Evaluating Service Risk in Railway Capacity Utilization Using Expected Recovery Time

Different capacity-utilization levels may incur different service risks to the railway system. Previous capacity research has mainly focused on capacity measurement without evaluating the potential risks from an increase in the capacity-utilization level. This research proposes a new concept, namely, risk in capacity utilization, by using expected recovery time to quantify the service risk in capacity utilization. A corresponding computational process was also developed to assess the expected time for the railway operation to recover after potential disruptions. Results from the case study demonstrate that the service risk in capacity utilization can be obtained and compared by using the proposed concept and process. A minor increase in the capacity-utilization level in peak hours may incur a substantial risk to service reliability. In order to adjust the service plan to a desired reliability level, the locations and time intervals causing a high level of capacity risk can also be pinpointed in the risk-evaluation process. It is therefore important and beneficial to incorporate this evaluation procedure in the service-design process to ensure service reliability to customers. (C) 2017 American Society of Civil Engineers.