The double stack railcar allocation problem at marine container terminals

This paper introduces and solves a real-world problem that arises at container ports, namely the double stack railcar allocation problem. The key challenge in the double stack railcar allocation problem is to balance the number of containers loaded and the railcar usage, while respecting the loading constraints for double stack trains. To capture the key characteristics of the double stack railcar allocation problem, an integer linear optimization model is presented. The model is found to be computationally prohibitive for a state-of-the-art off-the-shelf solver (CPLEX). Hence, a tailored solution method is proposed that manages to drastically reduce the computation times, sometimes by more than 99%. In a detailed case study, insights into the double stack railcar allocation problem are revealed and discussed.