201106 – Szacsvay – Washington Metro Train Crash

At 4:58 pm on Monday, June 22nd, 2009, in the middle of the afternoon rush hour, approaching Fort Totten station, Washington Metropolitan Area Transit Authority (WMATA) Metrorail train 112 ran into the rear of train 214 at close to line speed.

The impact caused the rear car of train 214 to telescope into the lead car of train 112, resulting in the death of nine people on board train112, including the train operator (driver). 52 people were transported to local hospitals, and a further 28 people with minor injuries were treated at the site and allowed to home.

Initial investigations by the National Transportation Safety Bureau (NTSB) focussed on human error and the possibility that the operator of train 112 may have been using her mobile phone at the time of the crash. As the investigation progressed it became clear that the crash was wholly attributable to the unsafe failure of a track circuit to detect train 214, and that this failure mode was far from being a one-off incident. The accident was largely attributable to failures of the signalling equipment and by the signalling discipline.

This paper describes the history of an unsafe failure mode dating back over 20 years, and the equally long chain of events and actions which not only failed to prevent the accident, but also made it almost inevitable that something like this would eventually happen.