This .blend contains a container model as they are usual all around the world for shipping etc.
They are called ISO containers and this model is very fitting for industrial scenes etc as a nice scene filler.
The material setup is made to color the paint with an RGB wheel in the node setup, but not the rust.
Thanks to Dennis Haupt who donated his computer for rendering the preview.
When using this file give credit to http://manuell3d.wordpress.com