Energy harvesting from the vibrations of a passing train: Effect of speed variability

This paper builds on a previous study which investigated the amount of energy that could be harvested from the vibration induced by a passing train using a trackside energy harvester. In that study, the optimum parameters of the device were determined for a train passing at a particular speed. However, the effect of the train speed variability on the amount of energy harvested was not explored. In this paper a study is thus undertaken to determine this effect using experimental data from train passages at a site in the UK. Furthermore, a model is developed to investigate the optimum design parameters of the energy harvester when trains pass by at slightly different speeds. This is then validated using the experimental data. It is found that, provided the variability in the train speed is less than about 1% from the nominal speed, then a harvester tuned so that its natural frequency matches one of the trainload dominant frequencies at the line speed is a reasonable design condition.