US investigators release more details on 2015 Amtrak crash

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NTSB to Release Documents in Philadelphia Amtrak Crash Investigation

NEW YORK (Reuters) -- Federal investigators on Monday released thousands of pages about the fatal derailment of an Amtrak passenger train last year in Philadelphia, but the central mystery of what caused the crash remained unexplained.

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The documents, posted online by the National Transportation Safety Board, include interviews with the train's engineer, Brandon Bostian, who told investigators he had no recollection of the moments before the accident.

An Amtrak regional train headed from Washington, D.C., to New York, went off the tracks on May 12 along a northbound curve in Philadelphia while traveling at more than twice the 50 mile-per-hour (80 kilometer-per-hour) speed limit. Eight people were killed and more than 200 injured in the incident.

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Amtrak train crash, derailment, Philadelphia
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US investigators release more details on 2015 Amtrak crash
Amtrak assistant conductor Brandon Bostian stands by on Aug. 21, 2007 as Sandra Palmer of University City says goodbye to her boyfriend, Clyde Simpson, as he leaves for work in Chicago at the Amtrak station in St. Louis. Bostian was the engineer of the Amtrak train that derailed in Philadelphia. (Huy Richard Mach/St. Louis Post-Dispatch/TNS via Getty Images)
PHILADELPHIA, PA - MAY 13: Investigators and first responders work near the wreckage of an Amtrak passenger train carrying more than 200 passengers from Washington, DC to New York that derailed late last night May 13, 2015 in north Philadelphia, Pennsylvania. At least five people were killed and more than 50 others were injured in the crash. (Photo by Win McNamee/Getty Images)
PHILADELPHIA, PA - MAY 14: Members of the National Transportation Safety Board gather near the site of the Amtrak train derailment May 14, 2015 in Philadelphia, Pennsylvania. Service has been interrupted after an Amtrak train derailed in Philadelphia on Tuesday night killing at least seven people and injured more than 200. (Photo by Mark Wilson/Getty Images)
PHILADELPHIA, PA - MAY 13: Repair crews inspect damages at the site of a train derailment accident May 13, 2015 in Philadelphia, Pennsylvania. Service has been interrupted after an Amtrak train derailed in Philadelphia last night, killing at least seven people and injured more than 200. (Photo by Alex Wong/Getty Images)
Philadelphia Mayor Michael Nutter, center right, hugs Lori Dee Patterson, a nearby resident, after she handed him a cup of coffee after he spoke at a news conference near the scene of a deadly train derailment, Wednesday, May 13, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia on Tuesday night, killing at least six people and injuring dozens more. (AP Photo/Matt Slocum)
In this aerial photo, emergency personnel work at the scene of a deadly train wreck, Wednesday, May 13, 2015, in Philadelphia. Federal investigators arrived Wednesday to determine why an Amtrak train jumped the tracks in a wreck that killed at least six people, and injured dozens. (AP Photo/Patrick Semansky)
PHILADELPHIA, PA - MAY 13: Investigators and first responders work near the wreckage of Amtrak Northeast Regional Train 188, from Washington to New York, that derailed yesterday May 13, 2015 in north Philadelphia, Pennsylvania. At least six people were killed and more than 200 others were injured in the crash. (Photo by Win McNamee/Getty Images)
PHILADELPHIA, PA - MAY 13: In this handout image supplied by NTSB, NTSB member Robert Sumwalt works on the scene of the Amtrak Train #188 derailment on May 13, 2015 in Philadelphia, Pennsylvania. Service has been interrupted after Amtrak train derailed in Philadelphia last night, killing at least seven people and injured more than 200. (Photo by NTSBgov via Getty Images)
National Transportation Safety Board member Robert Sumwalt speaks at a news conference near the scene of a deadly Amtrak train wreck, Wednesday, May 13, 2015, in Philadelphia. Sumwalt said Wednesday that the train was traveling at 106 mph when the engineer hit the brakes Tuesday night. (AP Photo/Matt Slocum)
National Transportation Safety Board lead investigator Robert Sumwalt speaks during a press conference regarding the wreckage of the derailed Amtrak Northeast Regional Train in Philadelphia, Pennsylvania, on May 13, 2015. The engineer of a US passenger train traveling at more than twice the approved limit slammed on the emergency brakes just before it derailed in Philadelphia, leaving at least seven people dead, investigators said. AFP PHOTO / ANDREW CABALLERO-REYNOLDS (Photo credit should read Andrew Caballero-Reynolds/AFP/Getty Images)
PHILADELPHIA, PA - MAY 13: Investigators and first responders work near the wreckage of Amtrak Northeast Regional Train 188, from Washington to New York, that derailed yesterday May 13, 2015 in north Philadelphia, Pennsylvania. At least six people were killed and more than 200 others were injured in the crash. (Photo by Win McNamee/Getty Images)
PHILADELPHIA, PA - MAY 13: Investigators and first responders work near the wreckage of an Amtrak passenger train carrying more than 200 passengers from Washington, DC to New York that derailed late last night May 13, 2015 in north Philadelphia, Pennsylvania. At least five people were killed and more than 50 others were injured in the crash. (Photo by Win McNamee/Getty Images)
Rescuers work around derailed carriages of an Amtrak train in Philadelphia, Pennsylvania, on May 13, 2015. Rescuers on May 13 combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. AFP PHOTO/JEWEL SAMAD (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
Emergency personnel walk near the scene of a deadly train wreck, Wednesday, May 13, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia on Tuesday night. (AP Photo/Mel Evans)
Emergency personnel work at the scene of a deadly train derailment, Wednesday, May 13, 2015, in Philadelphia. The Amtrak train, headed to New York City, derailed and crashed in Philadelphia on Tuesday night, killing at least six people and injuring dozens of others. (AP Photo/Patrick Semansky)
Rescuers stand near a derailed carriage of an Amtrak train in Philadelphia, Pennsylvania, on May 13, 2015. Rescuers on May 13 combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. AFP PHOTO/JEWEL SAMAD (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
Rescuers work around derailed carriages of an Amtrak train in Philadelphia, Pennsylvania, on May 13, 2015. Rescuers on May 13 combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. AFP PHOTO/JEWEL SAMAD (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
Passengers queue infront of ticketing counters at Union Station on May 13, 2015 in Washington, DC. Rescuers on Wednesday combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. Witnesses said the front of Amtrak Train 188, heading from Washington DC to New York, shook as it went into a turn and crashed at about 9:30 pm on Tuesday (0130 GMT Wednesday). AFP PHOTO/MANDEL NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)
Information screen showing cancelled train services at the Union Station on May 13, 2015 in Washington, DC. Service has been interrupted after Amtrak train derailed in Philadelphia last night, killing at least six people and injured more than 140. (Photo by Alex Wong/Getty Images)
Injured Amtrak passengers that were bused from to New York from Philadelphia wait at Penn Station May 13, 2015 in New York. Rescuers on Wednesday combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Passengers injured in an Amtrak train derailment who were bused from to New York from Philadelphia, walk through Penn Station May 13, 2015 in New York. Rescuers on Wednesday combed through the mangled wreckage of a derailed train in Philadelphia after an accident that left at least six dead, as the difficult search for possible survivors continued. AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Carolan Berkeley (L), who had an Amtrak ticket to go from New York to Washington D.C., waits for a bus from New York to Washington D.C. on May 13, 2015 in New York City. An Amtrak train crash in Philadelphia last night has forced train service to be suspended between New York, Philadelphia and Washington D.C., causing commuters to use NJ Transit, flights and bus services. The crash killed at least six people and injured dozens more. (Photo by Andrew Burton/Getty Images)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and tipped in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
A crime scene investigator looks inside a train car after a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
An Amtrak train crashed Tuesday, May 12, 2015, near Philadelphia. Train 188 was traveling from Washington to New York City. (AP Photo/Paul Cheung)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel help a passenger at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help a passenger at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and tipped over in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and tipped over in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help a passenger at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help passengers at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and tipped over in Philadelphia. (AP Photo/ Joseph Kaczmarek)
A passenger from an Amtrak train that crashed is helped Tuesday, May 12, 2015, in Philadelphia. Train 188 was traveling from Washington to New York City. (AP Photo/Paul Cheung)
Passengers of an Amtrak train that crashed gather Tuesday, May 12, 2015, near Philadelphia. Train 188 was traveling from Washington to New York City. (AP Photo/Paul Cheung)
This photo provided by WCAU NBC10 shows an Amtrak train that crashed Tuesday, May 12, 2015, near Philadelphia. Train 188 was traveling from Washington to New York City. (WCAU NBC10 via AP) MANDATORY CREDIT
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
A passenger is carried following an Amtrak train crash Tuesday, May 12, 2015, near Philadelphia. Train 188 was traveling from Washington to New York City. (AP Photo/Paul Cheung)
My train crashed
Emergency personnel transport a person at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Matt Slocum)
This photo provided by WCAU NBC10 shows an Amtrak train that crashed Tuesday, May 12, 2015, in Philadelphia. Train 188 was traveling from Washington to New York City. (WCAU NBC10 via AP) MANDATORY CREDIT
Officers gather at the scene of a train crash Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Paul Cheung)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Matt Slocum)
Emergency personal transport a victim at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Matt Slocum)
Officers gather at the scene of a train crash Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Paul Cheung)
Emergency personnel transport a person at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Matt Slocum)
http://t.co/GvooK8lq58
Im on @Amtrak train that just crashed. Im ok. Helping others. Pray for those injured.
@Amtrak @msnbc @NBCNews pray for these passengers. http://t.co/mksZNy7eqo
Amtrak Northeast Regional crashes, was en route to NYC http://t.co/Faz7G48nbf http://t.co/XoLgkdBnHY
#BREAKING - At least 50 hurt in Amtrak derailment in Philly. Live video here: http://t.co/btWPTtn6HM
Multiple injuries reported after Amtrak train #188 from DC to NYC derails in #Philadelphia. Several cars overturned. http://t.co/mHFbLOv3to
Lot's of injuries at the #amtrak derailment. #Pray http://t.co/DADBYAqojg
#Amtrak crash: 50+ people injured http://t.co/IpNb3bkIzp
Amtrak train derailment. http://t.co/fAwU7MFrZC
Live picture of the triage center at 2400 Wheatsheaf for the Amtrak derailment. http://t.co/JL2XuYZfob
EMT helping survivors taking them to the hospital #amtrak #philly http://t.co/SfyFJJjNqO
FBI: nothing indicates that #Amtrak derailment linked to terrorist attack http://t.co/P2as9zyu2S
Video I took moments after crash. People trying to open the door and get off the train. http://t.co/fJ2bxXfmhG
Photos from tonight's Amtrak derailment in Port Richmond http://t.co/DIv1xCk5YU http://t.co/ZzJqcOYPGU
As Philadelphia Mayor Michael Nutter, left, and Pennsylvania Gov. Tom Wolf, right, listen Amtrak CEO, Joseph Boardman expresses his sorrow near the site of a deadly train derailment Thursday, May 14, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia on Tuesday night killing eight people and and sending more than 200 passengers and crew to area hospitals. Investigators have said the Amtrak passenger train was going more than twice the allowed speed when it shot off a sharp curve. (AP Photo/Mel Evans)
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The documents represent every fact that the various agencies involved in the investigation, including the NTSB, Amtrak, local emergency responders and rail worker unions, have agreed upon.

The NTSB has previously said Bostian was not talking or texting on his phone at the time of the accident. His lawyer has said Bostian had turned off his phone, as required by federal regulations.

The documents released on Monday contain no "smoking guns," according to an NTSB official. Their release marks the end of the agency's fact-finding phase.

Investigators are now focused on identifying the probable cause of the crash. That analysis will be included in a final report that will likely be reviewed by the NTSB in the spring.

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