A young woman pushed a man to his death under an oncoming train at the 40th Street-Lowery Street subway station in Sunnyside, Queens, on Thursday evening, law enforcement authorities said.

The woman got up from her seat, walked behind the man along the platform, mumbling to herself, witnesses told the police, before shoving him into the path of a Flushing-bound No. 7 train just after 8 p.m. Witnesses said the victim did not appear to notice her.

The man, whom the police have not yet identified, was pushed with little time to avoid the hurtling train, or for others to come to his aid, said Paul J. Browne, the Police Department’s chief spokesman. His body remained under the second car of the 11-car train, which officers from the Emergency Services Unit planned to lift using specialized inflatable bags to recover his remains.

“We haven’t determined whether it was random or if there was some connection yet,” Mr. Browne said, “but there was nothing from what the witnesses could see to indicate that they knew each other and he did not, according to the witnesses, appear to realize that she was approaching.”