A Mathematical Model and a Hybrid Algorithm for Robust Periodic Single-Track Train-Scheduling Problem

A robust periodic train-scheduling problem under perturbation is discussed in this paper. the intention is to develop a robustness index and to propose a mathematical model which is robust against perturbations. some practical assumptions as well as the acceleration and deceleration times along with periodic scheduling in addition to a practical new robustness index are considered. the aim is to obtain timetables with minimum traveling time that are robust against minor perturbations,while the unnecessary stops are minimized. in general,the spread of delays in the railway system is called delay propagation. we show that in addition to this phenomenon,there exists a more complicated case in periodic type of scheduling that is the fact of delay propagation from one period to the next. in fact,if the delays of a period are not absorbed by the next one,the size of delays may converge to infinity. we name this as delay intensification. furthermore,we develop a hybrid heuristic algorithm which is able to find near-optimal schedules in a limited amount of time and can absorb perturbations. to validate the algorithm,a new lower bound is introduced. © 2016,iran university of science and technology.