Introduction of new systems for evaluation of ballast bearing capacity

The stiffness assessment of the trackbed should include an assessment of ballast, subballast and formation (e.g sub-ballast depth, groundwater profile). Furthermore, a lack of a systematic monitoring brings to the impossibility to produce an effective long term track management system, by allocating budget where emergencies come. Consequently, there is an increasing importance in obtaining a consistent relative measure of trackbed stiffness in the physical and time restrictions applicable on live track for assessing potential maintenance requirement and subsequent design of countermeasures. Moreover, in the case of local railway track with narrow gauge, the use of the traditional high speed track monitoring systems is not feasible. This paper details a site investigation comprising Ground Penetrating Radar (GPR), Light Weight Deflectometer (LWD) and falling weight deflectometer testing. These systems are currently used in road pavement maintenance where have shown their reliability and effectiveness. Application of such Non Destructive Tests in railway maintenance are promising but in the early stage of investigation. In the paper literature review and trial site testing are used to identify Strengths, Weaknesses, Opportunities, and Threats (SWOT analysis) of the application of GPR and LWD for the assessment of trackbed and superstructure conditions presenting also an in field experience and tracking the direction of future work.