At 1:30 the department was dispatched to the PA Turnpike west bound mile post 300.5 for a tractor trailer fire. Engine 69-5 and Chief 69 went enroute and were advised the vehicle was in the pull off area and the rear brakes were on fire spreading to the trailer. Upon arrival Chief 69 advised Engine 69-5 to pull both bumper lines. The fire was placed under control at 1:50. The crew stood by and checked the rest of the trailer for extension. All units went available at 2:17.