An optimization model for scheduling freight trains on a single-rail track

In many countries, a rail network consists of a series of single lines with sidings where intertrain interactions (meeting, passing) occur. An effort has been made in this paper to study two of thesenetworkrelated issues: 1) scheduling freight trains in a singleline corridor while ensuring the interactions to happen safely and 2) allocating freight to the scheduled trains considering the freight due/release date and train’s weight/capacity. To better illustrate the realworld freighttrains’ scheduling problems, both the scheduling and allocation problems have been addressed. Minimizing the trains’ traveling time, allocating maximum freight to the scheduled ones, and minimizing the total freight tardiness at the related destination are the objective functions ofthis study. Both problems and their solutions have been addressed separately using integer linear programming models, but an integrated novel heuristic algorithm has been proposed to solve them. The computational results demonstrated through a generated data set show both the modelvalidation and the efficiency of the heuristic algorithm. This heuristic algorithm has been so designed to incorporate the practical operational railway rules with modest modification and although its outputs slightly differ from the exact solutions, it can solve both models simultaneouslyin large scale problems.