I think the scenery material often used to make trees for model railroads is called green polyfiber.
In the past I've made pretty good O scale trees using it with green flocking and spray glue. Like this:
I had some extra polyfiber, so yesterday I used it with flocking and spray glue to hide lock-ons and wires near mainline track. Like this:
If you do this, BEWARE!
After I did so yesterday, I ran one of my favorite locomotives: a Lionel Boston & Albany #618 made in the late 1980s (it has s great realistic whistle). When I ran it, it mysteriously slowed down and stopped. There was no derailment or short circuit.
When I checked the locomotive, polyfiber material got tangled in the side rod linkage.
I painstakingly and very carefully removed the polyfiber from the side rod linkage and the layout, tested the locomotive and it was fine.
I put another steamer, a postwar Lionel 2035 Pennsy K-4, another favorite, and ran it for 1 lap and again it mysteriously slowed down and stopped. Again, no derailments or short circuit. Same thing happened: polyfiber I forgot about that was still on my layout near the track got tangled in the siderods.
No permanent damage, so everything is back to normal after I removed all polyfiber that was any where near the track.
If you ever made a mistake making scenery, you can share it here so we can all learn from our mistakes.
Arnold