Optimising the power upgrade solution of the Sub Surface Railway

The London Underground Sub Surface Railway (SSR) is due for a major upgrade by 2018. The upgrade will include the procurement of new rolling stock, a new signalling control system, a significant increase in service frequencies, and a significant power supply infrastructure upgrade. Investigation of energy efficiency measures, such as optimal rolling stock power with use of coasting in the run profiles, higher supply voltage, and conductor rail of lower resistance, allowed the system wide whole life costs to be significantly reduced with no reduction in customer benefits. The optimisation study undertaken achieved cost savings of £25m in capital expenditure and £70m in whole life costs, as well as a 20% energy and CO2 reduction, for the same improvement in customer journey time performance post upgrade. The paper describes in detail how the optimisation study was performed.