Naloga obsega pregled elementov zgornjega ustroja železniške proge, meritve parametrov in analizo vpliva geometrijskih elementov na vrednosti parametrov. V prvem delu naloge je predstavljen potek degradacije zgornjega ustroja. Opisani so elementi, ki sestavljajo zgornji ustroj in predstavljene zahteve, ki jih za posamezni element določajo standardi in pravilniki. V drugem delu naloge so predstavljeni merilni vlaki, ki izvajajo meritve na slovenskem železniškem sistemu. Predstavljeni so vlaki, ki merijo stanje tirnice in vlaki, ki merijo stanje tira. Za posamezne merjene parametre tira so opisane zahteve, ki jih določa Pravilnik o zgornjem ustroju železniških prog (2010). V zadnjem delu naloge so analizirane meritve, ki so se izvajale na železniški progi št. 50 Ljubljana–Sežana–d.m., na odseku Ljubljana–Postojna. Na splošno je predstavljena geometrija odseka Ljubljana–Postojna ter druge značilnosti na obravnavanem odseku. Analiziran je vpliv geometrijskih elementov in elementov zgornjega ustroja na napako tirne širine, vegavost in razvoj posedkov. This thesis presents railway track components, track measuring and analysis of track components and it’s influence on track degradation. First part of thesis presents degradation of track and description of track components. Special requirements that are defined by standards and regulations are described for each track component. Second part of thesis presents measuring trains that do measuring on Slovenian railway system. Measuring trains that are represented can measure conditions of rail and conditions of track. This part also describes the regulations for measured parameters that are required with Pravilnik o zgornjem ustroju železniških prog (2010). The last part of thesis describes the analysis of measured parameters on railway line number 50 Ljubljana–Sežana–d.m. between Ljubljana and Postojna. The geometry and other characteristics of line no. 50 from Ljubljana to Postojna are represented. The effects of superelevation, lateral acceleration and curve radius on track gauge are represented. It is checked how the average track gauge, rail twist and settlements develop depending of curve radius.