Under sleeper pad (USP) is a new elements in the tracks in the Czech Republic. The trial track section with a turnout in which are installed bearers with USP has been constructed in the Planá nad Lužnicí railway station (IV. railway corridor: Praha – České Budějovice – Linz) in 2007. The section comprises of the turnout and transition zones with USP and an appropriate comparative section. The total length of track with under sleeper pads is 205 m, the length of the comparative section is 200 m. The aim of USP application is to homogenize track stiffness and as a consequence to improve the track quality.
The trial track section, a methodology of a track geometry parameters’ monitoring (precise levelling and track measuring car data) and a measurement evaluation are described in the article. Rail top levels of the tracks are monitored through a precise levelling. Following parameters from track recording car are monitored: alignment of track, longitudinal level and cant. Deviations from designed position, standard deviations of the parameters and track twist are calculated. Measurement and calculated data from both the precise levelling and track recording car are compared. Conclusions related to the USP influence on the track geometry parameters quality are summarized in the end of the article.

monitoring, track geometry parameters, trial track section, turnout, under sleeper pad