It will work in many cases but unfortunately, **not always**.
However, there is a simple solution,: I use Roco 40397 couplers, which are Märklin KK compatible **and** work actually more reliably than Märklin originals
Here is what they look like and where I get mine and other coupler paraphernalia

http://www.schnug-modell...Kupplungen/IMG_0463g.jpg

Hope this helps

Jacques

I have several Roco wagons which I have fitted with Marklin close couplers and they work perfectly with all my Marklin wagons and locos.

Occasionally you get a wagon where the Marklin couplers foul the buffers because, as Tom pointed out, the Marklin buffers are mounted higher than other manufacturers.

Couplers which are on standard NEM mountings, as all modern wagons tend to have, can easily be swapped around. My advice is to try it and see. If you get a problem with one particular wagon then change it back to Roco or other couplers.

I have never been very happy with Marklin's close couplers. They are difficult to get the cars to couple, most times requiring several attempts. This makes them at best frustrating and at worst completely useless when doing work in a yard. They also do not remain reliably coupled. On M track in particular you can't look away for a moment or you'll have some crash because a coupler let loose. I think part of that problem is due to the loop being closed. Because the loops are not open asymmetrical hooks, one loop must always rest on top of the other. When on top, it will just lay there as it cannot fall behind the hook on the coupler. So you will always have only one of the loops holding the two cars together. You can see this clearly in Tom's blog linked above, sixth picture down. I have also had the same problems as others with fouling against buffers as the car passes through a curve or switch. This fouling will lever the wagen off the track. I knew I needed a replacement.

I have had great luck with the old Relex couplers. They couple reliably and although only one loop typically holds the cars together (as in the picture below), the taller hook means they will stay coupled. So I tried the 72060 NEM pocket compatible Relex coupler. I had no more problems with cars uncoupling, but the close coupler mechanism on the wagen would cause the coupler to collapse when pushed through curves or up hill. This meant the coupler was not centered over the track and an uncoupler would not release the coupler. If the clearance between the coupler and buffer wasn't enough, the wagen would get levered off the track. So that didn't work.


So I thought I would try the Roco 40397 couplers. Tom and Jacques had good luck with them and I needed a fix for the problem. I have now replaced just under 1000 couplers. These things are really sweet. They couple every time and even on old M track, I never loose a wagen. The asymmetric "loop" means they will nestle down next to each other clearing the buffers and engaging both hooks for a 100% increase in connection compared to M's couplers. All my freight wagens and lokos have been replaced and about 10% of the passenger wagens. The other 90% use M's current conducting close coupler. These too are difficult to couple, they are the same design, but they remain coupled due to the load the conductor places on the loop and hook. Since my passenger wagens are essentially fixed consists, the difficulties on coupling are not so much of a problem and each end of the consist now has the Roco coupler. If the current conducting couplers still foul on the buffers, or in my case the diaphrams on my Blauer Enzian set, remove the loop on the opposite coupler. Now you will not have it just laying atop the other getting in the way and the load on the hook created by the current conducting contact will still keep them coupled.

The old M couplers are into the trash bin, for some reason I think I should feel bad, but I am only all to relieved to fix a problem that made operating a railroad extremely difficult.