The first of the victims of the Philadelphia railway crash has been laid to rest as investigators continue to probe why the train was travelling faster than 100mph.
US Naval Academy midshipman Justin Zemser was one of eight people killed as the seven-carriage train sped into a curve and derailed on Tuesday night.
His commanding officer Captain Brandy Soublet said he was "a phenomenal young man", adding he "just had this quiet strength about him".
Capt Soublet spoke outside the Boulevard-Riverside-Hewlett Chapel on Long Island, New York, where the funeral was held.
The 20-year-old cadet was travelling from the academy in Annapolis, Maryland, to his home in New York City when he was killed.
The Naval Academy said Mr Zemser was a talented and highly respected young man with a bright future.
He was a member of the navy sprint football team, the Jewish Midshipman Club and the Semper Fi Society, a Marine Corps club.
The last wrecked carriages from the derailment were earlier removed from the scene and taken to an Amtrak facility in Delaware for further examination.
The National Transportation Safety Board (NTSB) released the site back to operators yesterday and Amtrak is working to restore the Northeast Corridor route between New York City and Philadelphia.
The railroad is making repairs to damaged tracks, signals and overhead power lines before resuming limited service between Philadelphia and New York on Monday, with full service expected the following day.
The NTSB said that as the train approached the curve it accelerated to 106mph, more than twice the speed limit for that section of track.
Investigators are trying to determine if engineer Brandon Bostian manually increased speed on the train as it accelerated for a full minute before it went off the tracks, injuring more than 200 people.
NTSB i nvestigators have found no problems with the track, signals or locomotive, and the train, on a route from Washington to New York City, was on time as it left the station in Philadelphia a few minutes before the crash.
Investigators want to know why the train was going so fast, but Mr Bostian refused to talk to police on Wednesday.
The engineer has reportedly agreed to be interviewed by the NTSB and the meeting will take place in the next few days.
Separately, the Philadelphia district attorney's office said it was investigating and will decide whether to bring charges.
Amtrak president and chief executive said the national passenger railway takes full responsibility for the crash.
Joseph Boardman said in a letter on Amtrak's official blog that it is co-operating fully in the investigation.
"With truly heavy hearts, we mourn those who died. Their loss leaves holes in the lives of their families and communities," Mr Boardman wrote. "Amtrak takes full responsibility and deeply apologises for our role in this tragic event."