Graffiti wasn't just an artform,it was a way to communicate with a can.Remember there was no facebook or twitter or online gameplay,so you had to find other way to kill time.Some of the artist like SEEN,DONDI AND LEE became famous from this era with their work displayed round the world.I though painting trains white was a dumb idea,but it was intentionally done to determine which lines were heavily bombed with graffiti,so it was no surprise that the IRT cars got it the worst through Brooklyn and the Bronx.Stainless steel cars were less desierable to deface...It washed off to easily.