Abstract: A system and method for regulating the speed of a steam turbine by operating a steam valve rack assembly to adjust the flow of steam to the turbine by controlling the position of the turbine valve rack actuator in response to high pressure oil fed, reacting to signals from a speed control system, through a proportional valve to the valve rack actuator. High pressure oil is fed to the proportional valve from a hydraulic oil accumulator, charged with an inert gas, in which high pressure oil is stored. A source of low pressure oil directed to a pressure intensifying device increases the oil pressure to a high pressure and circulates the high pressure oil to the hydraulic oil accumulator and the proportional valve to stroke the turbine valve rack actuator in response to signals from the speed control system. The system further includes an emergency stop valve system which operates to close the turbine valve rack assembly very rapidly in the event of a serious turbine condition.