•SPAD costs in Australasia are minimally documented and opaquely presented.•Little is known about estimated distribution of preventative and reactive SPAD costs.•A multi-case study was undertaken of costs incurred by 8 rail operators across Australasia.•The ratio of preventative to reactive costs in low-risk SPAD mitigation was widely varied.•Differences in organisational culture and financial obligations may shape mitigatory spending. This study sought direct estimates of incidence, preventative costs, and reactive costs associated with the occurrence of low risk (‘typical’) Signal Passed at Danger (SPAD) events in Australasian rail. In a cross-sectional multiple-case design, a descriptive questionnaire was sent to eight operators, and completed by managerial personnel with responsibility for SPAD-risk mitigation. Items addressed SPAD frequency, operator delays, and a range of preventative and reactive costs associated with low-severity (‘low-risk’) SPADs. Delay costs varied between cases, with each having different organisational size and network density. Preventative costs were mostly comprised of internal SPAD prevention team maintenance, participation in a collaborative SPAD Group, and resultant network modifications. Reactive costs were largely comprised of driver-related factors and in two cases, of higher low-risk investigation and regulatory costs. The ratio of preventative to reactive costs (P:R) varied widely, approaching equilibrium for two cases only—both participated in internal and external SPAD preventative team consultation. One freight organisation noted a large P:R imbalance due to very low preventative costs. Low-risk SPADs represent a host of substantial annual costs for each Australasian passenger- and freight-rail organisation. As this study gives preliminary estimates, these likely underestimate the full costs, as multiple other factors are yet to be accounted for. This study justifies the need for detailed analysis of SPAD-associated costs to contrast data from multiple rail organisations, and a clearer picture of how organisational expenses are allocated within SPAD prevention and reaction.