Originally Posted by: baggio 
Originally Posted by: PJMärklin 
I am not sure what you mean, by way of your double negative, could you please clarify what you mean
I meant that my usual habit of using C track (or all other track I have used) WITHOUT spending time and effort in ballasting the track, so as to use it "right out of the box" does not work for K track; meaning that K track are meant to be ballasted, with cork or other material, and NOT to be taken down and re-positioned a few months later.
Hello Baggio,
Thank you for your reply.
May I precede my response by noting that we all enjoy Märklin in numerous and diverse ways and I respect every one of them.
If your modus operandi is "out-of-the-box" or to be dismantled and re-assembled then perhaps K-track is not for you, but this is an individual decision.
However this is my K-track story:
In the mid 1980's when I became very interested in Märklin I carefully considered how I wanted to go about it. I decided that I wanted a "permanent" (are they ever complete or permanent ? ) layout with "lifelike" track and "roadbed", signals (I decided on Brawa), stations and related areas, realistic overhead catenary (I decided on Sommerfeldt) and scenery (I decided on Woodland Scenics).
Looking at the available track from Märklin I decided on K-track (being aware of the extra particulars required with use of K-track)
Not long after, C-track became available but I did not think the "ballast" was lifelike-enough to come near the K-track with appropriate ballasting.
Thus I settled on K-track. It clearly needed roadbed ballast and peripheral ballast to make the most of it's realistic appearance.
I searched further. In my first layout I used Mössmer, a foam plastic, molded to various, including Marklin K-track. This is now currently produced by Noch with some adherent ballast granules. However I found that the foam deteriorated after 10-15 years and became a contracted degenerate gooey mess:


In my current layout (built commencing 1998) I used Merkur roadbed/ballast underlay for the K-track. This is a different substance : it is very firm, fits well with the K-track :




After 18 years it shows no signs whatsoever of deterioration:



and has a matching scatter-particle ballast that can be used for peripheral and associated matching ballast:



In some areas I did not use Merkur roadbed and used either Woodlands ballast or my own mixture of various (mostly Faller) ballasts, such as at station platforms :


in the freight yard :



and in the steam service area :




So my response is this : to each is own, we all enjoy Märklin in an eclectic manner. If what you want is K-track and if you want it to look more realistic than stand-alone (but resisting the obsession of the "rivet-counters" - not that there is anything wrong with "rivet-counters"- we need diversity in this life) , then the most "realistic", long-lasting and convenient "roadbed" is Merkur together with the matching scatter ballast plus other ballasts to taste.
Just my humble personal experience and opinion.
Regards,
PJ