The SNCB (national railway company of Belgium) did a 3 minutes video about the buff in Belgium. The buffers tell us how they do to erase the graffiti that appears every day on the railway.
The video in French is conming from the SNCB TV channel and is now available on Dailymotion.

[dailymotion]http://www.dailymotion.com/video/x105fnh_nettoyage-du-graffiti-sur-trains-en-belgique_animals[/dailymotion]