Abstract: A chassis having a walking beam undercarriage suspends a carrier in an adjustable manner. The carrier is confined for vertical travel by chassis mounted guides and serves to carry a series of liner members defining multiple burning chambers. Each chamber is served by a low pressure oil burner and exhausts a heat flow downwardly against the passing ground surface. The liner members are detachably mounted by knock-out pins for purposes of periodic servicing the carrier. Repositionable wheel assemblies on the walking beam undercarriage permit travel of the chassis in one direction during operation and lengthwise travel for passage over roadways.