Usefulness of quantifying effects on rail service when comparing intervention strategies

Abstract

Railways are critical infrastructure systems because their construction, use, operation, maintenance and development affect multiple stakeholders within society. To ensure that these systems function as intended over time, railway managers execute interventions. Railway managers are interested in determining which interventions to execute by considering the trade-offs between the intervention costs and effects on service consistently and transparently. Currently, however, this is not possible, because existing methodologies use qualitative indicators instead of quantifying the rail service directly. This paper shows how the direct quantification of the effects on rail service per unit time enables interventions to be selected by making optimal trade-offs between intervention costs and effects on service when the acceptable service levels are respected. The usefulness of direct quantification is demonstrated by comparing two sets of intervention strategies for the track, switches and bridges of an example network for 30 years, by using direct estimates of service and four service indicators, state, reliability, availability and safety. As railway management moves from qualitative to quantitative and data-driven decision-making, the direct quantification of the effects on service provides a more informative way to compare intervention strategies than the use of service indicators.