Multi-motion fail-safe operating gate valve

An actuator for use with a valve, comprising:

• a first drive mechanism for applying a first driving force to a valve stem, the first drive mechanism arranged within an actuator housing and configured to couple to the valve stem at an interface;
• a second drive mechanism for applying a second driving force to the valve stem, the second drive mechanism arranged, at least partially, within the actuator housing and configured to couple to the valve stem at a second interface;
• and
• a retention member associated with the second drive mechanism, the retention mechanism releasably maintaining the second drive mechanism at a first position, where the second driving force acts on the retention member, and enabling movement to a second position, where the second driving force acts on the valve stem;
• at least one of the first drive mechanism and the second drive mechanism is an electric motor;
• the interface comprises splines of the electric motor interacting with splines of the valve stem;
• and the retention member comprises:
• a piston;
• a cylinder, the cylinder receiving the piston and having an inlet axially lower than a piston head;
• and a valve associated with the cylinder, the valve blocking a working fluid at least one of entering or exiting the cylinder.