Does anyone produce a NEM pocket "3 link coupling" ?

[phil gollin]

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Does anyone produce a NEM pocket "3 link coupling" ?

 

Obviously it wouldn't be as good as properly fitting a "proper" hook and chain, but simpler.

 

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[HSB]

NEM pockets are mounted far too low for 3-link couplings. The drawgear needs to go in the bufferbeam - not underneath it - or the bottom link would be dragging along the sleepers!

[Andy Hayter]

In theory that obvious failing could be corrected with a stepped hook - like Kadees do for some of their couplings - but frankly I cannot see why you would do that rather than put the coupling where it should be.

[Spitfire2865]

Just cut a hole in the headstock.

It's easier, looks better, and is so much more realistic than the 6 foot long hook sticking out from under the wagon.

[Joseph_Pestell]

I can see the points above. But if you still want to do it, I think that Cav (RBE) of Millers Dale and Burton fame was designing something to be 3D printed.

 

Marklin also used to produce something along these lines.

[Spitfire2865]

Id be interested to see how 3 links could be made to work with NEM pockets. I doubt its effectiveness, but would still like to see the design choices.

[34theletterbetweenB&D]

...If the NEM socket was in the middle of the headstock (i.e. where the hook is on a real wagon) it would be an idea.

In brief, a coupler socket in the headstock to accept any of a drawhook, knuckle coupler, or functional representations of later prototype coupler designs which in reality are mounted in this location. The socket near designs itself and can be implemented with no detriment to continued provision of an NEM specification coupler pocket on the vehicle. A small price increment for the extra tooling per vehicle. Sales opportunity in the supply of alternative couplers to plug in.

[N15class]

Surely if you feel that you need to go to prototypical couplings. You will be prepared for the extra work that's involved. The use of sprung buffers the removal of the toy train curves and points etc. Three link in 4mm works better with EM and P4, in OO there is to much slop in the wheel track ratios and creates more buffer locking, I found that reverse curves had to be of a greater radius in OO than EM because of the wheels and track.

 

You also need to use different size buffer heads as they do on the prototype.

 

Changing three link takes a lot of input from yourself , it is not the sort of thing that cam be done off the shelf.

[Spitfire2865]

Surely if you feel that you need to go to prototypical couplings. You will be prepared for the extra work that's involved. The use of sprung buffers the removal of the toy train curves and points etc. Three link in 4mm works better with EM and P4, in OO there is to much slop in the wheel track ratios and creates more buffer locking, I found that reverse curves had to be of a greater radius in OO than EM because of the wheels and track.

 

You also need to use different size buffer heads as they do on the prototype.

 

Changing three link takes a lot of input from yourself , it is not the sort of thing that cam be done off the shelf.

Please dont start anything about OO Vs EM or P4.

It can work in OO, as with any other gauge. Just always remember gradual curves and points. Trainset curves dont belong anywhere but industry.

Actually, even with OO slop, if you limit curves to 28" radius or so, you shouldnt find much issue. And even that is pretty tight compared to what most modellers prefer. I have a hard time forcing bufferlocking at that radius. If I do get it to lock, the wheels already jumped the rail.

 

And in my experience sprung buffers, while nice on a loco, dont really do much for 4mm wagons. Not enough mass to make much of a difference unless the springs are soft enough to not put up any fight. Though I will applaud anyone who can fit sprung buffers on ALL their stock.

[N15class]

Please dont start anything about OO Vs EM or P4.

It can work in OO, as with any other gauge. Just always remember gradual curves and points. Trainset curves dont belong anywhere but industry.

Actually, even with OO slop, if you limit curves to 28" radius or so, you shouldnt find much issue. And even that is pretty tight compared to what most modellers prefer. I have a hard time forcing bufferlocking at that radius. If I do get it to lock, the wheels already jumped the rail.

 

And in my experience sprung buffers, while nice on a loco, dont really do much for 4mm wagons. Not enough mass to make much of a difference unless the springs are soft enough to not put up any fight. Though I will applaud anyone who can fit sprung buffers on ALL their stock.

It is nothing to do about one being better than the other. but the tolerances are tighter in EM than OO  as they are tighter still in P4. It does make a difference whether people like it or not.

 

As for sprung buffers even with sprung couplings you really need the give in the buffers, unless you use very over scale couplings. All my EM stock was sprung with three link, I used Gibson's springs and heads. Coaches without them did not like curves with out them if run with the heads anywhere near touching.

 

 

The point of my first message anyway was about the need for the converter to put in work rather than finding of the shelf fixes.

[34theletterbetweenB&D]

...The point of my first message anyway was about the need for the converter to put in work rather than finding off the shelf fixes.

 

That's not necessarily true of correctly headstock mounted couplers. Bachmann have been mounting their Kadee clone in the head stocks of OO models of contemporary freight vehicles for roughly a decade. They come out of the box, couple up on the rails and run faultlessly. And also look better in this respect than any other European RTR I have seen; just as North American stock is enhanced by use of a coupler that at least looks somewhat like the prototype device. http://www.Bachmann.co.uk/image_box.php?image=images1/branchline/37-629.jpg&cat_no=37-629&info=0&width=650&height=262

 

So I respectfully suggest that since it has been done, it is quite possible as fully RTR, no user difficulties whatsoever where a suitable coupler design can be used.

 

Screw link and three link: now there's a challenge to arrive at a better looking device to do the job! It's a potentially soluble problem is my view, and should someone devise a suitable device, then the argument for a RTR socket fitting in the headstock gains force.

[Metr0Land]

I don't want to put words in the OP's mouth but I'm wondering if he means 'things that look like 3 link couplings but which fit NEM pockets'

 

ie something akin to the Bachmann hose connectors but which look like 3 links. 

 

If he's not asking then I am!  ie I'd accept they're at the wrong height but when viewed from normal distances look pretty realistic.

[Pacific231G]

I don't want to put words in the OP's mouth but I'm wondering if he means 'things that look like 3 link couplings but which fit NEM pockets'

 

ie something akin to the Bachmann hose connectors but which look like 3 links. 

 

If he's not asking then I am!  ie I'd accept they're at the wrong height but when viewed from normal distances look pretty realistic.

 

I've got a few of these which are rigid coupling bars for NEM boxes moulded to resemble screw link couplers. (loose couplings largely disappeared in continental Europe very many years before they did in Britain)

I'm not very keen on them not so much because of the height being wrong (it would be more wrong in OO) but partly because a tightened screw link wouldn't keep the buffer heads separated like this 

but mostly because, although NEM boxes allow easy interchange of couplings, it does take a certain amount of force and or fiddling with tweezers to do so. This is fine to do occasionally when replacing couplers but, unless the vehicles can be kept semi-pernanently connected, pulling these out every time you need need to put stock away and vice versa does seem to me to risk damaging some detail on the model. 

 

Ironically the reason for positioning couplers beneath the drawbar seems to have been partly to allow the buffer beam and its hook to be kept intact.

[Quarryscapes]

I can see the appeal of having an easy to fit 3 link system but it just isn't going to work with NEM pockets. I'm personally going for long single links to reduce fiddling (or soldered up 3 links). Even on 2'6" minimum radius no springing is required. 

 

I have still to decide how to fit metal drawhooks in place of the moulded ones in RTR locos though, perhaps a similar quandary prompted the OP's question?

[Pacific231G]

 

 

I have still to decide how to fit metal drawhooks in place of the moulded ones in RTR locos though, perhaps a similar quandary prompted the OP's question?

 

I wonder if the slots  might start to appear in RTS models.

Although I've not yet seen a model fitted with them, MOROP have recently updated NEM370  http://www.morop.eu/...s/nem370_f.pdf

that specifies the dimensions of the slot in a buffer beam to fit a coupling hook. it was originally published in 2000 but has been updated this year along with NEM111 (minimum curves) http://www.morop.eu/...es/nem111_f.pdf which now includes a separate table for couplers where the buffers are in contact  which would include screw couplers but also others such as Alex Jacksons.*

There is also an annexe to NEM111   http://www.morop.eu/...nem111an_f.pdf looking at the constraints on prototypical side buffer/screw coupler and how these apply to models which seems pretty well thought through..

NEMs are currently only available in French and German but I'll try to translate the annexe which is interesting. All this seems to indicate a growing interest in continental Europe in using more prototypical couplers. NEM370 only gives the slot dimensions for H0, S, 0, I & II so I suspect there may be more interest in this in the larger scales

 

* Minimum curves to avoid buffer locking and derailments are given in terms of muitliples of the gauge so are scale independent but I think they're assuming NEM standard RTR wheelsets rather than proto. I know that some French modellers use Alex Jacksons but not whether that's true across Europe.

Edited November 30, 2015 by Pacific231G

[Grovenor]

Try this http://www.norgrove.me.uk/GWRtracknotes/R1774A.pdf

Regards

[Pacific231G]

Try this http://www.norgrove.me.uk/GWRtracknotes/R1774A.pdf

Regards

Thanks for this Grovenor, it's fascinating and those formulae could be very useful. Would you happen to know how the GWR worked out the "equivalent" radius for the crossover?

[Grovenor]

Thanks for this Grovenor, it's fascinating and those formulae could be very useful. Would you happen to know how the GWR worked out the "equivalent" radius for the crossover?

Might be in the P-Way notes somewhere, otherwise no.

Regards

[Holmesfeldian]

https://www.shapeways.com/product/8X963ZBED/nem-oo-3-link-couplings-sample-set

 

Chadwick Charlie has experimented with instanters...

 

https://www.youtube.com/watch?v=9o5G5QrGKtM&feature=youtu.be

 

 

[Il Grifone]

In general, Continental screw couplings are longer than British ones as the standard buffer is 60mm rather than the British 1' 8½". They need to be hitched up when not connected, whereas the British ones can be left to dangle.

 

The coupling hooks need to be in the headstocks where they belong.!