Modelling the cost of railway asset renewal projects using pairwise comparisons

This research article presents the development process of a cost-estimating model for railway renewal projects at the early stage of a project life cycle. The model comprises four main stages: creating a project structure that composes the goal, project criteria, and alternatives; collecting the necessary data in the form of pairwise comparisons made by a domain expert; producing alternative weights using a geometric mean; finally, employing an algorithmic method using the produced alternative weights and the known cost of one alternative per criteria. The practical implications of the developed model are its ability to estimate renewal project costs of railway assets when there is a lack of quantitative data and detailed project definition. The process provides a transparent and a structured way of formalizing subjective judgments, which produces a three-point estimate as the resulting output. The model is described and validated using a switch and crossing case study.