ABSTRACT
Track geometry is generally defined in terms of track gauge, cross level, alignment, and vertical surface profile. This chapter focuses on the present status of track geometry measurement and the applicable geometric standards in South Africa. A step is taken towards addressing the requirements with respect to a vehicle related description of the track. Due to the present lack of true longitudinal track profile measurements, an algorithm is used to estimate the Power Spectral Density values of the various geometric track irregularities. To conclude, some observations with respect to the stiffness of the track sub-structure are given and future work is recommended. Power Spectral Density (PSD) values of the track geometry are generally used. The problem is that such information is not available for South African track geometry. To improve the accuracy of the input into the dynamic model, improved track geometry measurement techniques have to be put in place.
