Exploring different alert limit strategies in the maintenance of railway track geometry

This paper explores a quantitative model with different maintenance strategies to control railway track geometry degradation in Portugal. The alert limits put forward by the international standards are assessed regarding the planned and unplanned impacts associated with those limits, namely preventive maintenance and renewal costs, corrective maintenance costs, planned infrastructure delays due to changes in the maximum permissible speed, and unplanned infrastructure delays due to temporary speed restrictions. The effects of different choices for the alert limits of the main quality indicators for railway track geometry are assessed, considering a cost penalty due to delays set by the regulatory entity. Finally, a sensitivity analysis is conducted on the effect of this delay cost penalty on the optimized choice of the alert limits for both quality indicators.