CHESTER, Pa. (AP) — An Amtrak train struck a piece of heavy equipment just south of Philadelphia on Sunday, causing a derailment that killed two Amtrak workers and sent more than 30 passengers to hospitals, authorities said.

Train 89 was heading from New York to Savannah, Georgia, at about 8 a.m. when it hit the equipment that was on the track in Chester, about 15 miles outside Philadelphia, officials said. The impact derailed the lead engine of the train that was carrying more than 300 passengers and seven crew members.

Chester Fire Commissioner Travis Thomas said two people were killed. A National Transportation Safety Board official confirmed that one was the operator of the equipment. U.S. Sen. Chuck Schumer, D-N.Y., said Amtrak board Chairman Anthony Coscia told him the other person killed was a supervisor and both were Amtrak employees.

 TSB investigator Ryan Frigo said at an evening news conference that the event data recorder and forward-facing and inward-facing video from the locomotive have been recovered.He said the locomotive engineer was among those taken to hospitals. Officials said earlier that none of the injuries was deemed life-threatening.

Schumer said it's unclear whether the equipment was being used for regular maintenance, which usually is scheduled on Sunday mornings because there are fewer trains on the tracks, or whether it was clearing debris from high winds in the area overnight. But he said Amtrak has "a 20-step protocol" for having such equipment, described by Amtrak as a backhoe, on the track, and no trains are supposed to go on a track when equipment is present.

"Clearly this seems very likely to be human error," Schumer said, calling for Amtrak to review its processes. "There is virtually no excuse for a backhoe to be on an active track."