Author: Georg Helms
(EMail: [email protected])

If you want to do switching with somewhat realistic looking HO models of European prototypes, without using tweezers to handle original couplers, there is no way around Kadee couplers. But it does not look really elegant to use simply the NEM pockets with the matching Kadee versions: Instead, I install the Kadee couplers where they belong, that is in the center of the buffer beam. So they are located higher than according to US practice, and the modified models look like the Swedish/Norwegian Kiruna-Narvik stock, for example, or like some German experimental vehicles (see for example "Carstens, G�terwagen Bd. 3, page 154, 2^nd picture from above), or some British stock, like some of EWS� Class 66. Also, the present Z-AK, as used by the DB on some freight stock, does not look that much different.To make a long story short: Even if there are not many real prototypes, the modified models look like "could-have-beens" to me.

For real buffer-to-buffer-operation, the same conditions apply as described in the past for operating with original couplers: To avoid buffer lock, the used radii, easement curves, intermediate straights (between S-curves) and vehicle lengths need to be matched.
With 55cm (approx. 22") minimum radius, easement curves (15� of 80cm are sufficient!) and approx. 220mm max. vehicle length, things are going pretty well. With longer vehicles, also steam locomotives with leading/trailing axles (because of the long overhangs relative to the guiding driving wheels), you can let the Kadee couplers simply protrude further over the buffers, as these couplers - other than original couplers - are also able to push! So, with these few vehicles, you are not operating buffer-to-buffer, but you are able to use them, and it does not look so bad at all: The couplers in the center of the buffer beam are looking "logical", other than those low hanging close couplers (which I only use for passenger trains consisting of long eightwheelers, where you don�t see anything between the cars, anyway).
Of course, I remove the NEM pockets; they were always annoying me, by the way. The Kadee couplers are coupling exceptionally smoothly, as is common knowledge, can be (delayed) uncoupled magnetically, and can not only pull, but also push (see above!). If you ever pushed a train with Kadee NEM couplers, you might have bad experiences: The reason is, in my judgement, that that setup has too many joints, which is not the case with my way of installation.
Below I will describe the various ways of installation, and what needs to be observed to achieve really troublefree operation.

Vehicles with sprung buffers (preferred arrangement)

Here the long couplers No. 46 (resp.26 - same coupler, but more hardware for different installation options, which are not required here and make the 26s more expensiv than the 46s - but the 26 may be easier to get) with the relatively easy to install coupler box and spring of the "famous" US-standard type No. 5 are used. The buffer beam must not be thicker than approx. 1mm, to let the coupler protrude that much over the buffer faces, that the vehicles couple without the buffers touching: Otherwise the coupling happens only with some "violence" (to compress the buffer springs), and the magnetical uncoupling not at all. Anyways, the coupler box needs to be shortened to the length of the spring (deburr it if you use a saw or use a knife - just watch your fingers, although blood washes off nicely from plastic).
With thicker or in the center recessed buffer beams, the coupler No.36 comes handy: The coupler itself is the same as above, but the draft gear is shorter and can be shortened further. But: No advantage without disadvantage! The spring is a real bitch to install!

The No.4 is usually installed from below into an opening in the bufferbeam that matches the cross section of the box. The coupler box needs to be shortened, deburred (very carefully!) and rivetted together. If the front of the box is not exactly flush with the bufferbeam, it is optically not very distracting. It is important that everything is moving easily, "Greas�em" helps a lot! Before final fixing (you can temporarely use double sided tape for trial runs) make sure the vehicles run through your tightest curve without derailing: The No. 4 has less axial displacement than sprung buffers!
For final fixing I use two piece epoxy again. Don�t use real thin epoxy to secure the cover of the coupler box: This creeps inside the box and glues everything inside (yes, the hard way again...).
Wherever necessary, I fill up the buffer beam where it was cut out for the coupler with styrene strip to its original thickness. A small opening in the buffer beam and assembly of the coupler into a shorter box "behind" the buffer beam is possible, but not advisable: The short guided length of the coupler shank leads to such a high friction, that delayed uncoupling is usually prevented.

Above I noted already that the coupler height is not really critical. The coupler should sit in the height of the buffers, maybe a bit lower. But you have to be careful on some older Fleischmann and newer M�rklin models, as their buffers sit way too high - just check in advance! 12mm from rail top to buffer center is correct (some prototypes deviate slightly).
M�rklin eightwheelers, like the French/Belgian/Luxemburgian ore cars, can be lowered (wow, how much better that looks!) relatively easily after removal of the close coupling mechanism. On some M�rklin fourwheelers the buffers should be mounted lower than original (but this only helps if the axleguards are not too much "distorted"). The typical 0.5mm discrepancy of the newer Fleischmann models is not critical.
The uncoupling wires of the Kadee couplers need to be bent downwards for magnetic uncoupling per the instructions. Some wires needed to be bent "outwards" at the lower end for proper function.

Some notes regarding the uncoupling magnets: The strong under-the-rail magnet Kadee No. 308 also attracts steel axles, which are the only ones available for European vehicles. If you don�t like that (it�s no real problem for operation), use electomagnets (expensive and not really pretty) or a hinge for the 308s (see the instructions).
In either case, mount the 308 as close as possible under the rail and use the sheetmetal plate which is supplied with the magnet.
Now, have fun and a lot of patience! So far I converted some 150 vehicles. Difficult were only some locomotives, where I used a hacksaw (really!) to provide the space for the coupler box in the zinc underframe. I might invest in a power mill in my next life...