Palmetto Train 89 was headed from New York to Savannah, Ga., when it struck a backhoe on the tracks, causing the lead engine to derail, Amtrak said in a statement. It was carrying seven crew members and about 341 passengers, some of whom were being treated for injuries, Amtrak said.
Local police told affiliate NBC10 that two people died and at least one was hurt.
The Chester police and fire departments could not be reached for comment.
Authorities said the backhoe belonged to Amtrak.
Shortly after 10 a.m. Sunday, the Federal Railroad Administration said investigators had arrived at the scene. The National Transportation Safety Board was sending a team of investigators to join them.
FRA investigators have arrived on scene of Amtrak incident near Chester, Pa.