A retort agitation system (100) for thermal processing of products includes product carriers (102a) and (102b) mounted on a low friction support system (104) for reciprocal movement of the carriers along the interior of a retort. The product carriers are driven in reciprocating motion by a drive actuator system (106) that can be positioned between the carriers (102a) and (102b) or endwise of the two carriers (102a) and (102b). A drive actuator system (106) is linked to the carriers to cause the carriers to move along opposite reciprocating paths lengthwise of the retort. Reaction actuators (108) act on the carriers in opposition to the drive actuator system (106) to apply forces on the carriers for accelerating the carriers along the reciprocating paths of travel when such carriers reach the distal and proximal ends of the reciprocating travel paths.
