Efficient maintenance strategy through System Dynamics

Abstract

In times when economic efficiency of traffic systems is getting more and more important, it is necessary to have an efficient maintenance strategy, because maintenance costs have been identified as significant cost drivers. This holds true especially for railway signalling in which the long life cycle of elements has a high impact on the costs. In addition, a maintenance strategy is required to fulfil the high standards for availability and safety in the railway sector. While different strategies are available (e.g. corrective or preventive, predetermined or condition based, etc.), each strategy has various options of processed period, duration, costs, impact on the maintained item, etc. This makes it a difficult task to find an efficient maintenance strategy for a system or even a network. The Institute of Transportation Systems has therefore analysed cause-and-effect chains between system condition, availability, maintenance activities, and costs. The identified cause-and-effect chains are modelled with the use of System Dynamics. System Dynamics is a method which has established to analyse and model complex dynamic systems. The developed models do not only enable the user to compare the efficiency of different maintenance activities with each other, but also provide the possibility to determine a combination of these activities leading to an overall system maintenance strategy at a cost minimum through optimisation. This allows infrastructure managers to evaluate their current maintenance program and to determine an economically improved strategy for the future.