Onboard energy storage for discontinuous, safer third rail DC electrified rail systems

A novel model has been created in order to investigate the use of onboard energy storage to remove the exposed conductor rail from stations in top contact third rail electrified systems and instead use an onboard energy storage system to power the train in to and out from the station with discontinuous electrification. Top contact third rail electrified systems are an alternative electrification method to overhead line equipment, however due to their exposed conductor rail there is a significant safety concern, despite being a potentially cheaper method of electrification. For example, in Great Britain (GB) the safety concerns have created a presumption against expansion of top contact conductor systems. Of the major injuries and fatalities caused by electrocution on third rail networks in GB, 33% of these incidents are recorded as having occurred at the station. The model is able to simulate the mechanical, electrical and energy storage requirements needed for this novel discontinuous application and is able to evaluate the energy draws, requirements and losses in the application. It is found that using an energy storage system can bridge 300 m gaps in the conductor rail within stations effectively with minimal impact on the timetabled journey time and, depending on the size of the energy storage system, showed a potential to reduce energy consumption by up to 10% compared to the fully electrified system. These results demonstrate that a discontinuously electrified system can be applied on DC third rail networks to improve passenger safety, with potential for future energy savings.