the DVD for Scratch 2: All the Way Live has a cool bonus feature with shepard fairey (
http://www.obeygiant.com/ ) that gives a super quick over view of where, when, and how to get your posters/images up.
as for the train stuff, there's an Art:21 video series put out by PBS with a segment on barry mcgee.
check it
http://www.pbs.org/art21/artists/mcgee/index.html#
and click on the "writing on trains" link on the left for a tiny taste.