Optimal Freight Train Classification using Column Generation

Authors Markus Bohlin, Florian Dahms, Holger Flier, Sara Gestrelius

Thumbnail PDF


  • Filesize: 0.69 MB
  • 13 pages

Document Identifiers

Author Details

Markus Bohlin
Florian Dahms
Holger Flier
Sara Gestrelius

Cite AsGet BibTex

Markus Bohlin, Florian Dahms, Holger Flier, and Sara Gestrelius. Optimal Freight Train Classification using Column Generation. In 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems. Open Access Series in Informatics (OASIcs), Volume 25, pp. 10-22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)


We consider planning of freight train classification at hump yards using integer programming. The problem involves the formation of departing freight trains from arriving trains subject to scheduling and capacity constraints. To increase yard capacity, we allow the temporary storage of early freight cars on specific mixed-usage tracks. The problem has previously been modeled using a direct integer programming model, but this approach did not yield lower bounds of sufficient quality to prove optimality. In this paper, we formulate a new extended integer programming model and design a column generation approach based on branch-and-price to solve problem instances of industrial size. We evaluate the method on historical data from the Hallsberg hump yard in Sweden, and compare the results with previous approaches. The new method managed to find optimal solutions in all of the 192 problem instances tried. Furthermore, no instance took more than 13 minutes to solve to optimality using fairly standard computer hardware.
  • Column generation
  • integer programming
  • scheduling
  • shunting
  • classification
  • marshalling
  • transportation
  • railways


  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    PDF Downloads
Questions / Remarks / Feedback

Feedback for Dagstuhl Publishing

Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail