Towards a track maintenance planning tool

In Australian rail freight operations, track maintenance costs comprise between 25-35 percent of total train operating costs. The main aim of this paper is to describe the results of research into track maintenance planning for the medium to long-term. The paper reviews research into the tools which are currently available for the planning of maintenance activities, ranging from Expert Systems to the use of computer based optimisation techniques. The results of a survey of rail systems in Australia and overseas are also described. This survey covered the following aspects: track condition and maintenance work monitoring currently being undertaken by each rail network; the technology in use for those functions; the extent to which train operations databases are used in track maintenance planning; the maintenance activities and equipment being used routinely in rail infrastructure maintenance; the basis of how maintenance activities are being planned for; the way in which maintenance priorities are determined; the extent to which maintenance planning models are being used, together with their features and data requirements. A model to optimise long-term track maintenance is also put forward in the paper. The model can be used to quantify the impact of maintenance actions on the likely track performance. The modelling framework, and the assumptions used are detailed, together with the data requirements. The model has been designed to take into account the impacts of track condition on train operations, as well as the costs and effectiveness of maintenance activities. The paper discusses in detail the issues involved in implementing such a planning tool given the current level and availability of data in Australian rail systems. It is concluded that medium to long-term maintenance planning is currently being undertaken without taking fully into account the trade-offs between maintenance cost and net benefit to the rail business. The latter consists transit times and train arrival reliability, as well as the more direct train operating costs.