I know as most all here about the problems that occurred with the older C track getting brittle. I don't want to go into that again.

What I looking for is a definite answer (if there is one) to when the problem of the plastic being re-formulated was completed? Does it coincide with the production moving to Hungary?

Also, I have found that this glue seems to work in cementing the little pieces back together. I have provided a link to show what the product looks like so you may be able to source it locally at you hobby shop or a craft/art store. I place the broken pieces in place and apply a generous amount of the liquid to the joint. Wait a second or two and them push the pieces together and you should see a bead of melted plastic ooze out of the joint. Then put it aside (overnight) until the cement evaporates and the plastic solidifies. Even after being repaired, I am still gentle when separating the track. Hope this helps!

Chuck

https://www.amazon.com/P...nt-Styrene/dp/B0006O09M4

How many tracks have been affected? If it's only a few, don't sweat it. Just replace them with newer track and have fun.

(A few tracks don't cost all that much; now if the problem is approaching 30, that may be different.)

Märklin has never pinned themselves down on this from what I have been able to learn.

I had a 12 year gap in buying Märklin and after I came back in 2016 all if the new formula track which I bought has the natural looking graphics, where the track base is dark like the real thing. The old track had the tried and true graphics where the track base was depicted in a light gray, which is not realistic. Maybe that is the magic way to tell the two apart.

Tom convinced me that the new C track is worthy and from what I can see so far he is correct. I was ready to chuck it all when most of my old C track broke when I got it out of storage - but I have yet to have any problems with the newer C track and it stays connected very well in the temporary bits. It snaps together better and stays connected much better than the old formula track ever did.

I think a "definite answer" can only come from Märklin, that's why I mentioned them.
Mere mortal forum members can only collect and summarise observations.
In my experience many questions sent to Märklin remain without reply - and many that receive a reply remain unanswered.
A definite answer from Märklin could be positive for Märklin, limiting the irritation caused. Recently this topic came up several times on Fartbook - and the easy answer there was "brittle => Made in China". Very useful indeed. I think C track was never made in China, but I can only offer speculation, Märklin could offer facts.
A definite answer would be of interest for anybody dealing with second-hand C track - as a buyer or a seller. If the time frame for brittle track is small then a definite answer could even improve the reputation of C track.

It seems they still exchange the 60173 boosters (no galvanic insulation), the bally electronics of mfx/c-sine locos, the C track turnout motors, brittle frames of US box cars, ...

No more free replacements for brittle C track, brittle Seetal crocodiles, brittle Köf II.
Can we draw any conclusions from that?