A safety valve system includes a safety valve having an actuator and a line connected to the actuator. The safety valve is operable by opening the line in the well, with the line being free of any connection to a surface control system. Another safety valve system includes multiple safety valves.Safety Valves An actuator of each safety valve is connected to an actuator of another safety valve via a line. A biasing force in each of the actuators is operative to close the respective one of the safety valves in response to opening of the line. The biasing force is produced at least in part by hydrostatic pressure in a well.  A safety valve system for use in a subterranean well,API Cast Steel Valves comprising: at least a first safety valve having an actuator; and a line connected to the actuator, the line extending through a device operative to open the line,PLUG VALVES the first safety valve being operable by opening the line, and the line being free of any fluid communication with a surface control system. In carrying out the principles of the present invention, a safety valve system is provided which solves at least one problem in the art. One example is described below in which hydrostatic pressure is used to produce biasing forces in actuator(s) of one or more safety valves. Another example is described below in which the actuator is connected to a line containing fluid pressurized above hydrostatic pressure, so that opening of the line permits the actuator to close the safety valve. In one aspect of the invention, a safety valve system for use in a subterranean well includes at least one safety valve having an actuator. A line is connected to the actuator. The safety valve is operable by opening the line in the well, with the line being free of any connection to a surface control system. In another aspect of the invention, a safety valve system is provided which includes multiple safety valves. An actuator of each safety valve is connected to an actuator of another safety valve via a line. A biasing force in each of the actuators is operative to close the respective one of the safety valves in response to opening of the line. The biasing force is produced at least in part by hydrostatic pressure in a well. In yet another aspect of the invention, a method of operating a safety valve system in a subterranean well is provided. The method includes the steps of: installing in the well at least one safety valve having an actuator; and the installing step including connecting a line to the actuator without connecting the line to a surface control system. In a further aspect of the invention, a method of operating a safety valve system is provided. The method includes the steps of: connecting actuators of multiple safety valves to each other with a line, and installing the safety valves in a well. Hydrostatic pressure in the well produces a biasing force in each of the actuators, so that opening of the line in the well is operative to permit the biasing forces to close the respective safety valves.

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