That's a little one there. I've seen plenty of dual axle rigs and some 3 axle. Many are lined with fire brick and have propane burners attached. The locals around here say you have to use red oak. The best BBQer I know here, and he makes many huge events as a caterer and is paid handsomely, throws Kingsford charcoal in the pit bag and all, lights it and then adds the oak bark at cooking time.