The Philadelphia derailed train that killed at least seven people, was travelling at twice the speed limit, safety experts say.
The speed was recorded in the so-called black box recovered from the wreckage.
The derailment left more 200 people injured and the search for victims and survivors goes on.
The train's driver and conductor were both injured in the crash.
The driver, who has not been identified, has declined to give a statement to police, according to the Philadelphia Inquirer newspaper.
As emergency crews continued to dig through the wreckage, lawmakers in Washington debated the future of Amtrak's budget, with one spending committee voting to slash their budget by almost a fifth.
"We are divesting from America," accused one member of Congress.
"Don't use this tragedy in that way," another Congressman responded angrily.
Congress has only 18 more days before federal funding for transportation infrastructure expires, but the funding is likely to be temporarily extended.
Any transportation bill would need to be voted on by the entire Congress, and signed by the President before becoming law.
Amtrak is a national publicly funded rail service, serving tens of millions of people every year.
