Author(s)

T. G. Tendayi, C. J. Fourie

Abstract

Having a life cycle framework in place to support the reliability, availability maintainability and safety of all mission critical assets has become an integral part of decision-making in the railway environment. In this paper, one such framework is investigated and developed for use in a railway rolling stock environment with emphasis on the cost of ownership and effective maintenance and replacement strategies that influence it. The framework consists of taking typical mission critical components, in this case a traction motor, together with their failure and maintenance history. All costs related to the operation and maintenance of these traction motors throughout their life-cycle were determined. The next step involved considering different scenarios under which the component can be used in terms of operations, maintenance and replacement considerations. In this study, the three scenarios are: 1. Keep running the component as-is with the current maintenance strategy; 2. Replace the component with a completely new one and develop a maintenance strategy to support it; 3. Operate with a standby or redundant component. The decision on which scenario to take is then based on the one with the most favourable net present value after performing life cycle costing over a specified period of time. A typical railway rolling stock maintenance organisation in South Africa is used to highlight the practical implications of such a framework and how the company can make informed decisions on the appropriate decisions to take. The overall conclusion of this study is that such a framework is useful and that it can be used as a basis for estimating LCC across a spectrum of critical assets found in the rolling stock environment.

Keywords

life cycle costing, maintenance strategies, railway rolling stock