A Manhattan transit worker was attacked Friday morning by a passerby who hurled an orange at her stomach, police said. The unusual assault happened 7:30 a.m. on Lexington Ave. near E. 99th St. Police said the suspect approached the transit worker, who was in a booth. She stepped outside to ask how she could help, at which point the suspect threw the fruit at her. The attacker, a woman in her 50s, ran off and is being sought. The 32-year-old victim was taken by medics to Mount Sinai Hospital with a minor bruise.