Optimized Allocation of Locomotives to Trains, in the I.R.I Railway System

Rail lines consist of a big fleet of different kinds of locomotives. Allocating the locomotives to the trains is one of the operational purposes in railways. Considering the network development and some out of service locomotives, the improved operation of locomotives is of special importance. Regarding the traditional allocation, there is no appropriate utilization of the locomotives presently, which is one of the reasons for the inappropriate allocation of locomotives to the trains. In recent studies, the items like different traction powers of each locomotive, the possibility for combination of different kinds of locos and utilization of passenger and freight locomotives have not been considered. Therefore in this research, a new mathematical model for locomotives allocation to trains has been presented, which is more compatible with RAI’s structure. The presented model is solved using GAMS software by solver Cplex 7.0 and shows that by improved allocation of the locomotives to the trains, in the existing conditions, nearly %20 can be saved by operation of locomotives.