Telltale construction

I would like to build a few telltales as warnings at tunnel approaches
on my layout.  Now comes the (I hope not too dumb) question.  What is
the hanging part of the telltale made of?  Pictures of model telltales
that I have seen are ambiguous at best, and the few prototype photos
I've seen are so blurry and distant that they are useless for my
purposes.  I would think that lengths of rope would be the most
logical material, but I thought I'd ask before doing something very
unrealistic.  Thanks in advance for any replies.

Michael Valinis