The pedestrian was on a bridge in a remote area over the Quinnipiac River at 4:44 a.m. when he or she was struck, police said.
New Haven Sgt. Peter Moller told the New Haven Register that the Amtrak employee was “adamant” about what he saw.
Police, firefighters and emergency crews checked the area around with track but did not find anyone, police told the Hartford Courannt.
The Coast Guard confirmed that they are helping with the search.