Earthworks Renewals Cost and Volume Transparency - Targeted Assurance Review - May 2021

Earthworks are the 20,000 miles of earth and rock slopes along the railway. Earthworks are the most variable of all Network Rail’s asset types. For example, replacing a section of track in one part of the country will involve similar methods and costs, as replacing the same length of track in another part of the country. However, renewing two different earthworks sites will involve completely different geology, drainage, slope heights or steepness, neighbouring land uses and many other variables.  Network Rail report the total number of renewals they deliver and the total cost but, because of the variability between different sites, ORR have no way of knowing whether a high total cost is because Network Rail were extremely inefficient, or whether these sites were just more challenging than the average, or maybe Network Rail have chosen to install very high quality components to last longer or to withstand climate change. So, ORR undertook this Targeted Assurance Review to look at a sample of individual projects, to examine how much they varied and to identify the key factors driving high or low costs.