Delivering Customer Services Today with Assets from Yesteryear: Network Rail's Approach to Managing Its Ageing Structures Assets

Abstract

Network Rail runs, maintains and develops Britain's rail system, the oldest system in the world and one of the busiest. Network Rail's vision is to meet the needs of its customers safely, reliably and efficiently by delivering one of the leading rail systems in Europe. There are 80,000 assets within the structures portfolio comprising bridges, tunnels, culverts, retaining walls and coastal, river and estuarine defences. The assets are long-life, on average 125 years old, complex and heterogeneous. Their construction at a time of rapid expansion of the railway during the second half of the nineteenth century, often by competing railway companies, means that design and construction records are few, as are reliable and accessible maintenance records prior to 2000. This combination represents a significant challenge in predicting the long term behaviour and underlying risk levels of this asset group. The paper describes the development of a risk-based structures asset policy to drive maintenance and renewals interventions over the next 35 years. The asset policy sets objectives, targets and measures, aligned to corporate goals, within the service level categories of capability (the ability of the assets to bear load, pass gauge and allow line speed), safety and availability. Modelling was used to demonstrate that attainment of the targets, through the prescribed interventions, will deliver an acceptable level of risk for the asset sub-groups and can be achieved sustainably at lowest whole life cost.