The problem of assigning locomotives to train-segments is very important for railway companies, in view of the high cost of operating locomotives. The problem considered in this paper is to provide sufficient power to pull trains on fixed schedules, using heterogeneous consists. A list of preferred locomotives exists for each train-segment. The power required to pull a train-segment is determined according to the train's weight and length, as well as the route segment on which it must travel. Finally, locomotives requiring inspection must be sent to appropriate shops within a given time limit.