Optimum Maintenance Scheduling For Locomotives Through Preventive Maintenance Strategy

With the rapid development of railway construction, locomotives are the most important components for transportation and their quantities have achieved constant growth. The quantity of national railway locomotives is about 21,100 at the end of 2014, increasing by 261 over the previous year. Among them, electric locomotives account for 55% and diesel ones account for 45%. Facing the huge quantity of railway locomotives, making a reasonable maintenance scheduling and reducing operation cost for locomotives have become an urgent requirement to the railway operation department. This thesis carries out a research on such need based on maintenance theories. The main content of this thesis includes as below.(1) This thesis investigates the method of confirming the initial state and key components of locomotives. Then, according to delay time theory and taking reliability and availability as its restrictive condition, a single component preventive inspection model is proposed and then it gives a computational analysis of examples.(2) This thesis considers a single component’s preventive maintenance cycle as the sum of the best inspection interval and delay time. After getting the best inspection interval, this thesis takes reliability as its restrictive condition, imports maintenance improvement factor which is modified due to the initial state of locomotives and figures out the delay time of a single component. Thus the best preventive maintenance cycle of a single component is calculated. From this work, taking reliability as the opportunistic and group maintenance threshold value, opportunistic and group preventive maintenance scheduling optimization models are proposed through aiming at the minimum maintenance costs and the maximum availability respectively. Finally, a genetic algorithm is employed to make a computational analysis of examples.(3) This thesis applies the proposed models to SS4B-type electric locomotives in a railway line. The best preventive maintenance scheduling is solved by analyzing the data of investigation. The result shows that the proposed models can improve the efficiency of preventive maintenance scheduling for locomotives and provide a reliable evidence for operation department.(4) By combining maintenance scheduling with operation plans for locomotives, this thesis analyzes the impact of optimal maintenance scheduling on the working performance and turnaround indicators of locomotives. The result shows that the optimal maintenance scheduling for locomotives can shorten their turnaround time, decrease their repair rate and requirement coefficient and improve their operation efficiency. Moreover, it can offer a help tool for the locomotive working diagram in methodologies.