I've made decent railings out of fly tying thread. Soak the thread in white glue and let it dry. Use unwaxed tying thread so the glue will work with it. I make stanchions out of larger thread that's been treated the same way and use a notched board (treated with furniture or floor wax so the glue won't stick to it) to arrange the stanchions and hold them for gluing the rails to it.
I'll admit though that I've been very lazy in recent years, resorting to the use of photo-etched railing.
