At 1549 hours after running back to back structure fires on Spring Twp, the crew jumped from the Rescue to the Engine and responded to the area of Rt 61 & Orchard @ the Ontelaunee Orchards for a reported tractor trailer fire. Captain 37 arrived on the scene right away and confirmed a working fire on a trailer that was being towed by a dump truck. Engine 11-1 arrived on the scene and the crew deployed two attack lines and went in service. The fire was quickly extinguished. The crew cleaned up their equipment and returned to station.