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Use of Kadee couplers on British stock.

Mike McHugh provides further information on the use of Kadee Knuckle couplers following an article of his published in the HMRS News for September 2001.

Some while ago in a branch report in HMRS News there was mention of Kadee couplers and the suggestion that they may be used for special applications such as close coupled stock.

Well I think that is back to front, I use Kadee's as standard and hook and bar for special applications such as close coupling! Why? You may well ask.

I live "Down Under" in Canberra, the capital of Australia. The Kadee coupler is almost the standard used by modelers of Australian and US prototypes and hence is easily available locally. It is also used by a number of local British prototype modellers, so it was a fairly obvious choice for me. The only real problem with it is that it does not look much like a hook and chain, but it does work very well and is easy to fit to the majority of stock.

So where do you start? There appear to be so many different types of Kadee coupling and it is difficult to know what to get first!

The main differences in the types are in the mounting arrangements and once you have worked out what is what it is this variety that makes them easy to fit to any vehicle. Kadee do make couplings for other scales and for narrow gauge use, so these also add to the confusion, and possibilities for that matter!

The "standard" HO Kadee coupler is the No 5 and like all Kadee's these come in packets of 4, i.e. enough for 2 vehicles. Since they are so commonly used they are often sold in packs of 10 packets, i.e. 20 vehicles worth and this way are usually about half price.

Like all couplers you need to work out some basic principles so that you get the vehicle couplings together everywhere you want them to, but not having excessive gaps between the buffer faces. After some experimenting I found that N0 5's will mount on any stock with 1ft 6in buffers almost as Kadee designed them, provided your curves do not exceed about 4ft radius. Remember that Kadee designed them for stock without side buffers. With the draft box sitting a little proud of the headstock No 5's will fit on stock with longer buffers. Whether this is acceptable or another of the Kadee variants is used is a matter of personal preference. The most likely one to use is the No 16. Kadee say this is for use with European stock and it has the longest shank of all the variants. I only use it where either the buffers are very long or the mounting point on the vehicle has to be further back from the headstock than usual. Since buffer lengths vary I align a particular point on the coupler with the buffer faces, for my purposes it is the rear face of the inside of the knuckle, on tighter radius curves this will have to mount further in front of the buffer face.

In this experimenting I also found that by mounting the coupler immediately below the headstock, i.e. the top of the coupler draftbox is in contact with the bottom of the headstock, the coupler was at the recommended height. This makes mounting very easy on most stock.

Usually I fix some plastic card behind the headstock to make a mounting plate and screw the assembled coupler to it. I usually use 2mm or 10BA screws, depending on what I can get hold of easily, through the centre mounting hole. I drill and tap the hole, but it is possible with plastic card to get the screw to cut its own thread.

On coaches I mount the coupling in exactly the same way as wagons, on the coach body. This usually requires a bit of modification to the end of the bogies, like cutting away the bar between the sideframes, surprisingly most are just as reliable without any connection between the sideframes as they are with one. As long as you don't expect to be able to couple on curves the Kadee will work mounted on coach bodies even through tight reverse curves such as a crossover. In fact the typical British coach is short compared to the long container flats used by Australian railways and it is interesting to watch models of these with Kadee's mounted on the bodies. There is nowhere else to mount them as the bogies are set a long way from the end giving a very large overhang.

The most difficult vehicles to mount Kadee's on are locomotives, especially tank locomotives. Again I usually mount the coupling on the body but simple plastic mounts are not always possible. Sometimes it is necessary to add metal brackets or other means of providing a mounting point. It appears from the Kadee literature that the primary reason for the variety of couplings is to accommodate all the varieties of model US locomotives, so it is not really surprising that this is where we have the most trouble with British stock. Usually I end up with a coupling from the series No 31 to No 39. This is a set of 9 different couplings with the same type of draftbox but designed for mounting with the draftbox at different heights between 13/32 inch to 35/64 inch. There are 3 different lengths to the shanks of the couplings and the ones with the underset shank are particularly useful in allowing for the deeper buffer beams often be found on locomotives.

That gets the coupling onto the stock, so what else is there. The trip pin needs to be adjusted after the coupling is installed and it is worth buying the Kadee jig for this, or at least setting up your own jig. The object is to set the bottom of the trip pin as low as possible without fouling rails on turnouts and crossings.

Then there are uncouplers. Kadee supply 4 different types including delayed and non-delayed permanent magnets and electromagnets. Electromagnets are definitely the best, unwanted uncouplings when moving slowly over permanent magnets can occur. The Kadee electromagnet sits between the rails and is visible. I have seen layouts at exhibitions with home made electromagnets mounted under the rails and working very well, but haven't tried to make any of my own yet.

Finally there is the vehicle weight, but that is a problem for all couplings and for general running. This will generally need to be experimented with until the best operation is arrived at. Generally RTR stock and plastic kits are too light and need to be weighted to something over 25 grams. I generally end up with 4-wheel wagons at around 35 grams which is limited by the amount of additional weight you can fit in an open wagon that does not have a load.

There has been much discussion on the British Railway Modelers of Australia (BRMA) Electronic mailing list about the use Kadee's on British stock. This is an open list and can be found on the Yahoo Groups site, it's called BRMAEG, or via the BRMA web site at www.brma.asn.au . Similar discussion has also occurred on the BritRail list on Yahoo Groups.

The Kadee web site itself is also very useful as it gives drawings and descriptions of most couplers and can be found at www.kadee.com.

All the text in this article is copyright Mike McHugh and may not be reproduced without permission.

This page last updated on
13 December, 2007