Refurbishment of ballasted track systems; the technical challenges of quality and decision support tools

The life of ballast is dependent upon a number of factors mainly traffic loading, drainage, contamination and is clearly related to intervention levels and installation quality standards. The use of mechanised ballast replacement techniques has developed over the last 30 years ranging from intrusive and non-intrusive processes. UK national policies have now recognised refurbishment of ballasted systems as an economic alternative to complete renewal especially in locations of switches and crossing (S&C) layouts. There are ever increasing technical challenges associated with the formation and ballast layer interface which relate to localised track quality and the route based longitudinal integrity of these refurbished discrete locations. This paper identifies current best practice in terms of machinery and the recent specialist applications. Also discussed are the complexities of vehicle and product acceptance and introduction including the development of complementary decision support tools.