Execution time estimation of recovery actions for a disrupted railway track inspection schedule

Track geometry quality is periodically updated upon arrival of new track measurements to maintain target levels of track reliability, availability, safety and ride comfort. The information chain for n consecutive track segments could be temporarily discontinued beyond the nearest inspection time in the occurrence of disruptions. This situation demands immediate but feasible recovery action(s) to avoid losing the reserved track possession(s) while maintaining railway line operational safety. Not only would a penalty of cancellation possession be imposed, but the disrupted schedule may also trigger other consequences such as cascading track component failure and train delay. While reputation at the organization level has better value today, maintenance departments should avoid overdrafts to pay recovery costs but use profit gained from affected track segments. In line with this goal, this study develops an optimization model based on track profitable capacity and reliability to estimate the time when a recovery action should be ideally executed. Operational reliability of n track segments subject to a sudden change/shift in track condition degradation path is evaluated according to consecutive k-out-of-n: a Failure system model. Simulation results highlight that as disruption time approaches the nearest inspection time, the execution time of recovery action decreases where the corresponding proportionality constant is determined from the track capacity per unit time. Based on the results, the proposed model would be a valuable decision-support tool for managing a disrupted track inspec-tion schedule.