Simplify Twin Crane Scheduling in Railway Yard by Spatial Task Assignment

This paper studies the simplification of twin crane scheduling problems in a railway yard. Compared with single crane scheduling problems, twin crane scheduling problems additionally involve the task assignment and cranes' no-passing constrains, which hinder the direct extension of the single crane scheduling algorithms, making it almost intractable for most large-scale real-world problem instances. In order to make single crane scheduling algorithms applicable, a spatial task assignment method is proposed to decouple the problem for each crane, which is further solved by an approximate TSP solver, and an event-based rolling horizon method is implemented to approximately solve the decoupled problem efficiently in multi-period scheduling. Simulation results show that the proposed spatial task assignment method and event-based rolling horizon method can solve twin crane scheduling problems effectively.