Looks nice.
One way are barrel clamps. Find some with two tandem set screws. Thinner?Maybe uninsulated crimp connectors; thinner yet, metal tube and epoxy or solder. If you can terminate in a pole, just butt two poles together.
98%+ of my derailments happen to the outside of curves. I've had two divers; both before I perfected the track (old, graded). But not plastic locos and both were ok. The infrequency and perfecting trackwork stopped my railings from ever being put up. If I was going to sleep under it while running, I might add one overhead.
Captain Hindsight says; The railings could have been camouflaged bus wire. Depending on how you wired things, bus or just tracks, you might use them to fatten up your center rail side of the feed? It only has one rail worth of delivery ability vs the 2 outers 
