For as briefly as it appears, I’m Shipping up to Boston leaves a lasting effect on The Departed. Miles away from the classic rock and punk that Martin Scorsese often uses to soundtrack his films, the Dropkick Murphys song places the movie in very different territory. Based on a Woody Guthrie poem, the song recounts the story of a sailor who lost his leg climbing the topsail. Sure, it’s a tale out of time, but the Murphys bring a rage and chaos to it that makes it seem current and raw. Their mix of Celtic instrumentation with punk rock rarely produces compelling results, but on this particular track they seem to have stumbled on to a winning combination. Quick and sharp, it’s Black Flag meets Celtic folk. The guitar and accordion combine to form a wall of noise that’s at once spritely and aggressive. The ragged call and response creates a tribal feel, reinforcing the gang-like mentality of the film’s characters. The whole scene, and the whole film, balances on the edge of the knife for those characters, and the song expertly conveys the tension that they feel in those moments. It’s an expert choice, communicating atmosphere, history and personal emotion in a matter of seconds.