Author(s)

ALEJANDRO ORTEGA, SIMON BLAINEY & JOHN PRESTON

Abstract

Over the last twenty years, the railways in Britain have seen rapid growth, with patronage doubling and the level of train service increasing by 50%. However, these successes have also led to challenges. In particular real unit costs are estimated to have increased by 50%, with particularly marked increases in infrastructure renewal and enhancement costs. Against this background, the University of Southampton have been leading the Track 21 and Track to the Future projects, funded by the Engineering and Physical Sciences Research Council. These projects are assessing how to make ballasted track systems more durable given higher traffic levels and how to reduce the costs of maintenance and renewal.

Track 21 considered a number of engineering interventions of which this paper focusses on one, under sleeper pads (USPs). The cost implications of this intervention are assessed for the South West Main Line using an industry-specific model, VTISM (vehicle track interaction strategic model), adapted in two ways. First, the results of laboratory experiments from specialist test rigs are incorporated into the model. Secondly, the wider effects of increased reliability, improved ride quality and reduced vibration are also considered within a cost-benefit analysis framework. It is found that USPs can lead to substantial financial savings and, depending on assumptions concerning noise impacts, are likely to have substantial wider social benefits.

Keywords

CBA, maintenance costs, under sleeper pads