All of what I've seen most recently had load of wood wrapped. I guess there are still loads not wrapped. I would like to model both because it's just more interesting to have different loads.
Nice work going on here.
Dave
Here's one that I shot less than 2 weeks ago:
http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=nokl738305&o=nokl
Wrapped far outnumbers unwrapped these days though.