Adequate railway track condition is a prerequisite for safe and reliable railway operation. Many track quality indices (TQIs) have been developed with the aim of assessing the track condition holistically. These indices combine measurement signals of some or all relevant geometry parameters with different mathematical models. In this paper, a selection of important TQIs is evaluated. Using measurement data of a five kilometer track section, the indices are calculated and their properties are discussed. This study reveals that all indices exhibit drawbacks to varying degrees. As a consequence, a new index has been developed—the track quality index of Graz University of Technology (TUG_TQI). Its favorable characteristics are presented by means of the above-mentioned test section. The TUG_TQI combines all relevant track geometry parameters, which are normalized beforehand to eliminate over or underrepresentation of different parameters. Thus, the index reliably describes the overall geometrical track quality.

The deterioration of ballast and the consequences of weak subsoil increase the need for track maintenance. These problems reduce the service life of tracks, and a higher maintenance budget is required. This paper introduces an innovative method for evaluating the condition of the ballast and the subsoil. Fractal analysis of the vertical track geometry enables infrastructure managers to determine the root cause of track irregularities by quantifying the wavelength characteristics of the common track geometry data. This methodology determines whether the ballast or the substructure condition is the cause of poor track quality. Fractal analysis has been carried out to date on the main network of the Austrian Federal Railways, which comprises some 4000 km of track, as well as within the network of Suisse Federal Railways (∼5000 km). Additionally, several lines in the United States (Amtrak), Belgium (InfraBel), and Denmark (BaneDanmark) have been evaluated. A detailed validation process has been carried out to investigate different characteristics and their correlation to the in situ behavior of the track. This research is now showing promising results after being cross-checked with historical data and compared to the implemented maintenance measures. On-site inspections have confirmed the evaluated component-specific condition.

Current railway track work machinery is mainly operated with diesel fuel. As a result, track maintenance of Austrian Federal Railways (OeBB) amounts to nearly 9000 t CO₂ equivalent per year according to calculations from Graz University of Technology. OeBB’s total length of railway lines only accounts for 0.56% of the world’s length of lines. This indicates huge potential for mitigating greenhouse gas emissions considering the need for track maintenance worldwide. Environmental concerns have led to the introduction of alternative drives in the transport sector. Until now, R&D (Research & Development) of alternative propulsion technologies for track work machinery has been widely neglected. This paper examines the possibility of achieving zero direct emissions during maintenance and construction work in railways by switching to alternative drives. The goal is to analyze alternative propulsion solutions arising from the transport sector and to assess their applicability to track work machinery. Research results, together with a calculation tool, show that available battery technology is recommendable for energy demands lower than 300 kWh per construction shift. Hydrogen fuel cell technology is an alternative for energy demands higher than 800 kWh. For machinery with energy requirements in between, enhancements in battery technology are necessary and desirable for the coming years.

Today’s railway transport is built upon high-performance infrastructure. Cost-effective yet sustainable infrastructure presumes tracks with a precise and durable geometry. At ballasted tracks, the geometry is created and restored through tamping machines, which position the track panel and compact the ballast beneath the sleepers. It is commonly agreed that the ballast compaction plays an important role in the long-term stability of the track. Yet, there is no method available which allows a direct correlation between the compactness of the ballast and the stability of the track geometry. Available studies either model track behaviour without considering the bedding, or analyse ballast compactness locally while disregarding its influence on the track geometry. This paper presents a new methodology which establishes a relation between these two topics—ballast compaction during tamping and subsequent track behaviour. A state-of-the-art tamping machine has been equipped with an experimental measurement setup, constantly recording relevant data during every tamping process. These data can be used to derive an indication for the achieved compaction under every sleeper. Utilising the tamping machine’s internal measuring system for track geometry documentation, every tamping process (every sleeper) is assigned to the precise position along the track. The data set is merged and synchronised with regular track geometry measurements of the infrastructure manager. The result is a comprehensive data set which allows precise analyses between tamping machine measurements and track behaviour. This data set provides the foundation for future research, aiming towards a better understanding of the tamping process and its influence on the quality and durability of the established track geometry.