Finite element analysis of the lock stretcher bar in a railway switch

The lock stretcher bar (LSB) is an important component of some types of railway switches in which it plays a major and dynamic role in setting the switch for and guiding the trains to the proper route. If the LSB is damaged, deformed or broken then the switching operation cannot be completed. The work presented in this paper is an investigation into the performance of the LSB under several different operational and assembly conditions. Full three-dimensional finite element (FE) simulations have been conducted on an isolated LSB from a short, shallow depth, switch to investigate its performance under various deformations and loads. To validate the FE model, experimental work has been carried out and good agreement was obtained between the measured and computed data. The FE model was then used to obtain the safe envelop of the LSB’s operating range. Different proposed new design variations for the LSB have been tested in simulations and their structural performance has been compared with that of the existing designs with significant improvements identified.