Model for track degradation due to geometry defects

Najpogostejši vzroki za degradacijo tira so neenakomerno posedanje tira zaradi nehomogenosti podlage, neustreznega vzdrževanja, slabega stanja zgornjega in spodnjega ustroja ipd. Pri napovedovanju degradacije tira moramo vedeti, kdaj bodo mejne vrednosti geometrijskih parametrov tira prekoračene, da se lahko odločimo za pravočasno učinkovito načrtovanje vzdrževalnih in obnovitvenih del ali za druge ukrepe, ki zagotavljajo varnost železniškega prometa. Namen magistrskega dela je preučiti najpomembnejše modele degradacije tira zaradi geometrijskih napak, izbrati model, ki bi bil primeren za uporabo na območju Slovenije, in ta model preveriti na praktičnem primeru izbranega progovnega odseka. Glede na razpoložljive podatke o prometnih obremenitvah po posameznih progovnih odsekih in podatke o merjenju tira z merilnim vlakom sta bila najprimernejša za uporabo v slovenskem okolju avstrijski in švedski model degradacije tira. Avstrijski degradacijski model je primeren predvsem za napovedovanje degradacije tira zaradi posameznih geometrijskih napak v odvisnosti od začetnega stanja kakovosti tira in prometne obremenitve. Švedski degradacijski model pa obravnava geometrijsko degradacijo tira v odvisnosti od standardne deviacije vzdolžnih višinskih napak in standardne deviacije smernih napak leve in desne tirnice. Ugotavljanje standardne deviacije napak je namreč z uveljavitvijo tehničnih specifikacij o interoperabilnosti postalo obvezno merilo za oceno geometrijske kakovosti tira tudi v Sloveniji. Uporabnost obeh modelov je bila preverjena na praktičnem primeru na novo obnovljenem progovnem odseku Gornje Ležeče–Divača in na uravnanem progovnem odseku Ljubljana–Brezovica, ki je bil obnovljen pred 36 leti. Degradacijo tira smo po zadnji strojni regulaciji leta 2012 spremljali do leta 2015. Raziskava je pokazala zelo dobro ujemanje izmerjenih podatkov na terenu z rezultati, izračunanimi s predlaganimi modeli.The most common causes of degradation of the track are uneven settling of the track due to inhomogeneity of the base, inadequate maintenance, poor state of the upper and lower structure, etc. In predicting the degradation of the track we need to know when the limits of the geometric parameters of the track are exceeded in order to decide in due time for effective planning of maintenance and renovation work and for taking other measures to ensure railway safety. The aim of this master’s thesis is to investigate the most important models of track degradation due to geometry defects, select a model suitable for use in Slovenia, and test this model in practice along a selected section of railway line. Based on the available data on traffic loads by individual rail sections and data on the measurement of the track with a measuring train, the Austrian and Swedish models of degradation of the track were found to be the most suitable for use in the Slovenian context. The Austrian degradation model is particularly well suited for predicting degradation of the track due to various geometric errors, depending on the initial state of the track quality and traffic load. The Swedish degradation model addresses the track geometry degradation as a function of the standard deviation of the longitudinal level defects and standard deviation of the right and left alignment defects. With the introduction of technical specifications on interoperability, determination of the standard deviation of defects has become a mandatory criterion for assessing the geometric quality of the track in Slovenia as well. The applicability of both models was tested in practice along a relatively new section of track between Gornje Ležeče and Divača and along a section of track between Ljubljana and Brezovica that was renovated 36 years ago. Degradation of the railway track was monitored after the last regulation by tamping machine in 2012 until 2015. The research showed a very good correlation between data actually measured and the results calculated using the proposed models