Extending emergency repair response times for railway track switches through multi-channel redundancy of functional subsystems

A novel track switch concept has been developed at Loughborough University, which allows parallel-channel, fault-tolerant functions for the first time. This paper demonstrates, through mathematical modelling, real-world data and conservative assumptions, that using a multi-channel, fault-tolerant switching concept can allow an increase in switch availability over baseline scenarios. Performance of four existing switch types is analysed for baseline performance using field data. Multi-channel architectures are then analysed across a range of reactionary maintenance regimes. Availability measures are obtained which show the range of possible switch availability against maintenance response times. The most significant improvements occur when maintenance practice is also revised, the novel system offering the option to run to subsystem failure and remain functional. Results indicate that for multi-channel installations, gains in system availability are possible even when emergency response times are set orders of magnitude longer than currently achieved, indicating a signifi cant reduction in ongoing maintenance commitment. The work also demonstrates that the particular choice of subsystem architecture is of low significance.