: with accurately laid track and tyre profile as per official drawing, the back to back can vary between 16.25 and 16.65 without derailment (albeit with slightly rough running at the extremes).  Of course, the track will never be perfect, so this 0.4mm tolerance might better be viewed as being shared between track and wheels.  Also, EM flanges are nearly twice as deep as P4 flanges, so there is more tolerance in level.

Which leads me to a serious point – anyone contemplating “Manchester” or “Pendon” wheel profiles and track standards needs to accept that they are forfeiting most of those tolerances, and their workmanship will have to be of a higher order in consequence.  If that’s your bag, splendid, go for it!  Your track will look better than mine.  Personally, and at risk of being considered disloyal to this society, I would wonder why not go the whole hog and choose P4 (maybe with EM profile wheels – Martin Goodall on the Scalefour Forum has done exactly that, and it seems to work well for him.)

Regards,

Bob

[Geoff StennerParticipant]

I had a circular P4 layout in the late 70s-early 80s before changing scale. This was 10′ diameter and the minimum radius was 3’6″ and accommodated small pre-grouping four and six-coupled locos. All worked well.

Having come back to messing about in a very much changed 4mm world forty years later, the reason for considering a souped-up EM standard is that my railway room is only about 2 metres in width, so a tail-chaser layout (which I would like to have after many years of end-to-end working) would have a minimum radius in the 3′ to 3’2″ region, and this time the current impressive RTR locos would outnumber those kit-built ; my experience of the T9 conversion to P4 reveals that everything could be very tight indeed on that degree of curve, so the combination of being able to more easily get down to 3′ radius along with improved appearance of pointwork is what appeals.

I agree that going the whole hog to P4 should be more worthwhile, but I feel any layout I did to those standards under my current circumstance would have to be end-to-end. No besmirching of any of the current 4mm scale track and wheel standards is implied at all; we all have to choose what works best for us.

Geoff

• This reply was modified 1 year ago by Geoff Stenner.

[John CutlerParticipant]

Getting back to the topic of EM-SF…
From a practical point of view, one needs gauges, and not just for the wheels Back-To-Back. An 18mm track gauge should be fairly straightforward to make (I did not say easily!); is one available commercially? The EMGS standard for gauge widening on curves is 0.2mm maximum. This suggests ordinary EM gauges could be used, I recommend especially on turnouts; I tend to add 0.1-0.2mm in ordinary EM and wish there was an 18.4mm track gauge available (0.2mm may seem excessive but allows for the inclination of C&L chairs). The check gauge dimension should be 17.2mm per Martin Wynn; the EMGS standard is 17.25mm although he says the EMGS check gauge can be used (but not available from the EMGS Stores for some time!). Martin refers to a Check Span of 16.4mm which confuses me slightly; I guess that is track gauge minus 2x 0.8mm flangeways?. He further states that gauge widening should not be undertaken in EM-SF turnouts but from practical experience I suggest that is a potential recipe for disaster. I have found a mint gauge (Track Checking Gauge in the EMGS Stores) invaluable for identifying narrow spots in my dodgy trackwork (almost always in turnouts near the blade ends despite putting sets in). If you can get an equivalent one made for EM-SF, I recommend it.
In EM-SF you need to ensure the track gauge is a minimum of 18mm throughout. An EMGS standard wheelset will just (only just) sit with the flange root-radius on the rails . This means that any reduction in gauge will force the wheels to rise…. This should not really be a problem, except possibly at turnouts. The advantages are that there should be less sideways movement of stock (I imagine particularly effective for the smooth movement of bogie coach rakes), and improved coupling of AJs through better centreing of vehicles.
If I build a new layout, I might give EM-SF a go if I could get hold of some decent gauges.
On the use of gauges, I agree (!) with Paul. As to whether a sliding fit or an interference fit is best, it depends upon the gauge and its application. For a BTB gauge I tend to use an interference fit as I regard the 16.7mm BTB as a maximum; a standard 16.5mm EMGS gauge gives a sliding fit minimum confirmation. For an 18.2mm track gauge I would require a close sliding fit (as confirmed by a mint gauge).
When setting BTBs you do not want to end up with a BTB that is too narrow. Pulling driving wheels out to correct this can be a real pain. Do not leave the job until later, correct it straightaway. Plastic-centred wheels seem to expand and increase their grip on the axle over time. I find it a disaster to have to dismantle driving wheels after the initial fixing. Invariably remounted wheels give wobbly or looseness or quartering problems; I now always automatically replace such wheels with new ones.

• This reply was modified 11 months, 3 weeks ago by John Cutler. Reason: corrects mistype of measurement

[Paul WillisParticipant]

On Bob Allison said
Hi Paul,

Good to hear from you again; after your post on 3rd July I feared that you might have abandoned this forum altogether.

Firstly, in fairness to you and the P4 chappies (I was one for 30 years and am still a member) I have never heard any of them claim to get anything right to a hundredth of a millimeter.  18.83 is a nominal dimension.

That said, I think most if not all would agree that the official EMGS standards are more forgiving of errors than P4.  Take back-to-back for instance: with accurately laid track and tyre profile as per official drawing, the back to back can vary between 16.25 and 16.65 without derailment (albeit with slightly rough running at the extremes).  Of course, the track will never be perfect, so this 0.4mm tolerance might better be viewed as being shared between track and wheels.  Also, EM flanges are nearly twice as deep as P4 flanges, so there is more tolerance in level.

Which leads me to a serious point – anyone contemplating “Manchester” or “Pendon” wheel profiles and track standards needs to accept that they are forfeiting most of those tolerances, and their workmanship will have to be of a higher order in consequence.  If that’s your bag, splendid, go for it!  Your track will look better than mine.  Personally, and at risk of being considered disloyal to this society, I would wonder why not go the whole hog and choose P4 (maybe with EM profile wheels – Martin Goodall on the Scalefour Forum has done exactly that, and it seems to work well for him.)

Regards,

Bob
Morning Bob,

I haven’t abandoned the EMGS forum.  Although the sheer user-unfriendliness of the experience means that I visit it less.  And I certainly aren’t going to bother trying to make long posts with pictures again. It’s just too frustrating to do.

Although in the spirit of trying, here is one of the pictures that I was going to post to that thread.  It’s of an EM wheelset on some EM gauge track built with 2mm rivets:

Anyway, I just wanted to say that I completely agree with you – no matter whether it is EM-SF, or P4 or whatever, it is always a trade-off between the visual appearance and the ease of construction and use.  I’ve always been happy with P4, but moving to the finer tolerances of S4 (a la Ray Hammond and a couple of others) has always scared the life out of me.

You mention Martin Goodall’s approach of EM wheels on P4 track.  Of course, that is “EM-fine” wheels like Gibsons or Ultrascales.  You would never get a Markits wheel profile or a pulled out OO RTR wheel through P4 flangeways.  But it does make a lot of sense if you’re not a hair-shirted purist.  The track, which is always on view, is to prototypical standards and looks better, whereas the wheel flanges that appear only when rolling stock is present, and are generally hidden under some gubbins, are less noticeable as to being overscale.  It makes sense to me, even if it is not the path I chose many years ago.

I’ll keep an eye on what is happening over here occasionally, even if the forum does tend to log me out when I’m not looking.  And I’ll stick a post over in the Coffee Lounge in a moment…

Take care,

Paul

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