What is a fuel rail?

What does a fuel rail do?

deliveres fuel to the fuel injectors (i think)

A fuel rail delivers fuel to the injectors...

So if you look at your engine, just above the intake manifold is the injectors, and the fuel rail runs along the top ends of the injectors...

The red thing in this pic is a aftermarket fuel rail.

Sorry for the big pic btw.
http://www.automotiveforums.com/kris/kris/civic/11_26/11_26%20002.jpg