(Baltimore, MD)  --  Firefighters are spraying foam on burning train cars that derailed near Baltimore.  Six to eight cars of a CSX freight train leapt off the tracks and caught fire around 2 p.m. in the suburb of Rosedale.  Moments later a loud explosion rocked the area, sending a huge plume of smoke into the sky above downtown Baltimore.  Emergency crews have rescued one person who had reportedly trapped in the derailment.  Hazmat teams are on the scene and the National Transportation Safety Board says it will look into the incident.