Crew and vehicle rescheduling based on a network flow model and its application to a railway train operation

For the crew rescheduling problem (CRP) and the vehicle rescheduling problem (VRP), we propose a 0-1 integer programming formulation based on a network flow model and a solution method that uses a heuristic flow modification and a local search technique. The proposed formulation is able to represent the "differences between the new and original schedules", which is a significant criterion for the CRP/VRP, though taking these differences into account is difficult for other related formulations based on the set partitioning/covering models. Implementation of a prototype system for vehicle rescheduling showed that the model is also effective for designing interactive operations between users and the computer system. The results of numerical experiments with real-world vehicle rescheduling data showed that the proposed method generated feasible solutions within a practical amount of time, and on the basis of a two-phase solution approach, the proposed method improved the evaluation values of the solution. This work could lead to practical computer systems which would effectively support train recovery operations under strict time limitations.