Optimal rail profile design for a curved segment of a heavy haul railway using a response surface approach

To determine the optimal design of the rail profile for a curved segment of a heavy haul railway, an optimization method that considers the extent of rail wear over the entire design cycle was developed. The approach is based on wheel–rail rolling contact theory, vehicle–track dynamic theory and nonlinear programming theory. The changes in the rail profile were analyzed using an updating strategy that considers random irregularities in the railway track. The minimum average metal loss from the vehicle in terms of wear and grinding for the whole design cycle was regarded as the design objective, and discrete point coordinates on the rail were regarded as the design variables. A radial basis function was used to establish an approximate model, which formed an explicit function between design variables and design objectives. The optimization model was established on this basis, and a genetic algorithm was used to solve the optimization model for the optimized profile. The maximum passing gross load for the whole design cycle reached 150.74 x10⁶ t, an increase of 139.73% compared with the standard profile, which achieved the purpose of prolonging the service life of the rail.