At 16:02 hours the high hazard box was struck for the Main Line Berywn Apartments in Chester County. The box called for Station 2, Station 3, Ladder and Engine 15 from Delco. Ladder-15 hit the street with a crew of 4 immediately. While enroute incident commander Assistant 2A (Brazunas, B) advised this was a working roof fire and Ladder-15 would need to go to work upon arrival. Crews led by 15-9C (Maguire, M) setup the main and went to work opening up the roof of this multi-story multi occupancy structure. Squad-15, 15-1 and Rescue-15 arrived and assisted with searches and opening up. A number of residents were assisted outside while additional manpower extinguished the fire. Crews were clear the scene by 17:45 hours.