The House Transportation Committee is debating the future of Amtrak in light of recent incidents, including last month's deadly derailment in Philadelphia.
Members of the National Transportation Safety Board and the Federal Railroad Administration detailed possible causes of the derailment during a hearing Tuesday.
Eight people were killed while traveling between Washington, DC, and New York City.
The NTSB has not ruled out human error in the crash. The train was going 106 miles per hour before the engineer applied the emergency break as the train neared a turn where the speed limit was 50 miles per hour.
"Humans make mistakes. That is fundamental. The engineers are a very good population of people. They are hard-working, try to do the right thing. But they make mistakes because they are humans. That is not criticism. That is just a statement of fact. Humans make mistakes. That is why positive train control is the most important single backup to respond to human error," said NTSB chairman Christopher Hart.
The crash is said to have cost Amtrak more than $9 million. Lawsuits have also been filed by passengers.