Several "cases" were screwed to the edge of the stage. Inserted into each was the railing post. The railing itself is made up of seperate 2x3's screwed down to the top of the posts. The first attempt to attach the rails were too stiff. This proved problematic. So, we changed the fastener to a simple screw. 

Take a look at the photo on the right. You'll see a crew member pulling on the strings. For the show, the stagehand was behind the curtain.