Society Gauge Widening Tool

[jim s-w]

When BR started using a slightly narrower gauge did they change thier approach to gauge widening too? As there's no need to worry about large coupled locos with lots of wheels anymore has the approach changed?

[Will L]

Strangely, while I personally find your whole attempt to tie down P4 a "Standard" for gauge widening is misconceived,

It seems to me that defining a generous gauge widening for a layout is a one-shot solution which could do away with model railway-isms like end float on loco axles and clemenson type gadget on six wheeled coaches, but I realise this would go against the masochistic philosophy of most modellers that says they need to spend a heroic amount of time just to get the damn thing to work.

Its an interesting point of view, though I'm not convinced that the heroic amounts of are being spent entirely in this area. Nor has anybody suggested, so far, that they plan to do without axle end floats, where these are typically comparable in size to the amount of gauge widening (hence my suggestion that larger amounts of GW is unnecessary).

Anyway isn't the whole point of modelling P4 that we are prepared to do the work necessary so as not to have to make quite so many compromises, doing otherwise is going against the grain surly?

(hint to self, remember who your talking to)

[Will L]

When BR started using a slightly narrower gauge did they change thier approach to gauge widening too? As there's no need to worry about large coupled locos with lots of wheels anymore has the approach changed?

This thread (oh joy now 10 pages) has already been past this practice on London Transport (under standard gauge on strait track, standard on the corners) although, given the wheel standards remain the same, you can argue the toss as to whether this is gauge narrowing on the strait or gauge widening on the corners).

[jim s-w]

Is that same as what BR did on main lines Will?

[Will L]

Is that same as what BR did on main lines Will?

'Faid I don't know, I'm sure Keith/Martin will though.

[Julian Roberts]

Hi

Yes it's 10 pages long but there's quite a lot of valuable information. Keith put this up earlier.

Also you put in a link to Keith's versine calculation for 6 wheel vehicles earlier.

The gauge widening tool I am suggesting at 44mm would itself incorporate the tiny amount of widening of the track necessary for a 6 wheel vehicle of less length than a short wheelbase 4 wheel wagon to have no end float surely....in other words while I absolutely concur with Bill Bedford's point about saving time and masochism, I reckon we would stilll need end float: but could be more assured against "mystery derailments" caused by minute track irregularities when combined with minute wheel irregularities. It is the combination of errors that causes problems surely as often said and quoted here, by such as Chris Pendlenton.

And one more question. Is there anything optional about the prototype gauge widening at 10 chains, 7 chains, 5.5 chains? Or does it vary in application according to circumstance?

Those figures seem to have been fairly standard in the grouping and early BR era, I would expect pregrouping companies pretty well did there own thing and that may well be hard to find definitive info on.
The attached data I have copied from the Railtrack handbook, the 'New installation' figures relating to the UIC60 rail then recently introduced, I don't know if there have been any changes since.
Gauge_widening.pdf
Regards

[Martin Wynne]

When BR started using a slightly narrower gauge did they change thier approach to gauge widening too? As there's no need to worry about large coupled locos with lots of wheels anymore has the approach changed?

That was only for about 30 years from 1970 to 2000 (1432mm gauge). Since then they have been back to standard gauge (1435mm, 4ft-8.5in). So whatever the approach, it wasn't a success, and no longer applies.

Here is some recent info. (This is almost certainly infringing someone's copyright, if so, apologies.)

rt_gauge_widening.png

Martin.

[Julian Roberts]

Last post of Page 3 for Railtrack GW figures

[Julian Roberts]

As Richard Chown said earlier. 1432 wasn't a success and it would be fascinating and delightfully irrelevant to the thread to know why. He says there that bogie hunting increased.

Martin don't you think that the fact there are now five gradations rather than three lends credence to my idea that the gradations are a practical application of what is a continuum, an averaging out of the wear that would occur without the GW?

[Will L]

That was only for about 30 years from 1970 to 2000 (1432mm gauge). Since then they have been back to standard gauge (1435mm, 4ft-8.5in). So whatever the approach, it wasn't a success, and no longer applies.

Thinking about it, there are still no shortage of 3 axle bogies on the main line railway so some the continuation of Gauge widening is to be expected.

Also there was much successful research went into why bogie hunting occurs and methods of preventing it, particularly at high speed, which must have made gauge reduction, with that intent, redundant.

[Will L]

Reading Ian Rice's article (Wither Hesperus) in Snooze 198, is not just a the enjoyable expedience you would expect, it also illustrates nicely the modelling processes we have traditional used to get our models round sharp corners. I doubt playing with GW will much improve the performance of the loco's Ian built in his prime.

[Julian Roberts]

Hi Will

Could we be having a circular argument???!!!

Richard Chown's piece at

viewtopic.php?f=5&t=4732&start=100

ends that the gauge is now 1435 as Martin says but 1438 for heavy haul. What that implies I dunno.....

[Julian Roberts]

Looking at Martin's latest recent info on GW thinking I think with my dubious maths that the max GW scales down to 0.2mm and the radius from which that applies is a tad less than 5 chains...(?)

Equivalent figures we have used so far are 0.25mm and 5.5 chains.

[Martin Wynne]

Looking at Martin's latest recent info on GW thinking I think with my dubious maths that the max GW scales down to 0.2mm and the radius from which that applies is a tad less than 5 chains...(?)

Equivalent figures we have used so far are 0.25mm and 5.5 chains.

Hi Julian,

Yes, 100 metres is 4.97 chains, scales to 1312mm radius.

Max widening is 16mm, scales to 0.210mm.

That requires a gauge length of 47.0mm:

rt_gw_max.png

regards,

Martin.

[Martin Wynne]

Hi Julian,

Most (all?) of the Network Rail 2010 Track Design Handbook is online here (208 pages):

http://www.networkrail.co.uk/browse%20d ... k_2049.pdf

As far as I know the handbook hasn't been generally available outside the rail industry.

Thanks to David Laing for finding the link.

regards,

Martin.

[Julian Roberts]

Thanx Martin!
Not home yet to play with that calculator but you have done it for me.
Initial thought re 210 pages - ( not looked yet)
Might they be easier to understand than the links Terry put in earlier!??
Only joking...

[Julian Roberts]

Reading Ian Rice's article (Wither Hesperus) in Snooze 198, is not just a the enjoyable expedience you would expect, it also illustrates nicely the modelling processes we have traditional used to get our models round sharp corners. I doubt playing with GW will much improve the performance of the loco's Ian built in his prime.

Note that the version of the standards in Iain's article ("all you needed to know in compact tabular form") is the original 'uninfected' one, with no mention of 528 which I have been arguing is a later corruption of the original "pure" gauge widening standard.

Note that while Iain describes the style as portentious it justifiably could be just that, completely revolutionizing as it does the whole comtemporary ethos. The tragedy is that the almost entirely separate issue of the gauge widening factor (surely?) was not a similar complete revolution and fell back on an existing default option as old as all the other standards that Protofour was created to sweep away, as Martin has established on this thread.

[LesGros]

Some pages back, Julian Roberts wrote:

LesG As this is very easy stuff for you What we need is the right length tool to create 1.6666...mm . gauge widening at 1452mm.
Can you say what that length is? It is just a bit under 45mm.
Can you tell us what gauge widening such a tool will create at 1848 and 2640mm, and at what radius such a tool will create 0.22mm widening

I have refrained from replying to this Challenge(?) because Martin has already replied to this post from Julian.

I infer from this that if the standard is wrong, the triangular tool is the wrong length.

Martin's reply seems to sum up the situation succinctly enough.

Hi Julian,
It's not the wrong length because there isn't a right length, and can't be. Prototype gauge-widening doesn't increase progressively with curvature, it goes up in steps. The prototypical approach is to discard the 3-point gauge and use fixed gauges for 18.83mm, 18.92mm, 19.00mm, 19.08mm, according to the radius:

The thread has highlighted that the triangular gauge works well for ply and rivet, for which it was designed, but if used incorrectly on a curve can cause the track to be under-gauge. Used correctly, it gives a small degree of gauge widening on curves, but if used with moulded chairs, it can again, result in under-gauge track.

Rather than demand a "correct-length-for-gauge-widening tool", would in not make more sense to look for a new design which accommodates inclined moulded chairs? It could be made at a length which creates appropriate widening for (say) 1.1 metre radius which could be a reasonable compromise. Anyone wishing greater verisimilitude could, as now, use individual gauges; in steps, per prototype.

Finally, Ten-plus pages is a nightmare to search for any particular nugget, particularly given the amount of re-posting with over-long-quotes, and not to mention the diversions into EMGS, and 2MGS data.

A plea then: maybe someone [perhaps Julian] might consider creating a short piece (for the Snooze) which summarises, in less than a page of A4, the key points about using gauges to make track.

[Julian Roberts]

Les I have thought the same. I will try to summarize the thread on one side of A4 for here and/or the Snooze.
But the salient points are briefly:
1.It is a question - why does the Society Triangular Gauge give only half the gauge widening on curves that the prototype would use?
2. How long would a gauge be that gave prototypical Gauge Widening
3. Alan Turner explained how gauge widening is a stepped process on the prototype, which a triangular tool cannot replicate. He gave several options presenting them in graph form, showing how little the Society gauge gives, and that a tool giving full widening at 5.5 chains will then give you too much at lower radii.
4. My son produced a simplified graph and all the numbers represented by that graph.
5. I realised that the question needed to be reframed more precisely as 'why does the Standard say 528mm is the radius at which maximum permitted widening occurs.'
6. I asked this question as a riddle in a new topic and FINALLY began to get answers that made sense from Martin Wynne, whose absence from the thread had surprised me.
7. Martin established that the 528 came from BRSMB standards 60+ years old.
8. He established in the early hours of this morning that a 47mm length tool could be both practical and prototypical (I think!)
9. The rest of the thread is taken by very many various misunderstandings, clarifications, perhaps some obfuscation, some resistance to questions being asked, and now denial of the obvious, that the standard needs updating.
10. However, a lot of the thread is taken up by what remains a perennial question, whether the prototype stepped function can ever be adequately replicated by a triangular tool that gives a continuously varying function, and the difficulty of teasing out this issue in the written word.

I will put in to this reply links to take you to the relevant posts

[Julian Roberts]

Les I should have added there but my train from London was just pulling into Glasgow that my friend Allan was kind of and kindly being an advocate for me, and at the same time took the thread into related byways. There have been many interesting questions asked and answered, though there remain some in my mind. (Oh no I hear you saying...).
I must add that people have been very patient and polite with my perhaps persistently irritating questions.

[Julian Roberts]

Several edits to my replies above.

[LesGros]

Julian Roberts wrote:

... I will put in to this reply links to take you to the relevant posts...

Julian,
Rather than post links for each point, It would probably be more helpful if you simply tweak your post to phrase each point as a question, followed by a brief answer, or if more appropriate, a brief clarification drawn from the information from the replies on the thread.
The only links which may be needed could be to the original P4 digest(s), and perhaps to Martin's tables, (which I believe he has published on the Templot companion website).

I agree that the standards document may need an update, primarily to correct the 528 anomaly, but a major re-write is surely OTT?
Perhaps a digest addendum, which addresses issues arising from the use of moulded chairs, would be helpful, and could include the construction of turnouts which combine moulded chairs, and rivets. Sadly, I do not have sufficient hands-on experience to be qualified to write it.

[jim s-w]

Hi Julian

Might I suggest a little preface to your page of A4. What is the problem you are having and how does it present itself?

Followed by a conclusion, what does the improved gauge widenening do to resolve that and what are the practical results?

Cheers

Jim

[Will L]

Hi Will

Could we be having a circular argument???!!!

We may well have been having just that, but I would say (have tried to say several times) that this is because the argument has been conducted in the absence of accurate facts about how best to treat gauge widening in the context of P4 standards. I don't deny it is hard to defend some of the particular figures quoted re gauge widening in the standards, and I understand why the current standard three point gauge may appear to be deficient, but I don’t believe that any of the much quoted items from the archive, which have punctuated this debate, have helped our understanding or quantified the actual mechanisms that require gauge widening.

So I too have a spread sheet. This one seeks to calculate what gauge widening is required to get a vehicle with particular characteristics round curves with a range of radii. Not that I think anybody would want to do that routinely, but because you can use it to illustrate what degree of gauge widening likely to be required.

What I am not going to do is post it all here. I don’t want to hide, what I hope will be at least passingly useful for future reference, at the end of a very long thread which is not attracting many readers (check the ratio of reads to posts).
Follow this link for the next instalment.

[grovenor-2685]

There was another article on this topic in Model Railways for March 1973 which used to be on the site but seems to have been dropped completely. When I get time I'll put it up on my website.

Actually I had forgotten that I had already posted these articles!
Particularly relevant to curving/guage widening are:
http://www.norgrove.me.uk/history_files/mrc3/part-3.htm
and http://www.norgrove.me.uk/history_files ... Mar-73.htm
Click on illustrations for larger versions.
The whole set can be found via http://www.norgrove.me.uk/P4-articles.html
Regards