Fairfax County police say a 13-year-old girl walking on a bridge was struck and killed by a commuter train in the Virginia suburbs of Washington, D.C. The department said on Twitter that the girl was hiking with relatives Wednesday afternoon and was walking on Bull Run Bridge when a train approached. Police say two relatives walking with her on the bridge were able to get out of the way. Investigators say the Virginia Railway Express train hit the girl. There were no reports of injuries among passengers or the train’s crew. Late Tuesday, two CSX conductors who got out of their freight train to check on an alert that there was a problem with its wheels were struck and killed by a passenger train near Washington’s Union Station.