An Evaluation of Redundancy Concepts for Fault Tolerant Railway Track Switching

Railway track switching provides necessary flexibility to a rail network, but also introduces many single points of failure. Other industries have resorted to redundancy to provide the fault tolerance necessary to achieve specified safety and operational goals in similar critical systems, yet this approach has not yet been applied to track switching. This paper explores several system concepts for redundancy in track switching, and attempts a rudimentary cost/benefit analysis of each. Mechanical design is not considered, the paper being a feasibility study only. Finally, concept performance is evaluated in a case study at Derby Midland station (UK). The results show that providing redundancy which utilises only existing technology demonstrates some gains in operational availability. However, it is unlikely to be cost effective, and for redundancy in track switching to be a realistic prospect, novel designs and technologies may be necessary.