Have you ever wondered what eternity actually looks like?
Can you ask for a more captive audience than drivers waiting for a freight train to pass? How about putting together a complex ad running from car to car? How about a stop-action “movie” with a scene on each car? Riddles which are answered on a later train car? A count-down of how many cars are left in the train? A comic book series?
In two minutes I could think of all sorts of cool designs that would take advantage of the captive audience, and relieve the boredom of waiting for the freight train to pass. Now you have a potential customer who you’ve already made happy just by providing them with entertainment (unlike TV commercials where you start by making potential customers unhappy by interrupting the program they are trying to watch).
Of course there may be logistical and design challenges with running ads down the side of a long train, for example:
What can you do about train car size variance?
How do you deal with the fact that the order of the cars get switched around over time?
How can you best serve the people who do not arrive in time to see the entire train pass by?
What can you do to make the designs simple to attach, remove, and update?
But all of these sound like fun challenges to try and resolve!