Overview of Optimization Models and Algorithms for Train Platforming Problem

In this paper, an overview of recent advances in the research on train platforming problem (TPP) is presented. The TPP is usually the last problem encountered in planning a railway system which occurs after a schedule of trains in a railway network (train timetable) has been determined. It aims to map a given train timetable to an existing station infrastructure. This process is critical as it determines the feasibility of an optimally generated train timetable along a railway line at station(s) to be visited by trains on the timetable. This optimization problem is in most stations solved manually, and it is a time consuming and error-prone process. Several computer programs are now being developed to aid infrastructure managers and train operators as decision support systems in solving this problem. This paper presents some of these solutions. However, due to variations in operating policies of railway industries in different countries, several variants of this problem exist in the literature. These variations could be seen in the solution approach through the importance attached to level of service, safety of operations, capacity utilization, etc. These variations and the various optimization techniques adopted by researchers are also discussed in this paper. Currently, most models and algorithms presented in literature are not ready for use as commercial systems. Integrating such systems into real-life planning and operations is crucial for efficient use of railway systems.