Preventing broken-rail caused derailments is a high priority for the rail industry. The currentrnpractice is to periodically inspect rails using non-destructive technologies. Determining therneffective inspection frequency is a critical decision in railway infrastructure management.rnThis thesis discusses some applications of the modelling work to rail defect management. Inrnparticular, main applications are the determination of remedial actions and effective inspectionrninterval on the basis of the quantitative approach as well as the adaptation of rail inspection andrnmaintenance procedure.rnThe frequency of rail inspection tends to vary from one railroad to another, yet it is usually basedrnon either time or traffic tonnage. Railroad companies have evolved their rail inspection schedulesrnempirically based on long field experience. Rail defect management refers to the development andrnimplementation of strategies to control the risk of rail failure. The primary method to control thernrisk is a rail inspection through nondestructive evaluation and is a replacement of rails based onrnthe remedial action plan.rnTo demonstrate the feasibility of the above applications first, a Linear Elastic Fracture Mechanicsrn(LEFM) analysis which can predict a crack size in a rail head, web and base is performed. Second,rnFirst Order Reliability Method (FORM) of analysis evaluates the reliability of a rail, consideringrnsome uncertainties of parameters. Third, an Event Tree (ET) analysis represents systematically allrnpossible events and actions regarding rail defect management. Finally, a Life- cycle cost (LCC)rnestimation formulates the total expected cost during the service life are conducted.rnBased on the analysis results, the mechanism for remedial action is developed based on criticalrncrack size at rail head, web and base as well as rail reliability value to help infrastructure managerâ€™srndecision. Then, effective number of rail inspection frequency is determined as three times a yearrnto prevent the occurrence of rail failure by taking the required action at the right time, and extendrnthe rail life expectancy, reduce the rail maintenance work and its cost. Finally, appropriate railrninspection and maintenance strategy model (flowchart) is adopted for Ethiopian railway industry.