A steam generating boiler system, comprising: a boiler having a furnace, a superheater section and a reheater section coupled to the superheater section, wherein the boiler is a once-through boiler; and a controller communicatively coupled to the boiler to control operation of the boiler, the controller characterised by being communicatively connected to the reheater section to receive a first signal, other than a signal corresponding to a desired superheater spray setpoint, that is indicative of a desired value of a reheater steam temperature control or manipulated variable used in the reheater section to control steam temperature at an output of the reheater section, and to receive a second signal that is indicative of an actual value of the reheater steam temperature control or manipulated variable used in the reheater section to control the steam temperature at the output of the reheater section, the controller including a routine that uses, in addition to a signal indicative of the steam temperature of the reheater section, the first signal and the second signal indicative of the reheater steam temperature control or manipulated variable to produce a control signal to be used to control: a fuel to feedwater ratio provided to the furnace/boiler combination of the steam generating boilers system, a fuel/air mixture provided to the furnace, or an amount, a quantity or a type of fuel used in or provided to the furnace, thereby controlling steam temperature of the steam generating boiler system. a boiler having a furnace, a superheater section and a reheater section coupled to the superheater section, wherein the boiler is a once-through boiler; and a controller communicatively coupled to the boiler to control operation of the boiler, the controller characterised by being communicatively connected to the reheater section to receive a first signal, other than a signal corresponding to a desired superheater spray setpoint, that is indicative of a desired value of a reheater steam temperature control or manipulated variable used in the reheater section to control steam temperature at an output of the reheater section, and to receive a second signal that is indicative of an actual value of the reheater steam temperature control or manipulated variable used in the reheater section to control the steam temperature at the output of the reheater section, the controller including a routine that uses, in addition to a signal indicative of the steam temperature of the reheater section, the first signal and the second signal indicative of the reheater steam temperature control or manipulated variable to produce a control signal to be used to control: a fuel to feedwater ratio provided to the furnace/boiler combination of the steam generating boilers system, a fuel/air mixture provided to the furnace, or an amount, a quantity or a type of fuel used in or provided to the furnace, thereby controlling steam temperature of the steam generating boiler system. a fuel to feedwater ratio provided to the furnace/boiler combination of the steam generating boilers system, a fuel/air mixture provided to the furnace, or an amount, a quantity or a type of fuel used in or provided to the furnace, thereby controlling steam temperature of the steam generating boiler system.