A set of dynamic filtering and prediction equations for use on a large scale gas pipe-line network are obtained on the basis of a simplified model. An algorithmic approach enables the filter to be structured and initialised automatically to particular applications on the input of commonly available network parameters. The proposed algorithm has relatively modest computational requirements. The response of the simplified dynamic network equations to a standard demand flow profile compares favourably with that previously obtained using a more complicated model. Simulation results illustrating filter performance to be satisfactory are also given.