Abstract: A rack and pinion gear train actuator for a pintle valve. A motor shaft has a pinion gear that engages a large reduction gear having an integral hub gear. The hub gear is a planet gear for a ring gear segment that pivots on a shaft and includes a pinion gear segment that engages a linear rack. The rack is attached to a valve pintle shaft, causing the valve to be opened and closed in response to rotation of the motor shaft. The pintle shaft, return spring, rack, and gears are all assemblable by slip fit. The actuator has a high actuation force, a fast response time, and compact design by virtue of a rack and internal gearing. The stroke of the rack may be changed for use with pintle valves having differing strokes by varying the angle through which the motor operates.