Tonight at 22:22hrs Station 50 was dispatched to the 1800 Block of South Church Street for a Tractor Trailer Fire. Engine 52 with 5 members and Engine 53 with 5 members quickly marked en route. Units arrived on scene and found heavy fire in the engine compartment and cab of a single tractor trailer. Both Engine company crews made an aggressive attack on the fire. Fire was marked under control within 7 minutes of initial dispatch. Extensions to one vehicle beside the tractor trailer, no injuries reported. Scene has been turned over to Smithfield Police Department. Unknown cause of the fire at this time.