PHILADELPHIA - The National Transportation Safety Board has wrapped up its onsite investigation of the Amtrak Train 188 derailment in Philadelphia, and the last of the wreckage has been cleared from the tracks.

The NTSB says engineer Brandon Bostian told investigators he last remembered ringing the train's bell while passing by the North Philadelphia station Tuesday night. NTSB member Robert Sumwalt says, "He has no recollection of anything past that."

Sumwalt also says that an assistant conductor in the cafe car of the Amtrak train said she heard Bostian talking to a SEPTA train engineer who said he'd been "hit by a rock or shot at." She says she thought she heard the Bostian say his train had also been struck.

Sumwalt says his team has "seen damage to the left hand lower portion of the Amtrak windshield" and has asked the FBI to look at it.

As the investigation continues, there are now calls from lawmakers for better technology to prevent similar deadly accidents.

Sen. Cory Booker says existent technology could be used to prevent trains from speeding or suddenly surging.

"Years ago we had the technology to really control our trains with a lot greater safety," the senator says. "The big challenge is implementing it. It takes a significant amount of resources."

This week Congress voted to cut Amtrak's funding.

Eight people were killed and more than 200 injured when the train derailed Tuesday night. It was going over 100 mph on a curve designed to be traveled at half that speed.

The NTSB has found the train increased its speed by 20 mph in just 30 seconds before the crash

Amtrak service between New York and Philadelphia is expected to resume fully by next week. Repairs are currently being made to the tracks. New Jersey Transit is honoring Amtrak tickets between Trenton and New York for the time being.

The Associated Press wire services contributed to this report.