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.
