A former city maintenance worker pleaded guilty Tuesday to assaulting a 17-year-old girl on a SEPTA trolley two months ago.

The assault, which was captured on camera, occurred while the victim rode a Route 15 trolley on her way to class at Bodine High School on Jan. 21. Police said Damon Oliver, 40, was angered when the girl's backpack hit him, and responded by beating her.

Oliver was sentenced to 91/2 to 23 months in prison by a Philadelphia Common Pleas Court Judge Glynnis Hill. Two other lesser charges were dropped.

Oliver, who was hired by the city in 2008 and worked in the city's Parks & Recreation Department, was suspended from his job after the arrest and later dismissed.

The North Philadelphia man was convicted of aggravated assault in 1995 and pleaded guilty to simple assault in 2003 and 2006, court records showed. - Matt Gelb