The conflict resolution at connected railway junctions

Traffic conflicts at railway junctions occur when trains arrive at the junctions at the same time. Conflicts result in train delays, leading to a loss of punctuality, thus hampering the quality of service. A sensible right-of-way assignment will reduce the total weighted delay of all trains, but the number of possible assignments is vast, especially at connected railway junctions. Genetic algorithm provides a quick means to locate a near-optimal assignment within a limited time, but crossover (a genetic operator) often produces right-of-way assignments that violate the constraints imposed by the definitions of the chromosomes. This paper proposes two scanning methods to locate the violations and modify them before they are admitted to the next generation. Simulations are carried out to study the performances of the scanning methods.