A method and system for assessing the condition of a pipeline in a pipeline system is disclosed. The method includes generating a pressure wave in the fluid being carried along the pipeline system at a generation location along the pipeline system, detecting a first pressure wave interaction signal at a first measurement location along the pipeline system resulting from an interaction of the pressure wave with localised variations in the pipeline and then detecting synchronously a second pressure wave interaction signal at a second measurement location along the pipeline system resulting from the interaction of the pressure wave with localised variations in the pipeline. The method then involves comparing the first and second pressure wave interaction signals to determine a location of individual features in the first and second pressure wave interaction signals with respect to the generation location, the individual features corresponding to pressure wave reflections from localised variations in the pipeline and characterising the individual features to assess the condition of the pipeline.