PC: Red PC Box Cars

[AGO3@xxxxxxx]

I was reading the article in Railroad Model Craftsman for Nov 1999 about the 
U33B when I looked closely at the picture of the Rock Island unit in the 
scrap line.  Behind it are several PC box cars.  One of them is red.  It 
looks as though its only difference is being red rather than green.

How rare is this red PC box car?  I've never seen one before.

A Olsen