Designing granular layers for railway tracks using ray optimization algorithm

In this paper, the recently developed meta-heuristic algorithm, named rayoptimization (ro), was applied to optimize the thickness of granular layers in railwaytracks. ro is a multi-agent algorithm, each agent of which is modeled as a ray of lightthat moves in the search space in order to nd global or near-global optimum solutions. toutilize ro, considering structural and serviceability constraints, rst, hypothetical valuesof three thicknesses were assigned to the layers. then, stresses under the sleeper and on thesubgrade layer were compared with the allowable values. the total minimum thickness ofthe layers was also compared with possible minimum thickness (serviceability constraint)and then minimum thickness values were selected. optimization results showed that themoment of inertia of the rail had no signicant impact on the minimum total thicknessof the ballast and sub-ballast layers. on the other hand, train speed and axle load werethe parameters that had a considerable eect on the minimum total thickness of granularlayers in the railway track.