Society Gauge Widening Tool

Discuss the prototype and how to model it.
Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Sat Apr 23, 2016 5:03 am

Alan
Your editing of your graph now shows the 54mm length to behave as I expected. It is really instructive. People could argue the toss as to which of those lines, green or black, is closer to the function of the real thing, as the black one coincides exactly for 5.5 chains, which is all that I had claimed for it.

Surely what your graph begs is another line showing what the 29.75 length of the Society rectangular gauge does? That would put this whole thread into visual terms.

I would be very grateful if you could do that.

Julian

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Paul Townsend
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Re: Society Gauge Widening Tool

Postby Paul Townsend » Sat Apr 23, 2016 5:53 pm

Julian Roberts wrote:
I don't want to sound like Frankie Howerd, still less like my namesake Mr Clary (!), but this question is exactly the point of this thread, if the Mint gauge is used for anything other than straight track. Not to get personal Paul (Townsend), how long is yours, and do you use it just on straight track on "Highbridge"?



My Standard Gauge Mint is 35mm long and around 10 years old.

I have an early BG one of same length an one of the new production BG ones at 40mm.

I do use them on plain track curves down to 4ft radius frequently and occasionally to 3' 6".
They are also helpful on straight crossings and to sort bumps at rail and baseboard joints

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Sun Apr 24, 2016 9:56 am

Thanks Paul. As you said,
I have used it for years as a diagnostic tool rather than a construction aid. For this it is quick and easy to find undergauge areas of track

The fact that it is 5mm longer than the Society Gauges has not brought any problems I take it...

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Sun Apr 24, 2016 3:29 pm

Will

Thanks for your reply a couple of days ago.

Alan's graph (April 22nd) shows that a track gauge 45mm long (whether triangular, rectangular, or 'Mint'), 50% longer than the Society gauges, is the length needed to give minimum prototypical widening. The 54mm I had suggested I now see is a maximum.

Although he says it is a simple calculation, I have not the skills needed to fill in the graph to show how far away our 29.75mm gauges are from his minimum.

Regarding what you said,
One of the objectives of the P4 standards is to have a consistent set which ensures that locos built to P4 standard will run satisfactorily on P4 layouts.
And
While I would admit to coming from the "getting at all right"tendency and thus suspension free vehicles and over size flanges are not my thing


please can I assure you that I am in exactly the same boat as you are. But, if you don't mind bearing with me, it seems to me that there is not a very consistent P4 approach on gauge widening, except the standard of 0.22mm maximum. Nor is there official endorsement of the gauge widening tool. If you look at the Scalefour Digest 1.2 Track and Wheel Standards, it has below the table of standards, and note the asterisk:
* These dimensions are controlled by construction gauges.

The asterisk, which appears by the track, check, and crossing flangeway dimensions, is absent from the gauge widening dimension. Somewhere on this Forum Russ Elliott says about the gauge widening tool something along the lines of, "the accuracy of the use of these artefacts cannot be verified"

Edit: I am misquoting Russ here. He says:

and ultimately it depends on the inherent accuracy of a check gauge, which is unknown since the accuracy of those artefacts is impossible to validate.


See his post on May 5 2012 at

viewtopic.php?f=5&t=2021&hilit=gauge+widening+through+the+crossing

End of edit.


I have only recently gone into track making and was perplexed (meaning confused) about different approaches to gauge widening, as not everyone uses the triangular gauge. Looking at the website, it looks as though there have been some changes over the years on the issue. If you look at the Protofour Manual "Gauges for Tracks and Wheels" at

http://www.scalefour.org/history/p4gauges.html

you can see that the triangular track gauge (that in this conversation everyone is taking for granted as being the way to make curves), was called the Mark 1 track gauge, but was superceded by the "much improved" Mark 2 pattern, the Mark 1 referred to as being "no longer in production". In what sounds rather clunky to me, as though reflecting quite some debate and perhaps a committee form-of-words agreement, there is the statement:

If it is accepted that virtually all curves on a model railway are to radii below the minimum value of the prototype equivalents, it is logical as well as convenient to apply maximum gauge widening in all cases where track is curved. To convert the Track Gauge for use on curved track (Fig. 4), a washer 0.2mm thick is inserted between the spacer and one bush. This is the Gauge Widening factor. It is desirable to maintain two TG and two TG+GW units ready for use when large runs of track are to be made.


A quite different scenario! But how the C&L or Exactoscale Fast Track comes, 18.83mm for straight, or +0.2mm for curved track.

From here on gauge widening is no longer automatic, it is a choice, as although the Manual says

all cases where track is curved.


the question may well be asked, when is a curve just a deviation, and when is it sharp enough to merit gauge widening?

Then one reads the Scalefour Digest 1.2 where it says
Where applied to non-pointwork curves, prototype
gauge widening at 10 chains radius is 0.25in, at 7
chains radius is 0.5in, and at 5½ chains radius is
0.75in maximum. (In 4mm scale, 1 chain is equal to
264mm, or approximately 10½in.) In P4, where
BBmax is less than the 4mm scale equivalent, and
where adequate sideplay can usually be given to
inner axles, gauge widening should not be necessary
unless using long-wheelbase stock around sharp
curves.


- and here it looks as though what has become a question, do I need gauge widening, that should have the default answer, yes, now has the default answer, no.

The question is begged, and not answered, how long is long (wheelbase), and how sharp is sharp (curves)?

After many years of modelling stock, mostly locomotives, nearly 10 years in P4, I don't take anything on trust. My first effort at compensation and scale wheels, admittedly in 00, resulted in a loco more prone to derailment than before, and for my first chassis in P4 I used the P4 spacers made by the same manufacturer and ended up with not enough sideplay. I realized the need to understand what is going on in order to fix the problems, preferably before starting.

To me as a fairly seasoned Scalefour Society member, starting to make some track, I look around for instructions, and those two Protofour approaches, and the Scalefour Digest are the three.

One has variable widening, one has the whole lot at once, and the third has none at all.

The only other source of instruction on the website is Keith's article in "Starting in P4" which shows the Mark 1 gauge in use. It would be a lot simpler if this had always been the only method.

It was in this context that I came across Russ's statement that is the opening post of this thread, and this put another layer of questioning into the mix, raising a doubt, confirmed by Alan's graph, over the most promising of the three approaches.

Keith wrote to me near the beginning of this thread

The P4 standard has a slightly reduced back to Back and slightly wider flangeways than an exact reduction from the prototype (hence leaving room for the really keen to 'correct' this). This is intended to give a little more tolerance in construction and has the effect of reducing the need for gauge widening.


If we can accurately locate the wheels as per the Scalefour standard, they are between 17.67 and 17.75 apart. The prototype “window” is between 17.87 and 17.89. Thus while our wheels may be as much as 0.22 narrower, they may be set only 0.12 narrower than the prototype. Quite close to the wind as the prototype widening gets to 0.2mm if we put in only 0.1mm?

Paul Townsend's reply regarding his use of the 35mm Mint Gauge shows that his P4 world does not implode nor do his trains fall inside the tracks. Alan Turner's 45mm length gauge would have a minimum usable radius of about 3 foot 3 inches before going outside the prototype 0.25mm maximum, or around 3 foot 11 inches to stay within the 0.22mm P4 standard.

Will,
I rather think that a desire to be pedantic about the prototypical use of gauge widening

I am not trying to be pedantic, sorry if it comes over like that. Like you, I am of the "getting it all right" fraternity. Rather, my gist is that surely we are asking for trouble giving ourselves less leeway or extra room on curves than the prototype, and this might partly explain P4's reputation in some quarters as not being reliable. We might find it easier to get reliable running if we took more heed of the prototype surely?

But the main point of all this is to provoke debate and learn something: most people did not know the Society gauge only gives around half the amount of gauge widening (more exact figures hopefully will emerge from somewhere): and no one has come up with a reason that the P4 maximum gauge widening is 0.22mm rather than the prototype maximum of 0.25mm, though obviously the difference is simply a mathematical rather than practical one.
Last edited by Julian Roberts on Wed Apr 27, 2016 7:56 pm, edited 1 time in total.

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grovenor-2685
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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Sun Apr 24, 2016 4:23 pm

It would be a lot simpler if this had always been the only method.

Its always worked for me!
"much improved" for the Mk2 gauges, IMHO just meant cheaper to manufacture, I have a set and occasionally use them when I want to hold rails temporarily and both my Mk1 gauges are in use. I have never used the gauge widening washer.
I see no reason why using a fixed amount of GW for curved track will not work perfectly well however, and clearly with fasttrack bases economics prevents any other option.

If you are using a track construction method that allows it, then I recommend sticking with the triangular gauge.

But given you have already made quite a bit of stock, what have you used to check it for adequate sideplay etc. you now need to build track that matches your test conditions.
Regards
Last edited by grovenor-2685 on Sun Apr 24, 2016 9:52 pm, edited 1 time in total.
Reason: Quote corrected

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Sun Apr 24, 2016 5:37 pm

Hi Keith

All my stock is for my local West Scotland Group till I have time, after retirement probably, to make a layout if I get the urge. There is a versine calculation that I don't know where came from that I use.
CALCULATING SIDEPLAY (versine).gif
CALCULATING SIDEPLAY (versine).gif (1.63 KiB) Viewed 4003 times

and I take 4 feet as my minimum radius. Half a mm each way has been more than adequate so far, but that has meant using EM spacers (after the first loco in P4), until my latest build, a Hi Level Barclay Tank where Chris' P4 spacers give more than enough side play for this radius.

Be assured I am using the normal triangular gauge for my track making venture which is also for the club.

So you don't think that the Protofour migration from the triangular gauge was to do with a change of idea about how well it worked?

I can see from that graph the logic of the triangular gauge that we have, as it can probably be used down to a very minimal radius without going outside the 0.22mm widening. Personally I am not interested in less than prototypical curves, at least "on stage", so a minimum radius that a 45mm gauge would give, around my 4 feet that I arbitrarily chose for my stock, would be more than adequate. For that day in the future when time permits.

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Sun Apr 24, 2016 6:11 pm

Actually that versine thing might be a load of b*****S. It is in my files, but thinking back I may have found it useless, not sure...1mm total narrowing of frames has done the job so far, so half mm each way.

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grovenor-2685
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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Sun Apr 24, 2016 9:56 pm

So you don't think that the Protofour migration from the triangular gauge was to do with a change of idea about how well it worked?

No! Of course those who made those decisions are no longer with us so we only have the memories and the archive.
Regards

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Paul Townsend
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Re: Society Gauge Widening Tool

Postby Paul Townsend » Mon Apr 25, 2016 6:56 am

grovenor-2685 wrote:
So you don't think that the Protofour migration from the triangular gauge was to do with a change of idea about how well it worked?

No! Of course those who made those decisions are no longer with us so we only have the memories and the archive.
Regards


IMHO the only problem with the triangular gauge (designed for Brooke-Smith soldered rivets) occurs when used with C&L/Exactosale functional chairs for bullhead rail. These provide rail cant and the triangular gauge had long legs that fought this; it is easy to shorten the legs with a file or mill. I only shorten the outer leg so it just fits the rail head depth.

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grovenor-2685
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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Mon Apr 25, 2016 7:49 am

I heard this long leg story before, but both my gauges came with short legs, must have been a rogue batch at some stage, or was it an "improvement".
Regards

Alan Turner
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Re: Society Gauge Widening Tool

Postby Alan Turner » Mon Apr 25, 2016 8:20 am

Julian Roberts wrote:Alan
Your editing of your graph now shows the 54mm length to behave as I expected. It is really instructive. People could argue the toss as to which of those lines, green or black, is closer to the function of the real thing, as the black one coincides exactly for 5.5 chains, which is all that I had claimed for it.

Surely what your graph begs is another line showing what the 29.75 length of the Society rectangular gauge does? That would put this whole thread into visual terms.

I would be very grateful if you could do that.

Julian


As requested:

Gauge Mint 4.png
Gauge Mint 4.png (19.76 KiB) Viewed 3912 times


regards

Alan

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Tue Apr 26, 2016 7:37 am

Alan

Many thanks. Feel free to ignore any further requests from me. I wonder how you produce these things. Anyway, I have realised that your understanding of the prototype gauge widening steps, resulting in the 45mm gauge curve you drew previously, is much more appropriate, and that my taking the maximum gauge widening at 5.5 chains was not understanding the issues properly.

So I wonder if you could do a mix of the last two graphs, showing the 45mm gauge, and the 29.75mm gauge?

I think that would be the instructive contrast. Thanks in advance if that is possible...

Alan Turner
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Re: Society Gauge Widening Tool

Postby Alan Turner » Tue Apr 26, 2016 8:50 am

Julian Roberts wrote:Alan

Many thanks. Feel free to ignore any further requests from me. I wonder how you produce these things. Anyway, I have realised that your understanding of the prototype gauge widening steps, resulting in the 45mm gauge curve you drew previously, is much more appropriate, and that my taking the maximum gauge widening at 5.5 chains was not understanding the issues properly.

So I wonder if you could do a mix of the last two graphs, showing the 45mm gauge, and the 29.75mm gauge?

I think that would be the instructive contrast. Thanks in advance if that is possible...


I think this gives you all.

Gauge Mint 5.png
Gauge Mint 5.png (60.33 KiB) Viewed 3818 times


regards

Alan

essdee
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Re: Society Gauge Widening Tool

Postby essdee » Tue Apr 26, 2016 9:16 am

Now, that's what I call good service!

Well done Alan,

Best wishes

Steve (not yet at the stage of applying this - but very useful knowledge to have to hand).

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Re: Society Gauge Widening Tool

Postby FCA » Tue Apr 26, 2016 9:16 am

Paul Townsend wrote:
IMHO the only problem with the triangular gauge (designed for Brooke-Smith soldered rivets) occurs when used with C&L/Exactosale functional chairs for bullhead rail. These provide rail cant and the triangular gauge had long legs that fought this; it is easy to shorten the legs with a file or mill. I only shorten the outer leg so it just fits the rail head depth.


It has always been my understanding that the triangular gauge was indeed machined to reproduce the prototypical 3 degree cant. However, I cannot find any evidence to support this assertion. Digest 23.2 describes the "new" (1978) track gauge and states that it can be used to create cant. Unfortunately it doesn't say how.

Richard

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Tue Apr 26, 2016 12:28 pm

Too much information overload can be wonderful!

Thanks Alan. May be back for more.... :thumb

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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Tue Apr 26, 2016 6:12 pm

It has always been my understanding that the triangular gauge was indeed machined to reproduce the prototypical 3 degree cant

Not the ones I have, which are early versions. An extra gadget would be needed to hold the rail accurately at 1:20.
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Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Wed Apr 27, 2016 7:59 am

Alan

Terribly slow of me. Your original 45mm curve was mint flavour. :D Now in the tutti frutti concoction it is boysenberry/blackberry/blueberry flavour. :P

Which flavour do you think is the best. I still like the 45mm curve, whichever flavour it is. Presumably you think that most closely approximates the real thing, as that was the one you came up with.

I wonder if you have some numbers.

You see where the boysenberry line crosses the red line at approx 1000mm and approx 1450mm?

Can you tell me what the numbers are in the left hand column for the bottom of the class spearmint flavour 29.75mm at the same points? They will be approximately 0.08 and 0.11.

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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Wed Apr 27, 2016 9:06 am

Which flavour do you think is the best. I still like the 45mm curve, whichever flavour it is. Presumably you think that most closely approximates the real thing, as that was the one you came up with.

Best for what?
IMHO, if you are using the P4 standards, then stick to them and use the triangular or rectangular gauge of 29.75mm length, this has been proven to work over almost 50 years.
If you are using exact scale dimensions (aka S4) then use exact scale gauge widening as well since your use of exact scale Back to back will have removed the additional tolerances allowed in the P4 standards.
Regards

Alan Turner
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Re: Society Gauge Widening Tool

Postby Alan Turner » Wed Apr 27, 2016 3:34 pm

Julian Roberts wrote:Which flavour do you think is the best. I still like the 45mm curve, whichever flavour it is. Presumably you think that most closely approximates the real thing, as that was the one you came up with.

.


I don't think any flavour is best. As I originally said I find the concept of the "Mint" gauge bizarre and I have no intention of using one. The purpose of the graphs, I had hoped, was to show what a nonsense such a gauge is to use on P4 track work.

regards

Alan

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Paul Townsend
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Re: Society Gauge Widening Tool

Postby Paul Townsend » Wed Apr 27, 2016 5:00 pm

Alan Turner wrote:
Julian Roberts wrote:Which flavour do you think is the best. I still like the 45mm curve, whichever flavour it is. Presumably you think that most closely approximates the real thing, as that was the one you came up with.

.


I don't think any flavour is best. As I originally said I find the concept of the "Mint" gauge bizarre and I have no intention of using one. The purpose of the graphs, I had hoped, was to show what a nonsense such a gauge is to use on P4 track work.

regards

Alan


I am not knocking your analysis, as an engineer I appreciate this sort of theoretical approach, but as you are against the mint please design a gadget that does what many of us use the mint for and satisfies your analysis too.
The world will beat a path to your door.

John Palmer
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Re: Society Gauge Widening Tool

Postby John Palmer » Wed Apr 27, 2016 6:25 pm

Encouraged to do so by favourable comments made about the mint gauge on this forum, I acquired one at Scalefour North, but am now somewhat disheartened by Alan Turner’s round condemnation of the gauge.

If I have correctly followed the underlying purpose of Alan’s original graph, he set out to show that a mint gauge capable of gauging the 4mm equivalent of 0.75” maximum GW would need to be 54mm long, but that such a gauge would yield excessive GW in all other cases.

I don’t doubt that this is so, but surely the graphic proof of such an argument is somewhat academic since there has been no proposal to produce a mint gauge that is 54mm in length, the only such gauges so far actually produced being either 35mm or 40mm in length (my new one is 40mm long – I’m neither bragging nor complaining).

My triangular Studiolith gauge is 31.40mm between outer faces of the wide spread claws, and my Society oblong gauge is 30.25mm long (knew those nice new vernier callipers would come in handy…). Presumably they fit somewhere between the 29.75mm and 35mm plots on Alan’s latest graph, and as such correctly produce something close to the equivalent of 0.25” GW on a curve of approximately 1800mm, but otherwise produce GW falling appreciably short of the prototype equivalent.

If I have correctly interpreted Alan’s graph then I assume that the ‘old’, 35mm mint gauges provide a rather better ‘fit’ to prototype GW equivalents than the Studiolith and Society gauges mentioned, and that the newer, 40mm mint gauge provides an even better GW ‘fit’ save for curves in the range of radii between 1800mm and 2400mm. Could such a perception have accounted for the increase in the mint gauge's length?

Or have I completely misunderstood what Alan is seeking to demonstrate, in which case is he suggesting that the whole concept of gauge widening by means of gauge triangulation is fundamentally flawed?

I take Keith’s point that the less-than-scale-equivalent permitted BB range may have reduced the need for GW somewhat. However, it strikes me that that this can only be so for a wheelset mounted true upon its axle provided its EF matches the scale equivalent of the prototype’s EF. Is that right?

In any case, if you plan to construct checkrailed track with functional chairs, the only GW factor made available by the Exactoscale check chairs appears to be 0.12 mm, which has always struck me as being a bit ‘betwixt and between’ the 0.08333mm and 0.1666mmm values required to represent, respectively, 0.25” and 0.5” GW on the prototype.

Julian Roberts
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Re: Society Gauge Widening Tool

Postby Julian Roberts » Wed Apr 27, 2016 7:33 pm

grovenor-2685 wrote:
So you don't think that the Protofour migration from the triangular gauge was to do with a change of idea about how well it worked?

No! Of course those who made those decisions are no longer with us so we only have the memories and the archive.
Regards


Keith - can one read the archive? Is it on the Society website?

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?

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grovenor-2685
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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Wed Apr 27, 2016 8:54 pm

Keith - can one read the archive? Is it on the Society website?

See http://www.scalefour.org/history/history.html
and http://www.scalefour.org/members/protofoursociety/
Regards

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Re: Society Gauge Widening Tool

Postby grovenor-2685 » Wed Apr 27, 2016 10:05 pm

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
(45.96 KiB) Downloaded 73 times

Regards


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