injuring others as cars of one train jackknifed into the air and fell atop the other. The mayor of Washington, DC, confirmed the four dead. Mayor Adrian Fenty says that would make it the deadliest accident in the history of the Metro train system. According to an emergency rescue official, two other people have life-threatening injuries, and 70 people in all were hurt. Rescue workers propped steel ladders up to the upper train cars to help survivors escape. Seats from the smashed cars ...