Authorities now say that seven people are confirmed dead in the collision of two Metro trains in Washington D.C. yesterday afternoon. At least 70 others were severely injured and crews are still removing debris and looking for possible victims. Two sets of six-car trains collided on the Red Line near the Fort Totten station; Metro's general manager explained yesterday, "At 5:02 p.m., one train was stopped waiting to get the order to pass, because the train stopped at a platform. The next train came up behind it, and for reasons we do not know, plodded into the back of that train - the operator of that train was the one who lost her life." The first car of the second train was going so fast that it was lodged on top of the first train.

While the investigation is just beginning, speculation is that system failures and operator error may have caused the collision; the Washington Post reports:

Metro was designed with a fail-safe computerized signal system that is supposed to prevent trains from colliding. The agency's trains are run by onboard computers that control speed and braking. Another electronic system detects the position of trains to maintain a safe distance between them. If they get too close, the computers automatically apply the brakes, stopping the trains.

These systems were supposed to make yesterday's crash impossible.

This morning, during a press conference, D.C. Police Chief Cathy Lanier said that the city had not yet notified the next of kin of victims, because they were still trying to establish their identities. So far, only train operator Jeannie McMillan has been identified as one of the fatalities. DCist also reports, "NTSB spokesperson Debbie Hersman said this morning that the struck train should have nine data recorders on it, as it was composed mostly of newer model rail cars, but they do not expect to get good data from the striking train, as it was made up of older, 1000-series cars."