Auto- Couplings , what choices - decisions

junctionmad
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Auto- Couplings , what choices - decisions

Postby junctionmad » Wed Sep 19, 2018 1:57 pm

Im sure ( I know ) this topic was been debated to death

But I have to make a decision to pick an Auto coupling

The main criteria is it must have delayed uncoupling and be capable of being uncoupled by hidden magnets ( either electro, or servo adjusted permanent magnets )

Ive tested AJs, S&W, Dinghams and Kadees

AJs, I have issues with

S&W, I like the 3mm ones,

Dinghams, I cant get to work on bogie freight and the issue of locos running around stock remains awkward to resolve ( my stock is diesels )

Kadees, well good but wrong " look "

The other issue Id like to resolve is the uncoupling " shuffle " , which tends to occur because the pressure of propelling and typically not relying on the buffers, means that the auto coupler release mechanism ( either a moving loop/hoop or a moving hook ) . is pressed against "a stop ", and wont move under the influence of a magnet

Has anyone derived a delayed action coupling that doesnt require the loco to slightly pull forward to uncouple

My own test with Dinghams, indicates that if I set the hook horizontal position so that the loop drops over the hook , but when propelling , the hoop doesnt touch the back of the hook , before the buffers contact , then no " shuffle " is needed , but that tends to make the coupling very sensitive to radius, and Dinghams are very difficult to handle bogies freight and loco run around


Theres also a moving loop version , I havent tested , rather like a reversed S&W, but I dont think its any different to S&W in reality ( Bougham coupling ???)
Sheesh


dave

Armchair Modeller
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Re: Auto- Couplings , what choices - decisions

Postby Armchair Modeller » Wed Sep 19, 2018 2:07 pm

There is also the Lincs coupler, as another alternative

nec flier.docx
(418.49 KiB) Downloaded 117 times

nigelcliffe
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Re: Auto- Couplings , what choices - decisions

Postby nigelcliffe » Wed Sep 19, 2018 5:26 pm

Another suggestion is "DG", very popular in 2mm circles ("D" and "G" being 2mm modellers). Its available in a variety of sizes, and I know a large EM layout being built using them. On paper, meets the requirements specified.


- Nigel

martin goodall
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Re: Auto- Couplings , what choices - decisions

Postby martin goodall » Wed Sep 19, 2018 8:12 pm

If I may be pardoned for blowing my own trumpet, I shall be demonstrating the 'Burford' auto-coupling at Scaleforum, as part of the Bristol Group's mega-demonstration - you will find us in front of the balcony (turn right from the entrance door as you go in).

I tried out numerous couplings, including Sprat & Winkle, DG, Dingham, etc. etc. but even after modifying them in various ways I could not get the level of reliability out them that I wanted. So I set out to design my own auto-coupling, and (after a long period of gestation) the 'Burford' auto-coupling is the result.

It consists of a fixed hook and a pivoted loop, with an advance uncoupling facility, operated by electro-magnets buried in the track. The coupling is entirely home-made, and is fabricated from wire, which is bent up using two pairs of pliers. Despite its simplicity, I claim something approaching 99.9% reliability in operation, and it is relatively inconspicuous when in use on the layout. (Both the hooks and the loops can be blackened or painted without compromising their smooth operation in any way.)

Etching the loops might speed up production, and is a possibility for future consideration, but once you get the hang of it ,it is relatively straightforward to bend them up from wire.

I shall be happy to show these couplings to anyone who stops at the Bristol Group demo stand during Scaleforum, and there are a lot of other interesting things to see on this demo stand, shown by various members of the group (see the Scaleforum Guide for full details). We look forward to welcoming you to the stand at the weekend.

junctionmad
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Re: Auto- Couplings , what choices - decisions

Postby junctionmad » Wed Sep 19, 2018 8:49 pm

Armchair Modeller wrote:There is also the Lincs coupler, as another alternative

nec flier.docx


does not do delayed uncoupling

junctionmad
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Re: Auto- Couplings , what choices - decisions

Postby junctionmad » Wed Sep 19, 2018 8:49 pm

martin goodall wrote:If I may be pardoned for blowing my own trumpet, I shall be demonstrating the 'Burford' auto-coupling at Scaleforum, as part of the Bristol Group's mega-demonstration - you will find us in front of the balcony (turn right from the entrance door as you go in).

I tried out numerous couplings, including Sprat & Winkle, DG, Dingham, etc. etc. but even after modifying them in various ways I could not get the level of reliability out them that I wanted. So I set out to design my own auto-coupling, and (after a long period of gestation) the 'Burford' auto-coupling is the result.

It consists of a fixed hook and a pivoted loop, with an advance uncoupling facility, operated by electro-magnets buried in the track. The coupling is entirely home-made, and is fabricated from wire, which is bent up using two pairs of pliers. Despite its simplicity, I claim something approaching 99.9% reliability in operation, and it is relatively inconspicuous when in use on the layout. (Both the hooks and the loops can be blackened or painted without compromising their smooth operation in any way.)

Etching the loops might speed up production, and is a possibility for future consideration, but once you get the hang of it ,it is relatively straightforward to bend them up from wire.

I shall be happy to show these couplings to anyone who stops at the Bristol Group demo stand during Scaleforum, and there are a lot of other interesting things to see on this demo stand, shown by various members of the group (see the Scaleforum Guide for full details). We look forward to welcoming you to the stand at the weekend.



Martin, will this coupling release when being propelled without having to draw forward

Dave

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Re: Auto- Couplings , what choices - decisions

Postby martin goodall » Thu Sep 20, 2018 8:26 am

Yes, Dave.

The original version with a fixed over-rider above the hook would only release by backing away slightly (the dreaded 'Sprat & Winkle shuffle'). So I designed the current version with a hinged over-rider above the hook to obviate the need for the shuffle. The coupling is uncoupled immediately the vehicles pass over the magnet (or when standing over an electro-magnet which is then switched on and then off again). The vehicles can then be propelled to the place where the uncoupled vehicle is to be left.

Due to the immediate uncoupling that takes place as the vehicles pass over the magnet, it is not practicable where all the stock is fitted with hinged over-riders to use permanent magnets on the layout, because every vehicle propelled over that magnet would be uncoupled, which is not what is wanted. So electro-magnets need to be judiciously positioned at places where advance uncoupling of a vehicle is required. The appropriate electro-magnet is then switched on as the relevant coupling is about to pass over the magnet, and then switched off again before the next coupling reaches it. It is not necessary to halt the train over the magnet; the movement can be continuous, provided the electro-magnet is switched on at the right moment and then switched off again as the movement continues. Halting over the magnet, and then 'firing' it is another option.

It is easier to demonstrate than to explain; hence the display at Scaleforum. I will publish some notes and illustrations here when I get time to write it up. [There was in fact an older version that I wrote up on this forum several years ago, but the current version is much improved, which has enabled me to simplify the method for bending up the coupling hooks, which in the first version was unnecessarily complex and time consuming. It is now quick and easy.]

See you all at Scaleforum.

junctionmad
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Re: Auto- Couplings , what choices - decisions

Postby junctionmad » Thu Sep 20, 2018 9:10 am

martin goodall wrote:Yes, Dave.

The original version with a fixed over-rider above the hook would only release by backing away slightly (the dreaded 'Sprat & Winkle shuffle'). So I designed the current version with a hinged over-rider above the hook to obviate the need for the shuffle. The coupling is uncoupled immediately the vehicles pass over the magnet (or when standing over an electro-magnet which is then switched on and then off again). The vehicles can then be propelled to the place where the uncoupled vehicle is to be left.

Due to the immediate uncoupling that takes place as the vehicles pass over the magnet, it is not practicable where all the stock is fitted with hinged over-riders to use permanent magnets on the layout, because every vehicle propelled over that magnet would be uncoupled, which is not what is wanted. So electro-magnets need to be judiciously positioned at places where advance uncoupling of a vehicle is required. The appropriate electro-magnet is then switched on as the relevant coupling is about to pass over the magnet, and then switched off again before the next coupling reaches it. It is not necessary to halt the train over the magnet; the movement can be continuous, provided the electro-magnet is switched on at the right moment and then switched off again as the movement continues. Halting over the magnet, and then 'firing' it is another option.

It is easier to demonstrate than to explain; hence the display at Scaleforum. I will publish some notes and illustrations here when I get time to write it up. [There was in fact an older version that I wrote up on this forum several years ago, but the current version is much improved, which has enabled me to simplify the method for bending up the coupling hooks, which in the first version was unnecessarily complex and time consuming. It is now quick and easy.]

See you all at Scaleforum.


Sounds very interesting , last question, can it handle loco run round , ie where two hoops are facing each other

I can’t make scaleforum , as I’m recovering from an operation , so I hope there’s lots of notes , I’d like to build some , a video of it operating would be very useful

Dave

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Re: Auto- Couplings , what choices - decisions

Postby martin goodall » Thu Sep 20, 2018 1:58 pm

Yes, again.

Unfortunately, I forgot to pack a loco with the display when I came away, so I won't be able to show this feature at Scaleforum.

I should make it clear that these couplings are single-ended, with a hook at one end of the vehicle and a loop at the other. This means that vehicles [except locos - see below] must always be kept the same way round on the layout. So this rules out the type of fiddle yard where the whole tray is turned end-for-end.

On the Burford Branch all locos (including tank locos) are liable to be turned on the loco turntable, as they were at Fairford. To cater for this, locos are equipped with both a hook and a loop at each end, but the operation of their couplings is still single-ended, in the sense that it is only the hook or the loop (but not both) that engages with the coupling of the next vehicle.

There is no clash between opposing loops in this case, because the loops are aligned with the buffer heads of the vehicle to which they are attached. So the loops do not meet or overlap. The hooks, on the other hand project 3mm beyond the buffer heads of the vehicle to which they are attached, but here too there is no clash, because the hooks are also offset 3mm to the left of the centre line of the vehicle, and opposing hooks do not therefore make contact with each other. (The hooks are offset to the left because the major curve on my layout is a left-hand curve, when looking at it in the Up direction, i.e. facing towards the fiddle yard, and the hooks are fitted at the Up end of the vehicles, bearing in mind that they are always run that way round on the layout. If the main curve had been right-handed, or if I had put the hooks at the Down end of each vehicle on this layout, I would have offset the hooks to the right.)

There are numerous other details of the design and operation of these couplings that it would take too long to describe here, but I will cover all these points in an illustrated instruction manual, which I will post separately in due course. Most of the detail need not concern a user, but will simply explain the thinking behind the various design decisions, and the reasons for my adopting the dimensions and general arrangement of these couplings as they have now been finalised. In practice, fabrication, assembly and fitting of these couplings is straightforward, and their operation is extremely simple and totally reliable.

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Steve Carter
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Re: Auto- Couplings , what choices - decisions

Postby Steve Carter » Thu Sep 20, 2018 2:38 pm

Thank you Martin.

I’m looking forward to seeing your coupling so expect a visit (when I can get away from the Society Stand of course!).

All the best

Steve
Steve Carter

junctionmad
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Re: Auto- Couplings , what choices - decisions

Postby junctionmad » Thu Sep 20, 2018 3:37 pm

martin goodall wrote:Yes, again.

Unfortunately, I forgot to pack a loco with the display when I came away, so I won't be able to show this feature at Scaleforum.

I should make it clear that these couplings are single-ended, with a hook at one end of the vehicle and a loop at the other. This means that vehicles [except locos - see below] must always be kept the same way round on the layout. So this rules out the type of fiddle yard where the whole tray is turned end-for-end.

On the Burford Branch all locos (including tank locos) are liable to be turned on the loco turntable, as they were at Fairford. To cater for this, locos are equipped with both a hook and a loop at each end, but the operation of their couplings is still single-ended, in the sense that it is only the hook or the loop (but not both) that engages with the coupling of the next vehicle.

There is no clash between opposing loops in this case, because the loops are aligned with the buffer heads of the vehicle to which they are attached. So the loops do not meet or overlap. The hooks, on the other hand project 3mm beyond the buffer heads of the vehicle to which they are attached, but here too there is no clash, because the hooks are also offset 3mm to the left of the centre line of the vehicle, and opposing hooks do not therefore make contact with each other. (The hooks are offset to the left because the major curve on my layout is a left-hand curve, when looking at it in the Up direction, i.e. facing towards the fiddle yard, and the hooks are fitted at the Up end of the vehicles, bearing in mind that they are always run that way round on the layout. If the main curve had been right-handed, or if I had put the hooks at the Down end of each vehicle on this layout, I would have offset the hooks to the right.)

There are numerous other details of the design and operation of these couplings that it would take too long to describe here, but I will cover all these points in an illustrated instruction manual, which I will post separately in due course. Most of the detail need not concern a user, but will simply explain the thinking behind the various design decisions, and the reasons for my adopting the dimensions and general arrangement of these couplings as they have now been finalised. In practice, fabrication, assembly and fitting of these couplings is straightforward, and their operation is extremely simple and totally reliable.


Sounds good to me , I await further info with anticipation

RichardS
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Re: Auto- Couplings , what choices - decisions

Postby RichardS » Thu Sep 20, 2018 9:51 pm

Couplings seem to me to be one of those Cinderella subjects and often an afterthought whereas the coupling adopted can have a big effect on layout planning; especially operation.

Is it possible that, that which, in the UK at least, we seek to replicate is a flawed system in the first place. That is to say with the benefit of 20/20 hindsight would the original railway engineers have adopted hooks, chains, shaped links, and so forth.

Despite the best efforts of many there does not seem to be a satisfactory solution that can provide a good representation of prototype fittings, while being un-obtrusive and delivering automatic features to provide realism.

I do sometimes wonder whether it is wise for a railway modeller to try and design the definitive coupling? Do they have preconceptions about what works, what doesn't work, what things should look like and so forth.

Could it be that the solution lies outside the hobby? Is it time for the hobby to compile a statement of requirements and seek contributions from engineers and designers in other fields who have no preconceptions of the existing range of solutions. Somebody like James Dyson, for example, might see a means to an end.

The only risk I can see is that the outside designers might reinvent the tension lock coupling as the ideal solution. (That, or the Simplex.)

Just a thought.
Kind regards
Richard

I'm not always a railway modelling heretic

junctionmad
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Re: Auto- Couplings , what choices - decisions

Postby junctionmad » Thu Sep 20, 2018 10:13 pm

RichardS wrote:Couplings seem to me to be one of those Cinderella subjects and often an afterthought whereas the coupling adopted can have a big effect on layout planning; especially operation.

Is it possible that, that which, in the UK at least, we seek to replicate is a flawed system in the first place. That is to say with the benefit of 20/20 hindsight would the original railway engineers have adopted hooks, chains, shaped links, and so forth.

Despite the best efforts of many there does not seem to be a satisfactory solution that can provide a good representation of prototype fittings, while being un-obtrusive and delivering automatic features to provide realism.

I do sometimes wonder whether it is wise for a railway modeller to try and design the definitive coupling? Do they have preconceptions about what works, what doesn't work, what things should look like and so forth.

Could it be that the solution lies outside the hobby? Is it time for the hobby to compile a statement of requirements and seek contributions from engineers and designers in other fields who have no preconceptions of the existing range of solutions. Somebody like James Dyson, for example, might see a means to an end.

The only risk I can see is that the outside designers might reinvent the tension lock coupling as the ideal solution. (That, or the Simplex.)

Just a thought.


About the only people that can design it are railway modelers

The reason you don’t have a satisfactory of the shelf solution is because there are simply mutually exclusive requirements

(A) must look like the prototype
(B) simple to fit
(C) small
(D) reliable
(E) support auto uncoupling
( F) support delayed uncoupling
(G) work on small radius curves
(H) work on stock woth bogies and over hangs


In general terms and off the shelf , the Kadee comes close , but of course looks all wrong on period stock

Many of the above attributes are mutually exclusive , the three link coupling was itself not automatic , producing a small unobtrusive coupling that works on model railway curves simply isn’t easy

The problem is we cant get 4mm men with a shunting pole :D

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Le Corbusier
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Re: Auto- Couplings , what choices - decisions

Postby Le Corbusier » Thu Sep 20, 2018 10:50 pm

As a designer of sorts in my day job I would observe that the brief is everything. And I suspect that in modelling as in full size design all is in the end a compromise, and the choice of compromise will vary from person to person. It will never be a one size fits all. So I don't buy the 'Dyson' idea. What we have to remember is that we have a straight jacket that Dyson was never subjected to .. namely a visual prototype that is at the core of everything we do.

For myself, the hand of god and three link couplings are the most prototypical. They look right in use, and they were after all manually uncoupled and coupled on the real thing. Many will totally disagree as the illusion is thoroughly broken by outsize pinkies.

For ease of use and as a spectacle for the viewer an auto coupling/uncoupling is highly desirable. Any auto coupling is always going to look wrong on inspection, so the more discreet the better ... but then of course there will be a trade off between visual discretion and robustness. When all is said and done both Jackson and Spratt & Winkle are pretty well designed and thought out compromises. I am looking forward to seeing Martin's offering to the oeuvre.

The problem from my perspective is that if you want the links to be taut under tension, slack when shunting and to hang loose when uncoupled, you are between a rock and a hard place ... so fingers crossed for good eyesight and a steady hand - not to mention a layout that gives easy access. However such an approach would be totally unsuitable or unworkable on many layouts. :thumb

Fingers crossed for the development of micro engineered 4mm robots with poles :D
Tim Lee

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Re: Auto- Couplings , what choices - decisions

Postby andrewnummelin » Fri Sep 21, 2018 7:52 am

Le Corbusier wrote:...

For myself, the hand of god and three link couplings are the most prototypical. They look right in use, and they were after all manually uncoupled and coupled on the real thing

Fingers crossed for the development of micro engineered 4mm robots with poles :D


Agreed.
However this really isn’t enough. The little robot will also have to tighten screw link couplings (loose coupled coaches look so wrong), connect hoses & cables and even sometimes put the pin in a lug & shakle coupling. Then of course there are the head and tail lamps...
If one goes “modern” image are things any better? Correctly operating gangways are fortunately not something I need to think about for my modelling!
Moving forward in time a bit further, what about things similar to a Scharfenberg (with electrical connections for DCC) and opening noses on an Azuma?
Time to stop dreaming and work on a shopping list for tomorrow!
Regards,

Andrew Nummelin

martin goodall
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Re: Auto- Couplings , what choices - decisions

Postby martin goodall » Fri Sep 21, 2018 6:45 pm

To take up junctionmad's points:

(A) must look like the prototype

This is simply not possible with auto-couplings. The most one can achieve is a coupling that is reasonably inconspicuous. If taken literally, this criterion would allow only 3-link, Instanter and screw-type couplings manipulated by the Great-Hand-in-the-Sky.

(B) simple to fit

Most auto-couplings fulfil this criterion. Some are easier to fit than others.

(C) small

Some are, others not. If using Sprat & Winkle, the 3mm version can be used. I have reduced the size of the hooks of my 'Burford' couplings, as the original version was larger than necessary (due to an excess of caution when originally designing them).

(D) reliable

This was the over-riding criterion that led me to develop the 'Burford' coupling. (Alex Jackson couplings, despite the elegance of their design simply don't perform with the level of reliability that we might reasonably expect.) Other couplings have various reliability issues, and it was in an effort to iron out these problems that I tried first to modify various designs, and then gave up and designed my own.

(E) support auto uncoupling

Auto-couplings are just that - automatic. (That may sound blindingly obvious - but some auto-couplings are more automatic than others!)

( F) support delayed uncoupling

Most auto-couplings do this, some more successfully than others. I hated the 'Sprat & Winkle shuffle', and so re-designed the over-rider on the 'Burford' coupling to eliminate this shuffle. (But I will be demonstrating both versions at Scaleforum.)

(G) work on small radius curves

There are inevitably limits. I have managed to make my 'Burford' couplings work on radii down to 2' 9" radius, but Alex Jackson couplings won't work on radii below 4-ft.

(H) work on stock with bogies and over hangs

This is always a problem, due to the end-throw on bogie stock. My answer to this is to mount the couplings on bogie vehicles horizontally on the bogies of these vehicles, rather than the usual arrangement of mounting them vertically behind the head-stocks.

I shall be happy to discuss all these issues if you visit me on the Bristol Group demonstration stand at Scaleforum.

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Tony W
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Re: Auto- Couplings , what choices - decisions

Postby Tony W » Sat Sep 22, 2018 4:19 am

I'm really sorry I wont be going to Scaleforum this year because the above email by Martin is full of mis information about the Alex Jackson coupling and reads more like a promotional advert for his Burford coupling. Every coupling has its limitations but when you read comments like "Alex Jacksons dont work on radii below 4ft" I really start to question the level of experience encountered with the coupling because I for one, do not experience such problems.
Sorry Martin but I dont understand where you are coming from on this.
Tony

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Re: Auto- Couplings , what choices - decisions

Postby Elventhumbs » Sun Sep 23, 2018 8:19 pm

Given that my forum name is pretty accurate, my short attempt at AJs have not met with success, and I saw Martin Goodall's demonstration plus explanation at Scaleforum today. Impressed, I must say. If I can crack this, then this is one less excuse for not getting on with "The Layout". :idea:

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Guy Rixon
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Re: Auto- Couplings , what choices - decisions

Postby Guy Rixon » Mon Sep 24, 2018 8:35 am

I've never seen a layout exhibited on which AJs were highly reliable during prolonged shunting. The best approach about 95% success rate (that's a fraction of coupling operations, not of stock that behaves well). Most seem to be below 80% and many are below 70%. 5% failures is possibly OK for a home layout but rather disappointing for an exhibit. 30%+ is just terrible!

The AJ design is very clever, but like a lot of clever things does not seem to be truly practical. If I were making them, being very good at messing up moving parts, I'd likely get <70% success rather >=95%. I was going to fit my stock with Dinghams, but I need to turn locos, so I'm going to try Burford couplings. Possibly I will mess these up too, but one must try something.

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Re: Auto- Couplings , what choices - decisions

Postby martin goodall » Mon Sep 24, 2018 9:58 am

I was very encouraged by the interest shown in my demonstration of the 'Burford' coupling at Scaleforum. (I had not anticipated this level of interest, and so I saw much less of the show during the weekend than I had hoped!)

As promised, I will now complete an updated write-up of this coupling, which I will post on this forum in a separate thread with attached .PDF file, but it may take a few weeks to complete this. (It will have diagrams and dimensions, as well as practical instructions on the fabrication, assembly and fitting of these couplings, which are entirely hand-made using simple hand tools - real 'kitchen table' modelling!)

[I should stress that the write-up of an earlier version of this coupling which I posted on this forum some years ago is no longer relevant, as the design has been significantly modified since then, involving a simpler and much smaller hook and the modification of the advance uncoupling mechanism so as to avoid the need for the 'Sprat & Winkle shuffle' which afflicted that earlier version of the coupling.]

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Re: Auto- Couplings , what choices - decisions

Postby martin goodall » Mon Sep 24, 2018 10:10 am

Tony W wrote:......... but when you read comments like "Alex Jacksons dont work on radii below 4ft" I really start to question the level of experience encountered with the coupling because I for one, do not experience such problems. Sorry Martin but I dont understand where you are coming from on this.
Tony


Re Alex Jackson couplings, I was simply quoting from the instructions/advice published by Alex Jackson and his collaborators in Manchester MRS themselves. They made it perfectly clear from the outset that their coupling was not designed to operate on track radii of less than 4 feet. There is no problem in hauling or propelling vehicles that are already coupled round a curve of less than 4-foot radius, but the Alex Jackson coupling was not designed to couple or uncouple on sharper curves than this.

I didn't consider using Alex Jackson couplings on the Burford Branch because my 'ruling' radius was 3 feet (and I then added a siding inside this curve, which has a radius of about 2' 10"). However, I have had plenty of experience of operating a variety of layouts with Alex Jackson couplings, and my experience has confirmed the view expressed by many other people that, despite being a very elegant design, their practical use under exhibition conditions gives a less than satisfactory level of operational reliability.

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Le Corbusier
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Re: Auto- Couplings , what choices - decisions

Postby Le Corbusier » Mon Sep 24, 2018 10:48 am

martin goodall wrote:As promised, I will now complete an updated write-up of this coupling, which I will post on this forum in a separate thread with attached .PDF file, but it may take a few weeks to complete this. (It will have diagrams and dimensions, as well as practical instructions on the fabrication, assembly and fitting of these couplings, which are entirely hand-made using simple hand tools - real 'kitchen table' modelling!)


I shall await this with anticipation, as I failed to get a chance to sit down and discuss the coupling with you in person on Saturday ... the seat was always taken/surrounded .... except at lunch time when quite reasonably you were having a break.
Tim Lee

junctionmad
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Re: Auto- Couplings , what choices - decisions

Postby junctionmad » Mon Sep 24, 2018 5:48 pm

I await the write up with interest

My project is an exhibition layout. And I agree with the general comments around the reliability of the AJ coupling. I found it brilliant when accurately aligned but it’s toofragile for exhibition use

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Tony W
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Re: Auto- Couplings , what choices - decisions

Postby Tony W » Wed Sep 26, 2018 3:15 am

Matin Goodall wrote
Re Alex Jackson couplings, I was simply quoting from the instructions/advice published by Alex Jackson and his collaborators in Manchester MRS themselves. They made it perfectly clear from the outset that their coupling was not designed to operate on track radii of less than 4 feet. There is no problem in hauling or propelling vehicles that are already coupled round a curve of less than 4-foot radius, but the Alex Jackson coupling was not designed to couple or uncouple on sharper curves than this.

Apologies Martin, I’d forgotten about the original MMRS documentation. In later years, and after much research, Norman Whitnall admitted (during his development of the ‘hinged’ version of the coupling) that it was quite capable of being operated at radii of less than 4ft. I should qualify this by saying that Norman would then ask the question, “but why do you want to couple and uncouple on such a sharp curve, they don’t on the prototype equivalent?” I never could argue with Norman when he was in such a logical mood!
junctionmad wrote:
I found it brilliant when accurately aligned but it’s toofragile for exhibition use

Could you please expand on your description, ‘too fragile’. I can understand the comments about people’s troubles with inconsistency, even if I don’t encounter them myself (sorry, I’m not trying to sound smug but I was taught the coupling by the above named gentleman who had probably sorted most problems before most of us were even born) but fragility is not a word I would use to describe a piece of steel wire capable of holding the weight of a human being!!
Tony

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Le Corbusier
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Re: Auto- Couplings , what choices - decisions

Postby Le Corbusier » Wed Sep 26, 2018 5:42 am

Tony W wrote:..... even if I don’t encounter them myself (sorry, I’m not trying to sound smug but I was taught the coupling by the above named gentleman who had probably sorted most problems before most of us were even born)


Ever thought of demonstrating at Scaleforum ;) I for one would love to sit down and watch/have a go :thumb
Tim Lee


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