Tuley Y. Rationalization of the arrangement, maintenance norms for a rail track in small radius curves to increase the rail operational life

The thesis deals with scientific rationale and practical solution to the problem of higher operational life of rails laid in curves of a radius of 450m and less by rationalizing the track arrangement, maintenance and operation norms. On the base of the data on the number of technical failures of the track due to side wear, it was concluded that the reasons were in the special nature of the vehicle/track interaction in curves. The existing mathematical model of the spatial vehicle/track dynamic system was taken as a theoretical model for calculation of interaction forces between the track and the vehicle. This model considered the track as a spatial structure consisting of beams (rails) rested on many separate rail supports (sleepers) of non-linear elastic-dissipative characteristics. The altered mathematical model considered the track inertia properties. The theoretical and experimental research, both in laboratories and in the field, made it possible to establish spatial rigidities of rail supports on wooden and reinforcedconcrete sleepers and nine types of rail intermediate fastenings allowed only for small radius curves. The predictive estimate of changes in the spatial rigidities of rail supports in operation was conducted. The numerical research into the influence of rail track structural characteristics, arrangement, maintenance and operational norms, operational terms, train operational modes for side wear, and rail damageability in small radius curves was conducted. The adequacy of the models and methods to solve the problems was confirmed by comparing the calculation results with the experimental data. The practical recommendations on the peculiarities of track arrangement and operation in small radius curves were developed; further they may help decrease the rail side wear up to 40 % and reduce damages through other defects.