This morning, the township companies responded to I81 NB MM53.3 for a tractor trailer fire which was updated to include grass along the berm. Chief 133 arrived with no tractor trailer involved. E33 placed the booster line in service upon arrival. E31 assisted at the scene. Both units shown in a blocking formation to protect responders. Brush 33 responded to a location off the Interstate in case the fire got off the Interstate right of way but was not needed. Units operated about 20 mins.