Graffit-ed box car as public art

When I saw this car, I wondered if it had been done with the approval of the train car owner, because the specific identification information for the train car was not obscured by the paint job. 

Then, it made me think, why not have a "public art" program featuring art graffiti treatments of box cars?  It certainly would be a way for a transportation company to differentiate their brand.  Although most in the industry would probably frown on the choice, believing it would encourage graffiti where it wasn't wanted.

-- "The Art of Freight Train Painting," Saturday Night Magazine, Canada, via Utne Reader
-- "We were here: Marks, Monikers, and the boxcar art tradition," Matthew Burns, masters degree thesis, Lehigh University, 2005

Although I am not sure this is what I meant when I lay out the concept of "transportation infrastructure as an element of civic architecture."