An evolutionary and constructive approach to a crew scheduling problem in underground passenger transport
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Operations management of subway systems is associated with combinatorial optimization problems (i.e. crew and train scheduling and rostering) which belong to the np-hard class of problems. Therefore, they are generally solved heuristically in real situations. This paper considers the problem of duty generation, i.e. identifying an optimal trips set that the conductors should complete in one workday. With regard to operational and labor conditions, the problem is to use the lowest possible number of conductors and minimize total idle time between trips. The problem is modeled and solved using a constructive hybrid approach, which has the advantage of visualizing a solution construction similar to the manual approach typically used. Our approach takes advantage of the benefits offered by evolutionary methods, which store a candidate solutions population in each stage, thus controlling the combinatorial explosion of possible solutions. The results thus obtained for problems similar to those that are solved manually in the Santiago Metro System were compared with two alternative approaches, based on tabu search and a greedy method. The hybrid method produced solutions with the minimum number of duties in six of the ten problems solved. However, the tabu search method provided better results in terms of idle time than either the hybrid method or the greedy method.
KeywordsGraph search methods Evolutionary algorithm Crew scheduling
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- Bengtsson, L.R., Galia, T., Gustafson, C., Hjorring, C., Kohl, N.: Railway crew pairing optimization. C. R. a. T. Report, Carmen Systems AB (2004) Google Scholar
- Caprara, A., Monaci, M., Toth, M.: A global method for crew planning in railway applications. In: Daduna, J., Voss, S. (eds.) Computer-Aided Transit Scheduling. Lecture Notes in Economics and Mathematical Systems, vol. 505, pp. 17–36. Springer, New York (2001) Google Scholar
- Freling, R., Wagelmans, A.P.M., Paixao, J.M.P.: An overview of models and techniques for integrating vehicle and crew scheduling. Comput.-Aided Transit Sched., Proc. 471, 441–460 (1999) Google Scholar
- Friberg, C., Haase, K.: An exact branch and cut algorithm for the vehicle and crew scheduling problem. Comput.-Aided Transit Sched., Proc. 471, 63–80 (1999) Google Scholar
- Gaffi, A., Nonato, M.: An integrated approach to ex-urban crew and vehicle scheduling. Comput.-Aided Transit Sched., Proc. 471, 103–128 (1999) Google Scholar
- Morgado, E.M., Martins, J.P.: CREWS_NS—Scheduling train crews in the Netherlands. AI Mag. 19(1), 25–38 (1998) Google Scholar
- Pearl, J.: Intelligent Search Strategies for Computer Problem Solving. Addison-Wesley, Reading (1984) Google Scholar
- Russell, S.J., Norvig, P.: Artificial Intelligence: A Modern Approach. Prentice-Hall, Englewood Cliffs (2002) Google Scholar