Don Wiss wrote:

I have a deck about 12 feet square. The railings are wrought iron and 42"
high. I could mount some light on the wall on the side that is against the
house. Better lighting it seems is on the railings. But when I search the
web all I find are for wood railings.

Don www.donwiss.com (e-mail link at home page bottom).

Best is small white courtesy lights made for use on boats. Mount on the
underside of the metal railing, mounting and wiring will be a pain in
the butt. Power from a suitably sized low voltage landscape lighting
transformer.