Whole Life Cost Modelling For Railway Drainage Systems Including Uncertainty

The UK railway drainage system is facing significant asset management challenges due to the presence of large numbers of assets with long asset life cycles. Maintaining the required asset performance economically and efficiently, while complying with the relevant legislation and regulations is a major concern for Network Rail's asset managers. The whole life cost (WLC) approach has been developed and implemented in many industries and has proven its usefulness in the management of assets, particularly for assets with long life spans and in situations of uncertain future expenditure. WLC involves estimating the present value of the total cost of ownership over any asset's likely operational life. It is often integrated with decision support tools to enable a more robust decision making process. This has significant benefits in regulated industries in which all expenditure requires clear justification. This project developed a whole life cost model suitable for railway drainage systems, considering the uniqueness and complexity of costs associated with railway business operations. This WLC model can offer prediction of the transitions of drainage assets condition grades; assessments of drainage system operational performance; and provide realistic estimates of financial requirements in order to achieve desired operational performance; and evaluate the financial consequences due to loss of performance. This WLC model provides the information to build decision support tools that can help Network Rail prioritise drainage maintenance and refurbishment based on available and anticipated budgets and operational risks. This work demonstrated that the whole life cost modelling approach can provide an ideal solution for sustainably maintaining drainage systems while optimising the total cost of ownership and minimising operational, social and environmental impacts. The developed WLC approach enables asset managers to make decisions both on a strategic and operational level. Strategically, WLC approaches can forecast the overall budget and workload needed to maintain an infrastructure system over its assets' lifetime or a predefined financial period. Tactically, it can provide the asset owner with an optimum renewal, maintenance and utilisation plan under a given risk/cost requirement. This project provides WLC approaches that operate at both a strategic and tactical level for the UK railway drainage system. The methods developed in this thesis are now being implemented by NR into operational practice.