Scheduling of Waterways Maintenance Interventions applying Queueing Theory

The navigability of German waterways depends on the functioning of its infrastructures, such as locks and weirs. Since most of them have almost reached the design working life, they should undergo maintenance and eventually repair. However, these actions imply to put the structure out of service for a certain period. For this reason, inoperative periods should be planned in such a way that the operability of the network is maximized. In this paper, an application of queueing theory to the scheduling of maintenance interventions on waterways infrastructures is proposed. The performance of one single lock undergoing inoperative periods namely the average queue size is assessed through an approximated but simple formula. This approach allows comparing different maintenance policies, and eventually the choice of the optimal one. Results confirm that a maintenance strategy based on short and frequent interruptions has less impact on the operability of the network compared to those based on longer and sporadic intervention.