NEM Coupler Pocket Discrepancies On OO Gauge Models

[gazmanjack]

Why is it that there are the NMRA/NEM standards for model manufacturers to go by, that each manufacturer quite often can not get the height of the NEM coupler pockets correct ??

 

Unfortunately this also happens within their (individual manufacturers) own range of models. Not to mention the amount of 'slop' or 'droop' in in the NEM coupler pockets.

 

Here is a classic example of a Dapol Class 22 and a Dapol Pressflow both fitted with Kadee no.18, showing off the height discrepancy and the amount of droop on the Class 22...

 

 

Surely you would think that it couldn't be too hard for the manufacturers to work off a standard that has been around for quite some time now. How many other modellers have come across this PITA and how do you go about rectifying this common problem ??

 

Discuss.

 

Cheers, Gary.

 

 

 

 

 

 

[Butler Henderson]

The Kadee on the loco looks to suffering from NEM droop - is there enough vertical play in the socket to slip a strip of metal below the bottom of the coupling which may raise it sufficiently

[westerner]

It does seem to be a common problem, with coupling heights varying between all the major manufacturers. as well as NEM droop.

[Pacific231G]

It's not just a problem with 00 models. I have seen a lot of variation with European H0 models where the MOROP standard has been around for far longer so there's even less excuse. Sometimes this is down to droop but with others it seems the manufacturers just can't be bothered to get it right. Some of them are so far out that even NEM "dunny seat" couplers won't work. 

 

NEM362 gives a tolerance of -0.05mm for the depth of the box and ± 0.2 mm for the height of its upper inside face from rail height. If that was followed everything would be fine and dandy. I modelled American H0 in the mid 1970s and simply don't remember anything like the same departures from  the NMRA norms for coupler pockets (nor come to that with RP25 wheelsets). Even with the cheapest shake-the-box kits, apart from sometimes having to clean up a bit of moulding flash, you simply fitted the  Kadee no 5s, clipped the cover on the pocket and put the car on the layout. I don't think I even owned a pair of Kadee pin pliars and, apart from a few crafstsman kits where you had to fit your own coupler mounts, mostly used the height gauge for setting up the uncoupling magnets. 

What makes this doubly annoying is that Kadee churn their NEM couplers out by the gadzillion and seem to have no problem achieving complete consistency. I suspect that in the US market manufacturers simply couldn't get away with not sticking to NMRA norms.  Maybe that's why modellers there are so much keener on actually operating their layouts rather than just running trains.

 

I have generally found that a sliver or two of paper inserted under the coupler shank  will often cure the problem of loose boxes (a cocktail stick and a certain amount of cursing usually works to get the paper into position) but serious droop is far harder to deal with. For Kadees I've sometimes ended up just using a dab of superglue to fix the box to the underside of the buffer beam and sacrifice close coupling but in 1:76 scale that probably wouldn't work without something between them. Within fixed or semi-fixed rakes, rigid coupling bars that plug into both boxes may be an answer and several manufacturers produce them.

[34theletterbetweenB&D]

Curing 'the droop', one bodge I have used is to put a wire staple into the vehicle underside to support the bottom of the pocket to keep it at correct height and parallel to the rails while not impeding bogie swing.

 

Further bodges:

Sometimes inverting the pocket is useful for height correction as there is height assymetry in the pocket relative to the mounting.

Sloppy pockets (over spec aperture in height of the opening in the pocket) allow more room for packing to correct drooping.

Cutting out the base of the fishtail mount moulded integral with vehicle undersides allows the NEM pocket to be raised, if the mounting is set low.

 

 

Why the difficulty in reliably conforming to the standard, the manufacturers would have to explain! When the 'fishtail' is used to mount the pocket, I believe they should aim at the maximum height allowed in the standard as an outcome: this compensates for any slight drooping,  and the user can slide the pocket downwards slightly on the 'fishtail' as an adjustment if required.

[roundhouse]

Modelling American outline HO , British outline OO and Czech in HO all fitted with Kadees, the American is by far the most consistent in height although very few items use the NEM box (manily Trix and other European manufacturers Amercian outline)

 

I have had the height issue on both British and European NEM boxes. If the box droops then quite often I use canopy glue to fix it centrally on locos and shorter wagons. I also use canopy glue to hold the NEM coupler within the box  either by turning the item of rolling stock upside down to allow it to set, or packing between track and coupler to get them the correct height. On the Bachmann 4CEP I fitted NEM Kadees instead of the supplied coupling bar (to make it easier to set up in the curved fiddleyard on Star Lane) however the coupling boxes droop severely so I have fixed a loop of brass wired drilled into the underside of the unit that supports the NEM box and still allows it to swing on curves.

The advantage of canopy glue over SUperglue is that it doesn't fog any glazing and also it can be more easily peeled off if the coupler needs replacing.

[D9020 Nimbus]

Another issue can be inserting *any* type of NEM coupling in the box in the first place. On European prototypes—mostly Fleischmann and Roco—I use Kadees and have had no particular height issues, also no problems inserting the coupling in the box.

 

On British prototypes, I just use tension-locks. For those manufacturers which don't fit the couplings in the boxes as supplied, it can be very difficult to even get the (supplied) coupling in the box in the first place—Heljan are a particular problem. Ironically, the only make I've had no issues with is Dapol!

[Astockfan101]

I have NEM droop on my Bachmann class 108 on points it's annoying 

[Grovenor]

Since the NEM standard is for H0 and there is no standard, or standard setting body for 00, its hardly surprising that manufacturers do whatever they feel like.

Keith

[Bernard Lamb]

I have NEM droop on my Bachmann class 108 on points it's annoying 

Try a semi permanent bar type coupling.

I find it helps to reduce the frustration.

Bernard

[Richard Lee]

Since the NEM standard is for H0 and there is no standard, or standard setting body for 00, its hardly surprising that manufacturers do whatever they feel like.

Keith

I don't know whether or not you aware of this:

 

http://www.doubleogauge.com/standards/couplings.htm

[34theletterbetweenB&D]

That's optional, and the manufacturers may or may not observe it as they choose. There is no concerted push from anywhere to obtain conformance in either of universal fitting of coupler pockets, or their correct positioning and function when fitted. Moving on from the coupler pocket, the 'UK standard' coupler is no such thing: a variety of designs of tension lock which sort of work together, but if you put them to the test are not truly reliable in operation with each other despite similarity of appearance

 

This has always been the case for OO RTR in the UK, there simply isn't the drive for standards conformance in the hobby.

 

... it can be very difficult to even get the (supplied) coupling in the box in the first place—Heljan are a particular problem. Ironically, the only make I've had no issues with is Dapol!

I was pleased to find on the Heljan Baby Deltic that there is a solid moulded coupler pocket, rather than the clip together 'looks nothing like a pocket fandangle' that they had employed on the small number of their earlier releases that I own.

[Pacific231G]

That's optional, and the manufacturers may or may not observe it as they choose. There is no concerted push from anywhere to obtain conformance in either of universal fitting of coupler pockets, or their correct positioning and function when fitted. Moving on from the coupler pocket, the 'UK standard' coupler is no such thing: a variety of designs of tension lock which sort of work together, but if you put them to the test are not truly reliable in operation with each other despite similarity of appearance

 

This has always been the case for OO RTR in the UK, there simply isn't the drive for standards conformance in the hobby.

 

NMRA and MOROP standards are also optional. Manufacturers aren't obliged to follow them but, especiallyin the US market, it would be a very foolish manufacturer - or one very confident of its ability to lock its customers into its own proprietary world- that would ignore them. However, if you're going to use a standardised item like the NEM coupler box then it seems crazy to not follow the standard that applies. Unfortunately that's not always the case even amongst European H0 manufacturers.

The specs for the NEM coupler box are the same for H0 and S scale so there's no particular reason not to use it for 00.

[Grovenor]

The specs for the NEM coupler box are the same for H0 and S scale so there's no particular reason not to use it for 00.

Which just makes it even worse for S scale than it is when applied to 4mm scale. I suspect this is because there is negligible following for RTR S scale in Europe.

Regards

Keith

[gazmanjack]

That's optional, and the manufacturers may or may not observe it as they choose. There is no concerted push from anywhere to obtain conformance in either of universal fitting of coupler pockets, or their correct positioning and function when fitted. Moving on from the coupler pocket, the 'UK standard' coupler is no such thing: a variety of designs of tension lock which sort of work together, but if you put them to the test are not truly reliable in operation with each other despite similarity of appearance

 

This has always been the case for OO RTR in the UK, there simply isn't the drive for standards conformance in the hobby.

 

 

 

It does seem quite strange that the UK market for RTR models and the population of modellers in the UK, that there isn't 'drive' for standards conformance. I used to model Australian HO (New South Wales Railway) and the standards down under, conform to the NMRA standards, ie RP25 wheel profiles, coupler height etc. Now in Australia, the ratio of modellers to population is a fraction of the UK, so you would think that the standards would be much more conforming/stringent in the UK market place than the Aussie market place...

 

Maybe the manufacturers needs that 'concerted push' from the end users to get them to recognise their failings within the hobby with dodgy coupling positions. Afterall, we have the standards worldwide for DCC applications and the tools involved ie, decoders...

 

Cheers, Gary.

[Talltim]

In the Uk there has never been a body like the NMRA or NEM, thus there has not been anyone to set the standards. I suspect the reason for the lack is due to the way the hobby has developed here, with many of the type of people interested in getting standards right doing so in, for example, P4

[Talltim]

It does seem quite strange that the UK market for RTR models and the population of modellers in the UK, that there isn't 'drive' for standards conformance. I used to model Australian HO (New South Wales Railway) and the standards down under, conform to the NMRA standards, ie RP25 wheel profiles, coupler height etc. Now in Australia, the ratio of modellers to population is a fraction of the UK, so you would think that the standards would be much more conforming/stringent in the UK market place than the Aussie market place...

 

Maybe the manufacturers needs that 'concerted push' from the end users to get them to recognise their failings within the hobby with dodgy coupling positions. Afterall, we have the standards worldwide for DCC applications and the tools involved ie, decoders...

 

Cheers, Gary.

DCC is an NMRA standard that has been adopted worldwide

[kevinlms]

Since the NEM standard is for H0 and there is no standard, or standard setting body for 00, its hardly surprising that manufacturers do whatever they feel like.

Keith

No, there is much more to it than that. Even within a brand, there appears to be no consistency in their range. It would kind of make sense (not really), if Hornby had one standard & Bachmann another. But why would they want different standards?

[Pacific231G]

Which just makes it even worse for S scale than it is when applied to 4mm scale. I suspect this is because there is negligible following for RTR S scale in Europe.

Regards

Keith

Worse in what sense Keith? It places the couplers beneath the buffer beam which is obviously unprototypical but that's equally true in European H0 and I can't think of anything except three link or practical screw couplings where that doesn't apply. Having a single standard for coupler mounts covering H0 and 00 which is what the Double O gauge Association has done formally by adopting NEM 362 and manufacturers have sort of done has significant advantages. Above all it makes it very simple to use other types of coupler- especially Kadees- and there are plenty of 4mm scale modellers working in both 00 and EM (and P4?) who use those.

 

There is by the way a standard (NEM 370) that specifies the slot in the buffer beam for mounting screw couplings (3 link not having been used in continental Europe for a very long time) allowing some swing for the hook. This obviously is scale dependent and is defined for H0, S, 0, I & II so there must have been some demand for standards for S scale.

[Grovenor]

 

Worse in what sense Keith?

Worse to my railway engineers eye. IMHO couplers sticking out in mid air way below the buffer beam look all wrong, particularly when they are Kadees which otherwise do look as if they belong on a train.

Keith

[Ravenser]

\For whjat it's worth I've got around the problem on Bachmann Mk1s by using the NEM plastic steam pipes supplied. However that was only for the internal coupling in a 2 car set

[gazmanjack]

DCC is an NMRA standard that has been adopted worldwide

 

That is correct. So why can't manufacturers of UK stock have common ground/standards on coupler height with NEM pockets...?? Afterall, without conforming coupler heights, you wouldn't be able to couple a train.

 

You also wrote 'I suspect the reason for the lack is due to the way the hobby has developed here, with many of the type of people interested in getting standards right doing so in, for example, P4'.  Individual groups within the hobby are doing the right thing in regards to standards within their choosen scale/gauge/accuracy, but unfortunately, OO is the introductory level most of us started with. If manufacturers within their own lines of stock cannot get it right, it can't be good for the end user, causing much frustration.

 

Cheers, Gary.

[Pacific231G]

Worse to my railway engineers eye. IMHO couplers sticking out in mid air way below the buffer beam look all wrong, particularly when they are Kadees which otherwise do look as if they belong on a train.

Keith

But don't they do that in H0 as well Keith? Kadees look like real couplers but not at that height and in that position below the drawbar. 

 

I've not got many good examples of Kadees on 4mm scale layouts so apologise for the poor quality of my photos.

They were taken at various exhibitioans and are of  Minories (GN) in EM, Earls Court in 00, and Bradfield in 00.

 

By way of comparison this coupler is on an H0  Bachmann-Lilliput 140C on my small French layout.

Apart from the coupler looking larger on the smaller H0 loco (the lens angle may be accentuating that) I'm not sure if it looks any less wrong than on the 4mm scale stock.

Kadee NEM couplers are cranked so that the botton face of the knuckle is level with the top of the shank that plugs into the box. Other couplers that fit the box including tension lock, NEM hinged loop and Roco close couplers have straight shanks so they sit far lower relative to the buffer beam. This may be a good thing given that they look nothing like any full size coupler but in any case the Kadee NEM coupler is designed  so that the knuckle and the bottom of the trip pin are at the same height as for all other H0 stock corresponding more or less to the standard height of a coupler head in N. America.

If you wanted to establish a specifically 4mm/ft coupler box, presumably a bit higher than the NEM standard for H0, you'd have to persuade Kadee and other manufacturers to produce a range of non-standard couplers designed to work with the coupler head at a different height. I just don't think it's going to happen and for a difference of about 1.5-1.7 mm in the height of the coupler would it be worth it anyway?

 

I believe that some people have found ways of fitting Kadees at drawbar height as "Buckeyes" would be on Mk1 and later coaches and some goods wagons but I think they've removed the pins.

[34theletterbetweenB&D]

...I believe that some people have found ways of fitting Kadees at drawbar height as "Buckeyes" would be on Mk1 and later coaches and some goods wagons but I think they've removed the pins.

 Or even Bachmann, some of whose models of current prototype wagons have a knuckle coupler right in the bufferbeam drag box where they should be. Doesn't conform to any standard! Appearance however is excellent. (Arguably the most accurate RTR wagons on sale anywhere in this respect.) If you straighten the trip pin, track magnet uncoupling capability is available. It proved very easy to put a knuckle coupler on the class 66 at matching height, and bingo, now the airdam and front end detail all fits without interference and the loco is much closer to prototype appearance.

 

I am convinced enough to be moving to Kadee in the bufferbeam of all Pullman gangway coach stock train ends, to get the same improvement. It's not right on any steam or diesel traction for these trains, saving the A4s with a gangwayed corridor tender, but so it goes. Within the trains I stay with the supplied close coupling mechs (CCM) for the appearance improvement this yields on straight and very gently curved track. It would be possible to rework the CCM so it came through the bufferbeam for correct height coupling, I reckon a 36" minimum radius restriction would be required to retain appearance, smaller than this and the buffer stocks have to move! Project for the future.

 

If there were an autocoupler with as much of the appearance of three link and screw link as the Kadee type has to knuckle couplers, to mount in the bufferbeam, I would give that a go too. Come on you mechanically ingenious types, solve the problem. (Closest is the Dingham, near miss in my view.)

[Pacific231G]

 

 

If there were an autocoupler with as much of the appearance of three link and screw link as the Kadee type has to knuckle couplers, to mount in the bufferbeam, I would give that a go too. Come on you mechanically ingenious types, solve the problem. (Closest is the Dingham, near miss in my view.)

Probably the holy grail unfortunately. The Kadee is an automatic coupler based in general principle on a real automatic coupler. 3 link and screw couplings require a very direct human intervention to both couple and uncouple whether in 30.48 mm/ft or 4mm/ft scale.  I blame the UIC for not getting an agreement on a standard automatic coupler across Europe despite a lot of work that was done on that. during the 1950s-1960s .

 

There was a design for an 0 scale autocoupler with an offset drawbar hook mounted in the buffer beam by Jean Rougier in Loco-Revue in July 1953. That had a loop and hook at both ends but the hook was longer than the loop so, unlike the familiar NEM coupler, the loops didn't overlap and it could be used with the buffers doing their job. It was designed for 1:43 scale but comparing it with the Dingham I can't see any reason why it wouldn't work in 00 or H0. The diagram is probably still copyright but I'll PM it to you.