Couple of coupling problems

[The Johnster]

I'm still having coupling issues with my tension locks.  After the hooks fell out of my Hornby 42xx couplers when I turned it over to attach the brake rigging, I have had 3 break on me in the last week.  Now, I do not drive roughly, as anyone who has read my rantings about this practice will attest, and my loads are risible; 3 coaches or 10 loaded minerals and a toad.  The ones giving the trouble are the type that do not fit into an NEM pocket, but have a holder that that slides upwards into a dovetail housing, and are given the necessary degree of flexibility by a sort of thin pliiable plastic part of the moulding.  It looks weak and clearly is; this is where my breakages are occurring.  I have Bachmann, Hornby, and Oxford stock with them.  They are hopeless; they fall out easily and have to be glued in, in which event they are difficult to replace when (I would have hoped if, but it's when) they break.  Rubbish...

 

This is especially annoying as none of my local outlets are stocking this particular type of coupler at the moment, and all say they are experiencing difficulty in obtaining them.  This of course means that I will also be unable to obtain a supply of spares and have only one left in stock, so the next but one failure will mean that a vehicle has to be taken out of service.  I know I've ranted before about this sort of thing, but it's a typical bog standard British type ^@7% up.  Why can we not have a reliable coupling system that is standard as to fitting and use across all rtr manufacturers for all stock in the 21st century?

 

Suggestion please; not Kaydees as I can't cope with the different numbers, and not scale as my failing eyesight was the reason for reverting to t/ls in the first place, and not any system that requires removal of housings from the vehicles as this will prevent installation of NEM types in future.

[ejstubbs]

I'm having difficulty understanding your description of the couplers.  Are they like this?

 

[Phil Bullock]

Have to agree - think what you have described are couplings fitted in to NEM pockets - tis they that have the wedge mounting

 

Just try pulling the couplings out of the pockets and fitting new ones.

 

Simples!

 

Phil
 

[Theakerr]

But what is causing them to break?  I have used both type in the picture and others and have never had one fail at the dovetail neck.  At least I think that is where the poster is saying they failed.

[The Johnster]

I'm having difficulty understanding your description of the couplers.  Are they like this?

 

 

Those are the fellas, ej, and they break at the narrow part. I think I might be twisting them as I'm uncoupling when I am lifting vehicles and separating them; will be more careful in future.

[The Johnster]

Have to agree - think what you have described are couplings fitted in to NEM pockets - tis they that have the wedge mounting

 

Just try pulling the couplings out of the pockets and fitting new ones.

 

Simples!

 

Phil

 

These are not fitted into pockets, Phil, more's the pity, they slide upwards into a dovetailed housing, as in ejstubbs' photos which show the 'male' pare of the thing. The narrow bit gives them the flexibility they need to cope with reverse curves and such, but is a weak point and breaks easily.  I have mentioned in my reply to ej that I might be twisting them in a way they are not designed for.  They have a tendency to fall out in operation and cause dereilmnets as well, a pain if you are carrying loose coal in your mineral wagons...  If you glue them in, you lose the flexibility.  

 

I am becoming fed up with tension lock couplers!

[DCB]

You must be doing something pretty brutal as our weighted 42XX with a H/D hook grafted to one of these couplings will pull 20 odd Hornby Dublo wagons and with a pilot dragged them up a 1 in 36.  Obviously we don't twist the couplings as the H/D type just lift without twisting.  They fall out on the track of course.  I got fed up with tension locks 50 years ago when I had my first Triang set after starting with Hornby Dublo.

 

I always fancied the N gauge coupler for 00 if I was starting again, but your couplings will keep breaking if you twist the vehicles apart. I suggest you uncouple before lifting them....

[Phil Bullock]

These are not fitted into pockets, Phil, more's the pity, they slide upwards into a dovetailed housing, as in ejstubbs' photos which show the 'male' pare of the thing. The narrow bit gives them the flexibility they need to cope with reverse curves and such, but is a weak point and breaks easily.  I have mentioned in my reply to ej that I might be twisting them in a way they are not designed for.  They have a tendency to fall out in operation and cause dereilmnets as well, a pain if you are carrying loose coal in your mineral wagons...  If you glue them in, you lose the flexibility.  

 

I am becoming fed up with tension lock couplers!

 

 

Cheers - I feel your frustrations! We still have these fitted on all our freight stock and have minor issues as you describe....the odd one has broken at the narrow neck and yes some do drop out - those just get glued in

 

Just to be clear re terminology - the couplings in EJ's pictures consist of two parts - the coupling loop/hook (on the left) and the NEM pocket with the dovetail (on the right)

 

If the pocket falling out problems persist and you want  to retain the ability to swap them then try pockets from a different manufacturer - the dovetails do tend to be slightly different sizes and therefore some can be tighter fits

 

Kind regards

 

Phil

[Il Grifone]

IMHO flexing plastic will fail sooner or later. Yet another reason for not using tension locks!

 

I find the inability to lift a vehicle out of a train a complete PITA, especially following a derailment - these things can cause an entire train to derail with posibly disastrous consequences.

 

A wire loop might be the answer for locomotives - unobtrusive and relatively easy to uncouple. The few locomotives I have with tension locks have almost all had the hook removed. The odd exceptions have the Tri-ang mark II, which isn't a tension lock, but suffers from the same fault of uncoupling problems.

[Dunsignalling]

Those are the fellas, ej, and they break at the narrow part. I think I might be twisting them as I'm uncoupling when I am lifting vehicles and separating them; will be more careful in future.

Repeated twisting will quickly weaken the thin piece that creates the flexing action. The fragility is inevitable, though some are weaker/stronger than others. Indeed, I've had one or two models that arrived with one already half-broken, presumably during assembly.

 

The solution is procedural; use a suitable hand-held uncoupling "paddle" to ensure that vehicles are properly separated before lifting, avoiding any twisting action altogether.

 

These uncoupling tools are cheap and easy to make, I just use a four/five inch length of Plastruct tube (round or square both work) with a suitable off-cut of plastic sheet attached to one end with solvent. A length of tube costing a couple of quid will make at least four. The best size, shape and angle to suit the conditions prevailing on your layout will become apparent as you go along.

 

If uncoupling in a fiddle yard, just fit uncoupling ramps in the "usual places". Home made ones, just a strip of plastic from shirt packaging (the collar/cuff stiffening that is normally thrown away) and a couple of track pins, cost nothing at all.  

 

Also, NEVER lift or support one wagon, even partially, with another: it is very easy to do so without noticing one is doing it. The couplings themselves are usually strong enough to cope but the strain goes straight to the weakest link, the part designed to flex.

 

John

Edited June 14, 2017 by Dunsignalling

[ejstubbs]

These are not fitted into pockets, Phil, more's the pity, they slide upwards into a dovetailed housing, as in ejstubbs' photos which show the 'male' pare of the thing. 

 

As Phil explained, there are two parts to these couplers: the loop & hook bit - the actual tension lock - and the NEM pocket, which attaches to the vehicle using the dovetail and the flexible plastic neck.  They are actually NEM couplings - the NEM specification as defined by MOROP, adopted by the NMRA and recommended by DOGA, doesn't dictate how the pocket attaches to the vehicle, just its size and its location wrt the track and the vehicle buffer beam and buffers.  You can - in theory, at least - use any NEM-compatible coupling in the pocket part of the couplings pictured in my first post.  However, that wouldn't fix the issue of the fragility of the flexible plastic neck.

The narrow bit gives them the flexibility they need to cope with reverse curves and such, but is a weak point and breaks easily.  I have mentioned in my reply to ej that I might be twisting them in a way they are not designed for.

 

I am becoming fed up with tension lock couplers!

 

You would not be the first person to discover that tension locks are decidedly inconvenient if you do a lot of manual rearrangement of stock within trains.

 

One thing that might help could be to look at the Hornby large NEM tension locks R8268:

 

 

They would fit in the NEM pocket in place of the smaller tension locks and you might find them easier to uncouple manually without twisting the dovetailed NEM pocket, because of the larger amount of space inside the tension lock loop.

 

Another answer could be Kadees.  I know you've said that you don't want to go there, but they would have the advantage of not requiring twisting of any kind when manually rearranging trains.  I agree that there is, on the face of it, a bewildering multiplicity of model numbers, but there are in fact only four models of NEM-compatible Kadee couplings - and I doubt you'd find any use for the shortest one on UK stock, so that would take it down to three.  You might do worse than buy a pack of each of those sizes and experiment a bit with them.  (Be aware that if you did switch to Kadees then you'd have to replace any tension lock uncoupling ramps with magnets.)

They have a tendency to fall out in operation and cause dereilmnets as well, a pain if you are carrying loose coal in your mineral wagons...  If you glue them in, you lose the flexibility.

 

I may be misunderstanding what you're saying here, but it should be possible to glue the dovetail into the slot on the chassis without losing the flexibility of the neck.  If you meant "flexibility" in the sense of the ability to change and replace couplings then you can use a strong but non-permanent glue like canopy glue to secure the dovetail but still be able to change it in future if required.

 

I am aware that there are differences between the various manufacturers dovetail arrangements.  The Hornby and Bachmann are subtly different and IIRC the Hornby ones don't always fit well in the Bachmann dovetail slots.  There is no standard for the dovetail fitting, unlike for the NEM pocket itself, so you can't necessarily rely on apparently similar components from different manufacturers working together properly.  It's also worth being aware that the Bachmann ones at least are supposed to be fitted in a certain orientation.  If you look closely at the pocket part of the assembly you will see that one face has a small bump moulded on to it.  That's there to allow the pocket to slide reasonably freely against the underside of the vehicle's chassis.  Install the pocket the wrong way up and it won't swing side-to-side so easily, and will likely sit slightly too high.  Both issues can interfere with reliable running, and with coupling up and uncoupling eg during shunting.

 

Final point: I have a reasonable stock of the Bachmann 36-026 short tension lock couplings, which come with the dovetail/NEM pocket fitting, and I think I have a few Hornby and Dapol ones sculling around.  The Bachmann ones in particular do seem to be available only sporadically.  I have no use for them now, having converted completely to Kadees, so if mine could be useful to you then please feel free to send me a personal message through RMWeb and I can probably let you have them for the cost of the postage.

Edited June 14, 2017 by ejstubbs

[michaelp]

These are not fitted into pockets, Phil, more's the pity, they slide upwards into a dovetailed housing, as in ejstubbs' photos which show the 'male' pare of the thing. The narrow bit gives them the flexibility they need to cope with reverse curves and such, but is a weak point and breaks easily.  I have mentioned in my reply to ej that I might be twisting them in a way they are not designed for.  They have a tendency to fall out in operation and cause dereilmnets as well, a pain if you are carrying loose coal in your mineral wagons...  If you glue them in, you lose the flexibility.  

 

I am becoming fed up with tension lock couplers!

 

Have you considered Sprat and Winkle couplings?  When fitted and painted they are no more obtrusive than tension lock couplings in my opinion.

I am currently replacing all my tension locks with S & W couplings, if you went for the AC3/3 autocouplers they will go round fairly tight curves and have the delay action, you also have the three link chains for magnetic uncoupling and they give a more realistic look to rolling stock.

 

'Vitalspark' of this parish will give you all the info you need if you decided to use them.

 

Michael

[Roger Sunderland]

I have to agree with EJS. Tension lock couplings are the most infernal things, I got rid years ago. If you have NEM pockets on all/most of your stock you only need number 18,19 or 20 Kadees. If you don't have tight curves you only need 18/19.

[34theletterbetweenB&D]

I have to agree with EJS. Tension lock couplings are the most infernal things...

 I feel that needs to be qualified, and can speak as someone who has standardised on a single design of miniature tension lock for freight stock, and gets complete reliability operating full size trains, up to 60 wagons, pulling and propelling. (I expect to be able to perform any move with a train that the real railway performed, those sixty wagons have to be propelled reliably across any point ladder.)

 

The Qualifications:

 

There isn't one standard miniature tension lock coupler. What there are is a shower of lookee-likee designs each unique to a manufacturer, none of which designs are truly compatible with each other if functional reliability is required. (This FACT determined by experiment, and I have very high statistically validated confidence in the result: this required approximately one thousand hours of operation, took me just over a year.)

 

The NEM coupler pocket, though very convenient, was not designed with any thought for installation of UK tension locks of any design, and is actually unsuitable in some respects for this coupler, although these issues may be simply user corrected. (The Airfix/GMR mounting is superior to the NEM coupler pocket, for tension locks...)

 

The mounting and alignment of the miniature tension lock needs to be attended to with the same care specified for the Kadee type, and the standard alters with wheel and track standards. It's fairly easy to achieve and maintain with RP25 wheels on 30" minimum radius in OO, and I haven't gone tighter radius than that.

 

 

 

Conclusion.

Select one design of miniature tension lock, mount it very carefully modifiying the commercially available mounting systems as required, adhere to the tested parameters for the layout trackwork and stock wheels, and you can have them working extremely reliably.

 

 

 

.

[The Johnster]

I thing we are getting somewhere!  Firstly, apologies for the initial rant when my mishandling of the couplings was responsible for the breakages.  I need to be more careful and disciplined in my crane shunting, and have decided to a) immediately, today, build myself another shunting pole, lit and kept at the end of the fiddle yard where it is handy, use it to uncouple stock from locos before crane shunt running around, and not be tempted to uncouple by hand because my shunting pole is up the other end of the layout.  They are not designed to be used in the way I am using them and it is not fair for me to criticise the manufacturers for that,  b) I will investigate the possibility of ramps at the end of the fiddle yard at the positions where the loco come to rest when they run on to the dead sections at the ends of the roads.

 

Secondly. thank you all for your input; i have been given some very good and practical advice.  I am, rants aside, I think pretty committed to tension lock couplers for the foreseeable future.  They have some very good points; I have yet to have a coupling fail in service at the business end, and all my problems have been with the mountings and my initial failure to understand that they have to be the same height above the rail and that this is not the same thing as the same depth below the buffer beam..  Apart from the incidents of dovetail fitting couplings falling out and the trains tripping over them, which can be cured by glueing them in with something that won't stop them being taken out if needed as suggested by ejstubbs, running has been 100% reliable in that no train has divided and I can propel any train anywhere at s reasonable shunting speed of around scale 15mph without it derailing or lock buffering, this over 2' radius Peco pointwork and some no.3 curves in the fiddle yard, which serves as the headshunt for some shunting moves.  I have avoided reverse curves, but one fiddle yard road is accessed through one, a Peco point leading directly through it's curve onto a no.3 in the opposite direction; it a train will propel through this it'll go anywhere on the layout, and they all do except the auto, which that road is built for, which will run or propel though it but the coaches wobble a bit...

 

The prevention of lock buffering in propelling movements is a vital feature on a blt where most of the stock spends as much time being propelled as being hauled.  I agree that the best place for a coupling on a model of a UK prototype is on the buffer beam where it is on the real thing, but this raises the spectre of buffer locking which I am so happy to have disposed of.  I will have a look at Kaydees now I have been told the numbers to buy, perhaps fitting up my mineral rake and 42xx as a trial.  I agree that the large loop t/l Hornbys are pretty forgiving, indeed, the 42xx just mentioned has a pair fitted after the hooks fell out of it's original ones,  I have them on several other vehicles , and they look awful, but they work.  I have issues on some of the curves where a coupling which as a wide t/l like these on one vehicle and a narrower type on the next vehicle pushes the hook of the adjoining vehicle sideways unless I have taken care to ensure that both hooks are over both bars before starting the movement; the obvious inference is that if I am to standardise on a t/l coupler it should be the big Hornby one on my layout.  I have a stock of these and can easily get more locally, but the pockets are a different story.  I cannot claim now that Keydees are either more obtrusive or that I am confused by the numbers; 18, 19, and 20 I can deal with.  Kaydees have a major advantage in that I will be able to lift vehicles straight upwards out of the middle of rakes with minimum disturbance to their neighbours, and put them back with equal facility!  I am assuming that types are available which fit both the NEM pocket and the dovetail.

 

I have some experience of Spratt and Winkle back in the day, and was not that impressed.  They were much touted 30 odd years ago as the best possible compromise between operation and appearance, but my view was and still is that they are merely an admittedly finer t/l upside down and are fiddly and time consuming to install; moreover, IIRC, the plastic mountings on rtr vehicles originally supplied with t/ls of any sort has to be removed to install S & W fixing plates, which require a clear flat surface on the underside of the vehicle's body.  I am not happy about such drastic and irreversible surgery on my stock.  I have had to build my own mounts for couplers on vehicles which have survived from the old days and were fitted with 'scale' instanter or screw couplers, a faff and fiddle that I do not wish to inflict upon myself with my more modern stock.  These bodged couplings are still in service, but work despite themselves and I intend, over time, to replace them or at least their chassis' with modern types including the NEM pocket or dovetail.

 

I uncouple with a coupling pole which has a wire hook on the end to lift the hooks over the bars.  i tried a spade type, but could not use it in all locations due to the need to approach the problem from the side with platforms or other structures in the way. (it is a principle of mine that any vehicle should be capable of being coupled, which is the greatest advantage of t/ls and uncoupled anywhere on the layout; my shunters walk up and down quite a bit, and do not wait for the wagons to come to them), and found that, because of  the variety of couplings and fixings even amongst my massive fleet of 36 vehicles means that the bottoms of the droppers are at different heights above the rail and that there are differences in the clearance available between vehicles, sometimes even in the space between the buffers, which made it difficult to design a spade which will cope easily in all circumstances, but I may well reconsider this if the Kaydee trials are not satisfactory.  Standardisation would be highly desirable, but there are too many different situations, bogies, long or short wheelbase vehicles, different overhangs especially on auto trailers, to be able to accomplish this.  34C's comments are highly germane, but I have to live with 24" radius points and no.3 (20"?) curves, and am nowhere near being able to standardise of wheel profiles as I have an eclectic mix of rtr from different colour boxes, and kit built, stock.  Fine scale modeller I am not...

 

Thank you all again for your kind advice and efforts on my behalf.  It will be some time before I am able to get around to fitting some trial Kaydees, but I will report back when I do!

Edited June 15, 2017 by The Johnster

[ejstubbs]

 

I have to agree with EJS. Tension lock couplings are the most infernal things

 

I feel that needs to be qualified, and can speak as someone who has standardised on a single design of miniature tension lock for freight stock, and gets complete reliability operating full size trains, up to 60 wagons, pulling and propelling

 

Can I just point that what I originally wrote was: "You would not be the first person to discover that tension locks are decidedly inconvenient if you do a lot of manual rearrangement of stock within trains."  I don't doubt that it's possible to make tension locks work reliably for normal railway-based operations.

Edited June 15, 2017 by ejstubbs

[ejstubbs]

Kaydees have a major advantage in that I will be able to lift vehicles straight upwards out of the middle of rakes with minimum disturbance to their neighbours, and put them back with equal facility!  I am assuming that types are available which fit both the NEM pocket and the dovetail.

 

I think we may still have a bit of mis-communication going on here.  In the photo I posted previously, the dovetail is how the NEM pocket is attached to the chassis of the vehicle.  The NEM pocket is standardised, the dovetail isn't*.  The Kadee NEM couplings comply with the NEM standard.  That's all they have to do.  Interoperability between different manufacturers' equipment: it's what standards are for!

 

If all of your tension locks are NEM then (in theory**) all you have to do to replace a tension lock with a Kadee is to pop the "swallowtail" of the tension lock out of the NEM pocket and slip the Kadee's swallowtail in.  (Some people claim that you can just pull couplings out of NEM pockets.  I prefer to squeeze the end of the swallowtail together with fine tweezers, to free the protrusions at the end of the swallowtail from the lip at the back end of the NEM pocket and make it easier to pull the coupling free.  After all, they're not supposed to just pull out: they're supposed to couple stuff together!)

 

The annotated photos below may help to explain the terminology used, and the "anatomy" of the NEM tension locks in general:

 

 

 

* Actually, there is a standard for a dovetail-style attachment: NEM363 (whereas the more usual rectangular pocket is NEM362).  But NEM363 is intended for use "where space is restricted", and the coupling is supposed to fit directly into the dovetail, not via an intermediate NEM362 pocket.  The dovetail fitting as used to fit the rectangular NEM362 pocket to the chassis uses more space: if it's meant to having anything at all to do with the standard, it is a horrible bastardisation of it.

 

** I don't think anyone has yet come up with a standard which is guaranteed to be interpreted and implemented in exactly the same way by all manufacturers.  And if that could be done, there will always be instances where someone has, despite their best intentions, just plain got it wrong.  Yes, Bachmann, I'm looking at you and your early Mk1 coaches   Another common problem is "NEM droop": the standard seems to leave sufficient leeway for some NEM swallowtails to have noticeable vertical slack when inserted into a NEM pocket.  This can usually be fixed quite easily with a small shim of 10 or 15 thou plasticard.

Edited June 15, 2017 by ejstubbs

[DCB]

 I feel that needs to be qualified, and can speak as someone who has standardised on a single design of miniature tension lock for freight stock, and gets complete reliability operating full size trains, up to 60 wagons, pulling and propelling. (I expect to be able to perform any move with a train that the real railway performed, those sixty wagons have to be propelled reliably across any point ladder.)

 

Conclusion.

Select one design of miniature tension lock, mount it very carefully modifiying the commercially available mounting systems as required, adhere to the tested parameters for the layout trackwork and stock wheels, and you can have them working extremely reliably.

.

But which design of miniature tension locks? The old 1960s wagons had neat coupling mounts but some more recent attempts have ugly moulded carbunkles and retrofitting is approaching scratch building by the time a satisfactory mount has been cobbled together.  

Edited June 15, 2017 by DavidCBroad

[34theletterbetweenB&D]

...The old 1960s wagons had neat coupling mounts but some more recent attempts have ugly moulded carbunkles and retrofitting is approaching scratch building by the time a satisfactory mount has been cobbled together.  

 Oh for a whole new design coupler mounting point, through the bufferbeam where it ought to be. But what cannot be cured must be endured. I bought a fair mountain of both the Chiver's and Parkside moulded mounting blocks to take the 'dovetail' and it isn't too tedious to cement or screw these on.

 

But which design of miniature tension locks? ...  

 Either one or the other of the Bachmann or Hornby - tested in depth. The Heljan probably too, not tested exhaustively, and the Dapol and Oxford species look OK too, but not tested. Just use one type and one alone.

 

What with Bachmann going for global conquest in BR steam period wagons I had more of theirs than any other, so that was that decision made. Engaged in a mutally advantageous exchange with a 'Hornby Only Righteous Normative Brotherhood Yesman' charter member, his few Bachmen for my Hornboys...

 

Wasn't I the lucky one,  for it is the Bachmann design with a non-ferrous hook that works using the BK method for magnetically actuated uncoupling

[BR60103]

 

  Kaydees have a major advantage in that I will be able to lift vehicles straight upwards out of the middle of rakes with minimum disturbance to their neighbours, and put them back with equal facility!  I am assuming that types are available which fit both the NEM pocket and the dovetail.

 

One of our older club members observed that he'd never had a wagon disappear out of the middle of a train at an exhibition when it was equipped with tension locks.

[The Johnster]

I won't be exhibiting, but it's a good point!