1. A method of controlling a gas distribution system having at least one pipeline section and at least one air separation plant controlled by a supervisory control system responsive to production requests to direct a production rate of at least one gaseous product to be consumed by at least one customer connected to the at least one pipeline section, said method comprising: continually measuring pressure within the least one pipeline section; the pressure being dependent upon an actual flow rate of the at least one gaseous product within the at least one pipeline section; and controlling the pressure to be within a range that will ensure that the at least one customer will be able to obtain a required flow rate of the at least one gaseous product from the at least one pipeline section by continually: storing pressure values of the pressure and production request values of production requests associated with each of the pressure values in a rolling history; inputting said pressure values and production request values as controlled variables and manipulated variables, respectively, into a model predictive controller; calculating, within the model predictive controller, over a prediction horizon, an open loop response of the pressure within the at least one pipeline section and a set of production request changes of the at least one air separation plant required to at least in part restore the pressure to a target value within said pressure range from said open loop response; the calculation of the target value, the open loop response, and the set of production request changes being based on at least one empirically determined step response model of pressure within the at least one pipeline section in response to a unit production change in the request value of the at least one air separation plant and the set of future of production request changes being optimized to simultaneously minimize deviations of each of the future changes and the pressure from the target value over the prediction horizon; and inputting a first of said set of production request changes into said supervisory control system.