A new report on the cleanliness of subway lines has mixed results in Brooklyn. The New York Public Interest Research Group Straphangers Campaign, which conducted the study, rated all 16 Brooklyn subway lines. They didn't look for litter, instead they examined train seats, floors and even windows for cleanliness. The study found that Brooklyn?s M line topped the list of the dirtiest subways, while the 4 line was named the cleanest.The survey was conducted from September 2005 through January 2006 and results suggest train conditions are getting worse.Related Information NYPIRG's Straphangers Campaign