I built a 5 deck 027 layout which I call "The Crazy Train". To prevent derailments, rollovers and falls I built some guardrails from 20 gauge galvanized steel "L" brackets (which I fabricated) and monofilament fishing line. It works really well. See the pictures below.
I am going to build another larger 4 deck layout with 031 track.
Does anybody have any ideas for easier alternative railings?