Milan is often the last stop for migrants trying to get out of Italy and into other parts of Europe. Milan's central station, with its daily trains bound for the other side of the border, is a key strategic gateway out of the country.
European Union immigration law prevents asylum seekers from being able to simply buy a ticket and hop on a train. The Dublin Regulation stipulates that migrants have to stay in the country where they first claimed asylum. As a result, Italy is filling up with migrants who came by boat and don't want to stay there, as the country is notoriously bad at integrating immigrants into society.