Scheduling tamping operations on railway tracks using mixed integer linear programming

Artikel i vetenskaplig tidskrift, 2015

A mixed integer linear programming model for the problem of scheduling tamping operations on ballasted tracks is presented and analyzed. The model improves a previously proposed one by introducing disaggregated constraints yielding in a model with stronger lower bound from the continuous relaxation of the binary variables. A more general cost structure is proposed; a structure having the possibility of including setup costs for the tamping operations. The problem considered is shown to be NP-hard. A numerical study is performed to evaluate the performance of the model compared to two simple policies for constructing maintenance schedules. The computational results show that the maintenance costs can be reduced by up to 10% as compared with the best policy investigated.