Branch-and-price for a European variant of the railroad blocking problem

In wagonload traffic, a production form in railway freight traffic, small groups of wagons have to be transported. In order to decrease transportation costs, wagons from different relations are consolidated. In railyards trains can be separated and rearranged to new trains. The costs arising from this process, which is called reclassification, must be balanced with the transportation costs. The minimization of total costs can be formulated as a network optimization model. We introduce a branch-and-price approach for the considered problem. Moreover, we present specialized cuts, which can be incorporated into the branching scheme. Solutions obtained from our implementation can keep up with results computed by CPLEX.