DC Metro update

A commuter train crashed into the rear end of another in Washington D.C. killing nine people and injuring more than 70, officials reported.  Around 20 people sustained life-threatening injuries.  The rush hour accident was the worst in Metrorail’s 33-year history. 
 The collision was on Metro’s red line, the busiest line in the system.  The first train stopped on the tracks near the Fort Totten station, waiting for a train ahead to clear its way.  Another train came from behind and crashed into its rear, sending the second train on top of the first.
 Investigations will likely focus on Metrorail’s failed computerized signal system, which is supposed to prevent trains from coming too close to each other.