Optimal Design of Tractive Layout for Minimizing the Insufficient Displacement of Railway Turnout

Railway turnout is the key infrastructure for trains to change their routes. In order to ensure the smoothness and safety of the train’s passing through turnouts, the insufficient displacement (ID) of switch rails after their conversions must be controlled within a permitted range. During design stage, it is quite important for the reduction of the ID to reasonably arrange the tractive points. In the existing literature, a feasible tractive layout is commonly suggested through the manual analysis using the finite element model of the switch rail. However, as the design space may explode for long rails with multiple tractive points, it is time-consuming for such labor-intensive methods to search a feasible tractive layout, and the result may be non-optimal. Therefore, it is necessary to develop an efficient method to arrange the tractive points optimally in order to minimize the ID. To this end, we propose a physics-informed optimization method for the design of the tractive layout. First, a tailored direct stiffness method is introduced to accurately estimate the ID given any tractive layout and frictions. On this basis, we establish an optimization model for the selection of the tractive locations with the objective of minimizing the expectation of the ID. To address the sparsity issue of the decision variable, an Encoding Rule with a hierarchical indexing method is proposed to improve the efficiency of genetic algorithm. Next, the number of tractive points is determined. Finally, several sets of experiments are conducted to demonstrate the effectiveness of the proposed method, which decreases the ID by 25.61% and 12.7% in terms of the maximal and mean values for the case with the switch of length 44.1m.