A model to obtain optimal designs of railway overhead knuckle junctions using simulation

The design of overhead knuckle junctions in railway electrification is a crucial and complex problem. Non-optimal overhead knuckle junction designs cause limitations in train speed and, most important, malfunctions and breakages. Most railway companies have regulations for the design of overhead knuckle junctions. Those regulations have been defined by the experience, but, as far as we know, there are no computerized software tools to help with the task of designing and testing optimal solutions for overhead knuckle junctions. In this paper we present a simulator that allows to look for optimal configurations of overhead knuckle junctions. The simulator starts from a model based on the description of the problem that includes all the significant elements that may affect the design process, in order to find an optimal solution in terms of reliability and safety. The obtained design will be the more reliable to face failures, such as excessive wire and pantograph wears, wrong geometry configurations of the catenary, or electricity supply notches. The simulator also allows to evaluate current designs, so as to prove their possible flaws. This paper describes the simulation algorithm developed, the input data needed to define the experiments, and the achieved results. As the simulator requires heavy computational resources, high productivity parallel issues have been included in the implementation to exploit current multi-core processors. The validation and performance evaluations were made in the paper through the simulation of overhead knuckle junction designs over real switches. Their analysis will show the feasibility and applicability of our simulator.