Given the complex interaction between the many factors which contribute to track degradation, it is critical to have a logical analysis process to ensure that the money spent on unplanned and unscheduled track maintenance is not well in excess of budget expectations. The "Top Down" approach looks first at the rail and then in turn at the sleepers and fastenings, down through the ballast, capping layer and subgrade and, finally, drainage systems to see where the problem is occurring. Sampling and testing may then be needed to further define problems not wholly apparent visually. The "Top Down" diagnostic analysis provides a common sense holistic approach to track investigations and standardises the identification of track and substructure faults. When track faults have been correctly identified, the most appropriate and cost effective remedial options can then be applied.