On this day, June 22, 2009, two Metrorail trains collided between Fort Totten and Takoma

[mahatmakanejeeves]

June 2009 Washington Metro train collision



NTSB photo of accident scene

Details
Date: June 22, 2009; 17:02 EDT (21:02 UTC)
Location: Between Takoma and Fort Totten, Northeast, Washington, D.C.
Coordinates: 38°57?37?N 77°0?21?W
Cause: Track circuit malfunction

Statistics
Trains: 2 (2 six-car trains)
Deaths: 9 (including a train operator)
Injured: Approximately 80

During the afternoon rush hour of June 22, 2009, a subway train-on-train collision occurred between two southbound Red Line Washington Metro trains in Northeast, Washington, D.C., United States. A moving train collided with a train stopped ahead of it; the train operator along with eight passengers died, and 80 people were injured, making it the deadliest crash in the history of the Washington Metro.

The National Transportation Safety Board (NTSB) investigation found that after a June 17 replacement of a track circuit component at what became the site of the June 22 collision, the track circuit had been suffering from parasitic oscillations which left it unable to reliably report when that stretch of track was occupied by a train. The struck train came to a stop because of traffic ahead. Because the entire train was within the faulty circuit, it became invisible to the Automatic Train Control (ATC) system. The train behind it was therefore commanded to proceed at 55 mph (89 km/h). The operator of the striking train applied the emergency brake after the stopped train came into full view, but there was not enough time to prevent the collision, which occurred at approximately 49 mph (79 km/h).

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Collision



Aerial view of emergency responders at the crash



NTSB and Recovery team working in the night following the collision.

At approximately 4:57 pm EDT (20:57 UTC) on Monday, June 22, 2009, Washington Metro Train 112, bound from Glenmont to Shady Grove, left the Takoma station. Minutes later at 5:02 pm, Train 112 rear-ended Train 214, which was stopped between the Takoma and Fort Totten stations while waiting for another train to leave the Fort Totten station. Nine people died, including the operator in the lead car of the moving train, Jeanice McMillan, 42, of Springfield, Virginia; at least 80 people were injured. The death toll makes the crash the deadliest in Metro history.

The NTSB found that Train 214 had come to a stop entirely within the faulty circuit B2-304, making it effectively invisible to the automatic train control (ATC) system. Other trains had received speed commands of 0 when traveling through this circuit, but had enough forward momentum to make it to the next circuit and resume detection and receipt of speed commands from the ATC system. Train 214 was going slower than normal because it was being driven in manual mode by its operator, and it came to a stop while remaining on circuit B2-304 and was therefore invisible. Train 112 behind it was given full speed (55 mph [89 km/h]) commands by the ATC to proceed on the track. The investigation found that the emergency brakes had been applied by the operator of train 112 when train 214 came into view but it was too late to avert the collision, which occurred with a speed of about 49 mph (79 km/h).

A series of almost-collisions in 2005 in similar circumstances in the tunnel between Foggy Bottom and Rosslyn stations led to a new test procedure which would have identified the faulty circuit after installation. However, by 2009, Metro engineers were unaware of this incident or the tests developed to detect the failure condition.

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