00:22it's June 22nd 2009 afternoon rush hours in full swing as people make their way
00:29home little do they know is some people would never reach their final destinations at around 4 50 p.m.
00:38on the Washington Metro Area Transit Authority red line train 214 is making its way to Shady Grove
00:45with Breda 3000 series cars 30 36 30 37 32 57 32 56 and CAF 5000 series cars 50 67
00:58and
00:5850 66 at 4 57 p.m. Washington Metro train 112 left the Tacoma station following 214 with Roar 1000
01:10series
01:11cars 1079 1078 1071 1070 1130 and 1131 the cars are equipped with onboard systems called automatic
01:22train operation and automatic train control which allows for autonomous train operation with little
01:29human intervention it uses track circuits to determine which sections of track trains are
01:34occupying it however there's a problem with the circuit that nobody knows train 214 suddenly
01:42comes to a stop between Tacoma and Fort Totten but 112 however is still traveling behind at 55 miles an
01:50hour until it rounds a blind curve and disaster struck
02:06there is late word tonight on what has been a deadly Metro train crash in Washington DC emergency
02:13crews are on the scene of what's being described as a mass casualty event officials say a six car train
02:18crashed into another near the Washington Maryland border it happened during the height of Monday
02:22evening that death toll did rise to nine overnight after search crews with cadaver dogs found three
02:28more bodies in the wreckage of the trains behind me the second train the first car was just absolutely
02:34shredded second train or the second car the the seats were out the window it was awful train 112 plows
02:43into the rear
02:44of 214 car 1079 telescope over the rear car of the stationary train trapping many passengers who
02:53required rescue by emergency workers using ladders to access such telescoping hadn't been a thing on
03:00railroads since the early 20th century and the era of wooden coaches and steam locomotives nearly 90 years prior
03:09Dennis Augsby and Martin Griffith two United States Army soldiers who are in the lead train and were
03:16uninjured from the collision helped passengers most of whom appearing to have minor injuries evacuate from
03:21the train the two then noticed that six to eight people from the other train had been ejected by the
03:27force of the collision and were more seriously injured one person from the overtaking train had been thrown
03:33onto the roof of the stationary train and suffered a severe head wound the soldiers gave first aid to
03:40more the seriously injured people until help arrived and informed responding emergency personnel that the
03:46rails were still powered by their third rail and needed to be shut off immediately following the
03:53collision firefighters and paramedics from the District of Columbia fire and emergency medical
03:59services were dispatched to the scene and arrived at the location of the collision soon after DC fire chief
04:07Dennis Rubin stated that the initial 911 calls made the incident seem rather small like a light tap of a
04:15collision but after firefighters arrived on the scene they were overwhelmed by a scene of destruction within
04:23two hours more than 200 firefighters were on scene in response to the three alarm incident
04:29rescuers worked throughout the night using cranes and heavy rescue equipment to free trap passengers and search for bodies
04:41nine people lost their lives including the operator of train 112 and approximately 80 more suffered varying degrees of injuries
04:52an NTSB investigation found out that the ATC track circuit on the section of the track had gone faulty
04:59and would not register the location of trains accurately you see after a June 17th replacement of the track circuit
05:07component
05:08the track circuit have been suffering from parasitic oscillations which is an undesirable repeating of
05:15of cylindrical variation in voltage or current in electrical circuit resulting in a periodic waveform
05:22it is often caused by feedback in an amplifying device the problem usually occurs notably in RF audio
05:30and other electronic amplifiers as well as in digital signal processing this left the track circuit unable to
05:38reliably report when the track when a certain stretch of track was occupied by another train
05:44the struck train came to a stop because of traffic ahead and because the entire train was within the faulty
05:51circuit
05:51it became virtually invisible to the automatic train control system the train behind it was therefore commanded to
05:58proceed to 55 miles an hour the operator of the striking train applied the emergency brakes after the
06:06stop train came into full view but there was little to no time in order to prevent the collision
06:12a series of near misses in 2005 with similar circumstances in the tunnel between foggy bottom and roslin stations
06:21led to a new test procedure which would have identified the faulty circuit
06:25however by 2009 Metro engineers were unaware of this incident or the test developed to detect the failure
06:33it was a warning of things to come that was never acknowledged
06:38the NTSB also found that the operator's decision to operate 214 in manual mode during the evening rush period
06:47was in violation of Metro Rail rules but then again the track circuit was failing to detect trains anyway
06:54regardless of whether they were operating in manual or automatic mode
06:59the NTSB then recommended WMTA to establish periodic inspection and maintenance procedures to examine
07:07all audio frequency track circuit modules within the Metro Rail system to identify and remove from service
07:14any modules that exhibit pulse type parasitic oscillation that could be faulty
07:19in the end cars 1078 5066 and 5067 were retired after the collision and used as a source of spare
07:30parts
07:30until the retirement of the 5000 series rail cars in 2018 where they were eventually scrapped
07:38WMAT announced the policy of no longer placing 1000 series trains at the end of the train concepts
07:46to prevent the telescope from the event of collision as they were the weakest of our structure in the future
07:52all 1000 series cars were put in the middle of trainsets and served another 8 years until retirement in 2017
08:03more than 10 years have passed since the crash and hopefully safety oversights like this one that caused this accident
08:10don't ever happen in the future
08:32never happen in the future
08:42the mundane errors
08:47the 되뇨
08:48addresses
