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dc.contributor.authorWlodarczyk, Romainen_US
dc.date.accessioned2014-03-14T20:31:46Z
dc.date.available2014-03-14T20:31:46Z
dc.date.issued2009-07-20en_US
dc.identifier.otheretd-02142009-051637en_US
dc.identifier.urihttp://hdl.handle.net/10919/31235
dc.description.abstractThe empty railcars repositioning strategy generates no income but is crucial for a good service quality, it should then satisfy two main objectives: fullling the customer demand and generating as little expense as possible. Moreover, because of breakdown or heavy traffic, variation on travel times happens to be the main cause of uncertainty in railroad scheduling and must be taken into account to suggest a robust planning.

This thesis presents the linear program used in a prototype tool for the optimization of empty railcar repositioning strategy designed for the SNCF1. The resulting schedule is computed with CPLEX and minimizes moving cost, delay and unfulllment penalties. Substitutions of railcar categories are also permitted and eventually penalized. In addition, uncertainty on travel times is handled by considering the expected cost of a move (regarding delay probability and possible penalties) and by adding slack periods at the end of moves. The robustness can be modulated through the use of a cursor. Finally, the model enforces a decision making process previously dened by the SNCF to ensure that the suggested planning can be easily grasped and trusted by users.

Schedules have then been generated based on randomly generated data and simulated. Results show a potential saves of 10% on considered costs and a good range of use of the robustness cursor is suggested.

Finally, paths for improvement of this prototype are proposed to meet the eventual schedulers' further needs in order to move forward the production of this tool at the company scale.

en_US
dc.publisherVirginia Techen_US
dc.relation.haspartmasterthesis.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectOptimizationen_US
dc.subjectFreighten_US
dc.subjectRailen_US
dc.subjectRepositioningen_US
dc.subjectEmpty Railcarsen_US
dc.titleEmpty Railcar Repositioning Subject to Travel Time Uncertaintyen_US
dc.typeThesisen_US
dc.contributor.departmentIndustrial and Systems Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineIndustrial and Systems Engineeringen_US
dc.contributor.committeememberHanif D. Sheralien_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-02142009-051637/en_US
dc.contributor.committeecochairJoel A. Nachlasen_US
dc.contributor.committeecochairPierre Lemaireen_US
dc.date.sdate2009-02-14en_US
dc.date.rdate2013-05-20
dc.date.adate2009-08-10en_US


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