Design Optimization of Switch Rails in Railway Turnouts

Paper i proceeding, 2012

Inspired by the manufacturing process of switch rails for railway turnouts, a method for the optimization of switch rail profile geometry is presented. The switch rail profile geometry is parameterized with four design variables to define a B-spline curve for the milling tool profile, and two design variables to prescribe the deviation from the nominal vertical path of the milling tool. The optimization problem is formulated as a multi-objective minimization problem with objective functions based on the contact pressure and the energy dissipation in the wheel–rail contact. The front of Pareto optimal solutions is determined by applying a genetic type optimization algorithm. The switch rail profile designs are evaluated by simulations of dynamic train–turnout interaction using a commercial code for multi-body dynamics. The vehicle model is a freight wagon with Y25 bogies and 25 metric tonnes axle load. Traffic is simulated in both travelling directions in the diverging route of a 60E1-760-1:15 turnout. It is concluded that the obtained set of Pareto optimal solutions corresponds to a rather small variation in design variables where increased profile height and increased profile shoulder protuberance are preferred for both objectives.