Some things a person has to be taught and evidently even many so-called "traditionalist" pastors and faithful don't even know about or remember this custom of the veiled communion rail.
Today it's a rare sight.
The veil is often attached in this manner in Italy - via little metal pegs. Stateside, there is often a little curtain rod in which the veil is tied to with little cloth ribbons.
Before Holy Communion the veil is put up over the rail and after it is let down again behind the rail. 100% pure linen, make it happen!