Proactive-Reactive Approach for Stable Rescheduling of the Train Unit Shunting Problem

Abstract

This research is focused on the proactive-reactive rescheduling process of the Train Unit Shunting Problem (TUSP) on train maintenance shunting yards. An important difference between a scheduling process and the rescheduling process is that a reschedule must be both feasible and desirable (similar to pre-schedule), while a schedule does not require desirability. Firstly, an abstract proactive-reactive rescheduling framework is proposed. This framework is proposed as a base for the general problem of proactive-reactive rescheduling. A total of four reactive rescheduling methods for the TUSP are proposed and implemented as extensions to the Simulated Annealing local search algorithm. The extensions are created in order to achieve reschedule desirability by either guiding the local search process during its iterations or influencing its starting point. Using experiments based on realistic data, it is concluded that the Simulated Annealing can be used to create reschedules that are both feasible as well as desirable. It is shown that both proposed extensions are required for the best reschedule quality. Finally, further analysis of the results shows that the schedule resilience to late arrival of trains can be improved upon by increasing the amount of time between a train arrival and the time at which its services are scheduled.