Installation of under sleeper pads on ballasted railway tracks: An economic analysis of their potential implementation

Abstract

This study examines the economic impact of installing under sleeper pads in two different routes in the UK: the London-Portsmouth line and a section of the East Coast Main Line. The Portsmouth line is a typical suburban route with a high proportion of commuters whereas the East Coast Main Line is a higher speed line with less users and more distance between stations. The cost implications of this intervention are assessed through a stochastic application of cost benefit analysis underpinned with a sensitivity analysis. Using an industry-specific model, vehicle track interaction strategic model, as well as the results of laboratory experiments conducted at the University of Southampton, we are able to offer a set of conclusions. Increased reliability, improved ride quality and reduced vibration are important benefits for the users, higher in total terms on the Portsmouth line than on the East Coast Main Line, but smaller when the comparison is made on a per capita basis. In other words, the investment brings a higher absolute efficiency gain for the Portsmouth line but a higher relative efficiency gain for the East Coast Main Line. It is found that under sleeper pads can lead to substantial financial savings; these are higher for the East Coast Main Line than the Portsmouth line. Finally, depending on assumptions concerning noise impacts, under sleeper pads are likely to have substantial wider social benefits; these are much higher for the Portsmouth line than the East Coast Main Line. Although these conclusions are based on a UK case study, they could be applicable to any railway operation in a developed region facing high maintenance costs and growing demand.