This paper proposes a methodology for the analysis of operational risks that are caused by railway infrastructure failure. The objective of this methodology is to assist the engineers that manage railway infrastructure maintenance to forecast the frequency of these operational risks, the cost of rehabilitating railway infrastructure after these operational risk events and the impact of railway infrastructure maintenance strategies on the frequency and cost of these operational risk events. The proposed operational risk methodology is applied in a case study concerning a railway company called African Railway Ltd for the sake of confidentiality. The train derailments that are caused by infrastructure component failure are analysed in the case study. Historical data and the results of questionnaires that were used during face-to-face interviews are discussed. The frequency of train derailments, the cost of rehabilitating railway infrastructure after train derailments and the impact of railway infrastructure maintenance on these two issues are forecasted. The case study concludes with a comparison of the forecasted and actual frequency of train derailments and cost of rehabilitating the railway infrastructure after a train derailment.