Dodgy Couplings

[New2N]

[quote=

Lacking that answer, then pragmatically, I would suggest that you inspect all your stock for coupler height, and either go for the average (arithmetic mean) height, and reset as required, or select the most frequently occurring height that works really well and reset as required. The latter may well be least work.[/quote]

I have inspected the couplers and I know which ones are low, the ones on the locos. How do I reset them? You make it sound as though it is simple.
They are all the NEM pocket type.

[New2N]

Being relatively recent models that you are talking about I would take it that the couplings are of the clip in place into a mount type allowing other types of couplings to be readily fitted - now it might be there is some slop in the fitment which is causing some couplings to drop below normal height;
certainly this can be an issue in OO and the solution there is to slip a thin piece of suitable material in the mount underneath the coupling to support it at around the correct height. Maybe something similar is needed. If some couplings look slightly too high then it could be they are at the other end of tolerances and it would be worth trying swopping the over high coupling with an under height coupling.

Thanks for your suggestion. They are indeed NEM pocket devices and I had thought about packing them appropriately, I just wondered if there was a more 'professional' solution.

[Bigmet]

...I have inspected the couplers and I know which ones are low, the ones on the locos. How do I reset them? You make it sound as though it is simple. They are all the NEM pocket type.

Much as Mike Parkes has already suggested, you need to look closely at whether the coupler pockets are properly located, see if there is room to insert some thin packing (a 'shim') in the pocket to raise the coupler, look at the locator on the coupler to see if some are out of position, and there may be more possibilities. In OO pockets can be turned over to use a veritcal assymetry in the moulding to alter coupler height, and the mounting on the vehicle can be cut into to allow the pocket mounting to rise, and the locator on the coupler can be filed, so that thicker packing can be used to move it up or down. Not having looked at N with coupler pockets, it's not something for which I can offer proven ideas for N unfortunately.

[New2N]

...I have inspected the couplers and I know which ones are low, the ones on the locos. How do I reset them? You make it sound as though it is simple. They are all the NEM pocket type.

Much as Mike Parkes has already suggested, you need to look closely at whether the coupler pockets are properly located, see if there is room to insert some thin packing (a 'shim') in the pocket to raise the coupler, look at the locator on the coupler to see if some are out of position, and there may be more possibilities. In OO pockets can be turned over to use a veritcal assymetry in the moulding to alter coupler height, and the mounting on the vehicle can be cut into to allow the pocket mounting to rise, and the locator on the coupler can be filed, so that thicker packing can be used to move it up or down. Not having looked at N with coupler pockets, it's not something for which I can offer proven ideas for N unfortunately.

I am fast learning that N is a far more difficult and problematical scale than OO. The N gauge pockets are so tiny that I am struggling to find anything fine enough to 'shim' the coupling box. I have instead applied a spot of tacky glue to the adjusted coupling and will see how that works tomorrow.

If that does not work I will make a permanent rod type coupling or superglue the existing couplings as I cannot see me shunting or separating these trucks and locos.

What I have difficulty in understanding is that you can buy new wagons and a new loco, from the same manufacturer, which just do not couple up properly.

[Bigmet]

...I am fast learning that N is a far more difficult and problematical scale than OO. The N gauge pockets are so tiny that I am struggling to find anything fine enough to 'shim' the coupling box. I have instead applied a spot of tacky glue to the adjusted coupling and will see how that works tomorrow...

Yes, the small size is one of those aspects you have to learn how to work around by your own experiment, and learning from other's experience and advice.

I think you might do well to post in the N gauge section with a title like 'Coupler height adjustment' as none of the N gauge users on this site appear to have spotted this thread, and they will hopefully have good experience to share.

...What I have difficulty in understanding is that you can buy new wagons and a new loco, from the same manufacturer, which just do not couple up properly.

The 'reasons why' can be many and varied, ranging from constraints on the coupler mounting position caused by the prototype design, manufacturing limitations, simple error in design that wasn't detected before production tooling was cut, and even possibly lack of awareness of the correct position.

In my opinion this problem should be brought to the retailer's attention, as an aspect of the product that the manufacturer needs to get right.

[Byegad]

...Is there a simple solution to this problem.

Simplest? Return to OO!

It is very simple indeed, N demands considerably more care and developed skill in the matter of stable baseboards, tracklaying and optimisation of the set up of locos and stock to achieve equivalent results to OO in running reliability. If you can patiently work at that, very good results can be yours. I for one don't possess the patience, because I can practically throw together OO (RTR and hand built from kits and scratch) with great reliability, and just cannot do this in N gauge. But, YMMV, and you can only find this out by trying. All the best with it!

At exhibitions, remember them? I often see 00 layouts with quite ropey track, in that the joints show a scale 3-6" gap, and a similar difference in rail height at the join. The standard 00 coupler, which as a Hornby Dublo* child I always think of as the Triang one, with a loop and hook arrangement, seems to be very forgiving.

In N some basic care to get the joints pays dividends and the judicious use of a mini grinder or file to get level joints makes decoupling a rare event, easily avoided by checking/adjusting coupler height and a dab of Tacky Wax, usually for Peco wagons where there's no spring effect to avoid one coupling jumping up, say on a point and leaving the rest of the train go off.

*H-D used a metal, later plastic, coupling more like the N gauge standard 'Rapido' which worked fine on my boyhood trainset.

[Bigmet]

...At exhibitions, remember them? I often see 00 layouts with quite ropey track, in that the joints show a scale 3-6" gap, and a similar difference in rail height at the join. The standard 00 coupler, which as a Hornby Dublo* child I always think of as the Triang one, with a loop and hook arrangement, seems to be very forgiving...

You are not wrong! This 'crash along' characteristic in OO is pretty much 'locked in' as the standard which RTR OO product must tolerate, by the standard set track point, which has a ruddy great 'hole' at the point crossing among its several unlovely characteristics.

The only RTR OO manufacturer with a significant range that ignores this requirement is Heljan, employing a narrower tyre and much finer flange on their loco wheels much to the advantage of their model's appearance. Now, this does occasion some comment about 'track sensitivity' of their product, but there's no overwhelming negative feedback (it's fine on Peco streamline and equivalent). This may change with wider distribution of some Heljan items via the EFE brand marketing, wait and see on that one.

Although the 'tension lock' is pretty tolerant of poor track, it is nowhere compared to the continental HO 'hook and loop' coupler. The best examples of this design will remain coupled over vertical movements far greater than the stock can tolerate, without constraining that movement at any point before the wheels come off the rail of their own accord.

...H-D used a metal, later plastic, coupling more like the N gauge standard 'Rapido' which worked fine on my boyhood trainset.

Which was of course the 'Peco Simplex', H-D paying a licence fee for its use, and all these years later Peco still sell it in the superior original metal form. It's something of a shame that Peco never progressed development of this coupling principle; Kadee introducing the modern equivalent, a working representation of the prototype knuckle coupler, and have gone on to achieve 'world domination' in this coupler design...

[Ironduke]

the N scale NEM pocket is very different to the HO/OO version. there is certainly no room for shims. It seems the coupler is retained in the socket with nubbs either side, which double as the pivot that the Rapido coupler levers up from.

I model n scale American trains, which don't use anything like the NEM socket, so the only advice I can offer is, make sure none of the Rapido uncoupler pins hang lower than the track surface. If they hit anything like a point blade or level crossing they may flip up or snag which can cause upcoupling and derailments. With the Amercian knuckle style couplers you can bend the trip pin upwards to avoid this. I suppose with Rapidos you'd have to cut the pin?

Photos would definitely help here. I would like to see how much higher or lower the couplers actually are.

[Bigmet]

the N scale NEM pocket is very different to the HO/OO version. there is certainly no room for shims. It seems the coupler is retained in the socket with nubbs either side, which double as the pivot that the Rapido coupler levers up from...

That's helpful to know, because it rules out the shimming into the the pocket that one can do on the HO (OO) NEM coupler pocket. Which is a bind, but nothing can be done about it.

[inoffapost]

Glad to have come across this thread although the original post related to N guage kit.

I'm using OO and have acquired some Dapol products, all new. The wagons themselves are incredibly detailed so full marks for that, but the operational experience has not been so good. The couplings are poor, frequently detach from either the loco or other wagons - with the same couplings - buffer lock on points and R2 curves and regularly derail over points (all track checked and points are new). I'm starting to think they are just 'show' models and not much else!

I have a number of ROCO units and the coupling system NEM 'Loop' system NEM362(?) works so much better. I'm seriously thinking about swapping the UK hook tension lock couplings out wherever possible. Such a shame, and such a frustration. All the care and expense that makers like Dapol invest in the model and yet the product ( I speak only of bogie wagons here) is operationally poor.

I'm a new modeller this year and it has been a steep upward learning curve. Just when you have the layout built and wired up and it all works and then you have endless problems with the RTR kit that should be turnkey and 'ready to run' and not BTF (built to fail).

Oh well, more like the real thing than I thought

[Bigmet]

...I'm using OO and have acquired some Dapol products, all new. The wagons themselves are incredibly detailed so full marks for that, but the operational experience has not been so good. The couplings are poor, frequently detach from either the loco or other wagons - with the same couplings - buffer lock on points and R2 curves and regularly derail over points (all track checked and points are new). I'm starting to think they are just 'show' models and not much else!...

My personal experience of Dapol's OO product is very limited, one loco (their recent class 21, very good) and probably now ten or more years ago a sample of three wagons, two four wheel and one six wheel, all dire in multiple respects, not buying any more of that! (Their product range overall doesn't suit my interests, the class 21 was the first 'essential item' they have ever produced, and happily it is a goodun.) So what follows is 'principles' rather than specific advice about the wagons you own.

Are these Dapol wagons giving trouble all bogie wagons? If so the buffer locking and derailment on R2 curves and points suggests that the couplers are incorrectly positioned; typically caused by the 'NEM 362' coupler pocket location not being correct, relative to the fixed structure of the vehicle end. Here's a guide to correct location, which you can use to check the coupler pocket positions.
http://www.doubleogauge.com/standards/couplings.htm

(Unfortunately it is not just Dapol that have fitted these coupler pockets out of position, and we RTR OO users have grown accustomed to coping with this when it happens. We can discuss that if coupler pockets out of position proves to be the case.)

...I have a number of ROCO units and the coupling system NEM 'Loop' system NEM362(?) works so much better. I'm seriously thinking about swapping the UK hook tension lock couplings out wherever possible...

Now Roco. This is of course one of many HO manufacturers. Generally in European HO, the NEM 362 coupler pocket is installed correctly positioned, and you can swap the various coupler designs intended to fit in these pockets freely as a result. But if the pocket isn't correctly positioned, then use of an alternative coupler to the miniature tension lock typically found on RTR OO is equally troublesome. So the first step is to wave a ruler over the coupler pocket positions...

[inoffapost]

Thank you for the link Bigmet. I'll get the ruler out and do some measuring!

Are these Dapol wagons giving trouble all bogie wagons?

Yes. I bought a number of the Sliding hood coil carrying wagons last year and to varying degrees they all cause problems, but not all the time! Even more annoying are the derailments which sometimes even occur on straight track. This model feels quite light, so I've loaded the mock steel coils provided to offer more weight. Tests are ongoing. Clearly checking all the track; joins and alignment etc, was and is a must, but then again, the ROCO and Bachmann kit I have give no problems.

In addition to the coil carriers I have a 5 set of the MRA Side tipping wagons which have 2 'outers' and 3 'inners'. The outers couplings are similarly flaky I find but more inconvenient is a de-railing issue on one of the outers on straight track! Bizarrely, the first axle on the trailing bogie derails over a track join. The join is flat and completely closed and there is absolutely no obvious impediment at the point of derailment. Interestingly, these wagons are quite heavy with most of the weight generated by the 2 side tipping containers which sit on the wagon chassis, much like a container flat. Remove the containers....hey presto! no derailment. Add the front container...no derailment. Add the 2nd over the rear bogie...off it comes! So clearly weight isn't always the answer. I'm at a loss with it. There is no bodywork fouling issue, the wheels are running free over this track joint. I may just exchange the track section to cross that one off the list but I think it is a wagon issue. Like I said in my first post...just like the real thing really!

First things first though......ruler out!

[New2N]

Reassuring to see that I am not the only one struggling with modelling in a, new to me, smaller gauge.

Like you Inoffapost, I found that a bit of weight in the wagons improved the situation but I was still experiencing inexplicable derailments. In my case I found that the axles on the bogies dislodged from their sockets all too easily and that this was often the cause. I have mainly solved the ghost uncoupling problem by deploying the semi permanent coupling rods that came with the wagon packs I bought.

I also have a Dapol HST set with one additional coach. I have used the connecting rods on four units with standard couplings left on the additional coach and depending on which way round this coach is placed on the layout, the train stays together or leaves half the passengers stranded.

If the connecting rods I am using were available in a shorter length, the ones I have are just too long, I would happily buy some but I don't know if they are available.

I think my biggest problem is that I devised a OO track plan for an N gauge layout. Too many passing loops and sidings involving a proliferation of points and two gradients. Maybe I should have kept the track plan simpler and concentrated more on scenery etc to fill my time through this long winter period.

I have no experience with any other N gauge brand other than Dapol. In OO I find Dapol kit to be very good, it is Heljan where I find the couplings to be a bit limp and dangly.

[Bigmet]

... derailments which sometimes even occur on straight track...

Ah, now this event is unlikely to be caused by the couplers. Part of the 'direness' of the three Dapol wagons I have purchased was that two of them came fitted with wheelsets with unacceptable profiles. These would find ways to derail themselves 'spontaneously'. Take a look at the wheels in the troublesome wagons. If the tyres are cylindrical, and the flanges are at a right angle to the tyre, with coning on the back or inside face of the flanges to a near knife edge tip, these are the trouble.

Good model wheels actually follow the prototype, the tyre slightly coned - this makes the wheelset self centering on track - the flange also coned, with a dadiused transition to the tyre, and a rounded tip, and the wheelback flat at a right angle to the axle. The flanges are only majorly called into play to prevent derailment on point crossings, on plain track the coning of the tyres does most of the work.

A cylindrically tyred wheelset doesn't generate any self centering action, it just wanders about on the rail, and when a flange with a sharp tip meets the rail it can climb it and derail the wheelset, and thus the vehicle.

A comparison between a range of trouble free wheels and the derailing specimen(s) should confirm whether or not this is the trouble.

[inoffapost]

Part of the 'direness' of the three Dapol wagons I have purchased was that two of them came fitted with wheelsets with unacceptable profiles. These would find ways to derail themselves 'spontaneously'. Take a look at the wheels in the troublesome wagons. If the tyres are cylindrical, and the flanges are at a right angle to the tyre, with coning on the back or inside face of the flanges to a near knife edge tip, these are the trouble.

Thank you again Bigmet, this will be well worth doing, just to eliminate another option. It could also be the answer to another set of 'spontaneous de-railers'. I was working for GE back in the day and during an office clear out rescued a boxful of Jouet 'Cargowaggons' from the skip. Brand new, never been used. I thought 'one day...maybe I have a model rail layout.....'
Well, now I do, and a rake of these things would look very good. They are very long so R2 is the absolute minimum, but during testing a number have displayed an odd tendency when exiting a curve, R2, R3, doesn't matter, the leading axle on the bogie, leading or trailing, will visibly ride up momentarily, so to speak, and then derail. For all the world it looks like the wheelset has run over something, but there is nothing there. I've conducted the experiment multiple times by hand pushing at creep speed and you can watch it occur in 'slo mo'

I had already decided that it must be the wheelset(s) as I couldn't imagine another explanation, and to exchange them for something else. I shall examine them closely and carry out the comparison. Out of the dozen units I might be able to get 4 or 5 'good' ones assembled, and then re-fettle the rest when I have found suitable wheelsets. Never a dull moment with these things is there?