Auxiliary plant & equipment for station and tunnel services

The intention of this paper is to give an understanding of the legislation and guidance that must be complied with in designing the power systems for the provision of station and tunnel services into railway infrastructure. In so doing detail of the other auxiliary equipment and systems that must be provided to comply with this legislation and guidance plus operating requirements and passenger expectations is provided together with the impact that they impose on the power supply arrangements. It aims to show that consideration needs to be given to the availability and reliability of the power system and to its usage, i.e. whether during normal, degraded, abnormal or emergency train and station operational modes, more than to its traditional features of load demand and utilisation. In establishing these criteria explanation is provided of the performance criteria surrounding the identified auxiliary plant and equipment which in turn passes requirements onto the power supply provisions. Finally approaches to establish these performance criteria are suggested and outline of power supply arrangements that have been proved in practice are provided. A closing view of future demands on the above identified systems is also given for anybody now or imminently commencing on such a design task.