[dvd3500]

I have no idea who this guy is and I will not profit in any way but I saw this item when i searched for 2catch fencing" and thought it wasn't too terrible:
https://www.ebay.de/itm/Carrera-GO-Digit...Sw55FcOTAe
He took a sponge you use to get insects off the windshield and cut it into the shape he wanted and used a marker to draw bailing wire on it.

I am thinking some string would look more realistic and be almost as easy and at a cursory glance they don't look tooo bad.

Affixing them to the track may be trouble but I reckon double-sided tape should do it.

Maybe a dash of spray paint to get them a more realistic color...