A man who punched a schoolgirl after her backpack bumped him on a SEPTA trolley in January pleaded guilty to simple assault today in Philadelphia Municipal Court, earning himself 9½-23 months in prison.

Damon Oliver, 40, a former facility caretaker in the city's parks and recreation department, was riding the crowded Route 15 trolley when he grew enraged and pummeled the girl, 17, who was on her way to Bodine High School for International Affairs in Northern Liberties, where she was a junior. The girl suffered a broken nose and black eye in the assault, which was captured by SEPTA's surveillance cameras as well as at least one bystander's smartphone.

The teen and her family have since moved to Montgomery County, and she enrolled in a suburban school.