Keywords: June 22, 2009 WMATA Collision - NTSB accident photo 422865.jpg en NTSB file ID 422865 Original caption NTSB photo of impedance bond http //www ntsb gov/Dockets/RailRoad/DCA09MR007/default htm http //www ntsb gov/Dockets/RailRoad/DCA09MR007/422865 pdf NTSB Original work of US Federal Government PD-USGov June 22 2009 Washington Metro train collision |