[dvd3500]

I can double check later but I think Ninco is something like .5 mm thicker than Scalextric/SCX making it OK to put Ninco on SCX/Sclaextric but not the other way around.
Having said that, the very rare clips and barriers pack from Scalextric does not actually have a "tongue" to go on top of the track and should work. Worst case would be you have to use a saw to make the gap a little larger. They are, however very rare....

I think Carrera is a similar thickness bot not 100% sure. I personally don't like the Carrera barriers much though. Here in Europe (Germany) there is a brand called Cartronic that makes nice borders that ought to fit but that might not be an option for you...

In a pinch, you can take 5-8 mm thick foam rubber (available in many colors) and glue or use a drill and a washer/screw combo and attach them directly to the track. If you glue printed advertising onto the foam rubber (be careful, most glue will not work/or will damage the foam rubber) it doesn't even look half bad.

Advantage is you can cut to length and make it any height.


There are also options out there with rain gutter mesh, fine mesh grating and even things found in food packaging!