چكيده به لاتين
Today, a large volume of railway track maintenance projects are defined and planned each year. Also, due to the very low manpower efficiency and speed of machinery, the use of these machines is an inseparable part of major projects of maintenance and repair of the railway track. Therefore, based on shortage and limitation of track maintenance machines, in order to increase the productivity of these machines and number and volume of projects that can be carried out by these machines, we require accurate and applicable scheduling.
The problem we face is track maintenance machines scheduling problem (TMMSP). This problem involves assigning and scheduling activities in various track maintenance and repair projects. Projects, activities, as well as machines, have different types. Each project, depending on its type, includes activities of different types. Each machine can also perform certain types of activities based on its type.
The fact is that the approach for the optimal and applicable track maintenance machines planning was considered. In accordance with the constraints and conditions of the real world, the required mathematical model was designed and implemented. The objective function of this mathematical model includes minimizing the total cost of maintenance machines travel and the constraints violations. The constraints violations includes the cost of non-performing activities, the cost of incomplete projects, the cost of using machine with lower priority and the cost of unemployed parts of multifunction machines. In the constraints section, real world constraints were imported into the mathematical model. Some of these constraints include performing the activities, reducing the number of incomplete projects, concurrency of activities in one project, and constraints on the carrying out activities by multifunction machines.
After preparing the optimization model, the planning of track maintenance machines in the actual condition of the Iran railways has been implemented. Eventually the results were compared with Iran railways manually prepared plan. The result of the comparison showed that using this optimization model increases the number of planned projects and activities of maintenance machines. It was also found that the use of the proposed model would increase the kilometer-machine and could increase the productivity of machines per 100% occupied machines.
