MBTA 5 hours ago MBTA official talks about investigation into Green Line derailment in Cambridge US & World Videos 1:35 Political candidate signs vandalized in Tyngsborough 1:26 Escaped inmate found in Foxborough, back in custody 0:17 Police investigating reported stabbing in Dorchester 4:31 Several injuries reported after Green Line derailment in Cambridge 2:38 Mom alleges teacher beat her son, who has autism, at Dorchester school