Short wavelength rail defects or short-wave effects of rail have a significant influence on the system behaviour of railways. The influence of additional dynamic loads due to short-wave effects on component wear and the general quality behaviour of track is shown by several research papers. However, the described effect cannot yet be quantified comprehensively. This paper attempts to fill this gap. With the help of extensive data analysis, we can show that short-wave effects lead to a track geometry that is up to 50% worse than on average. Furthermore, we show examples illustrating the influence of untreated welded joints on the development of isolated defects of the track geometry. A detailed in-depth analysis of sections with different boundary conditions finally shows that short-wave effects have a significant influence on track geometry if the amplitude of the effect exceeds 0.15 mm. This value can be recommended as a threshold value in Austria and as a reference value in other countries.

Condition assessment and maintenance planning of railway infrastructure is a prerequisite for safe and reliable train operation. As the loads are constantly increasing, condition assessment of the track must also be further developed. Existing methods can describe the condition of the track well in many cases, but they will reach their limits with faster deterioration processes and shorter time windows for inspection and maintenance, both associated with higher loads. This development can only be countered with an increased understanding of the system and the associated better planning of component specific measures. Among others, short-wave effects of the track need to be considered. The aim of this paper is to demonstrate the possibility of describing short-wave effects with an already existing data source. Insulated rail joints, welding joints, switch components, but also rail corrugation of different wavelengths and squat can be detected, evaluated and monitored by a measuring system based on optical distance meters. These assets and wear phenomena form essential parts of track asset management, but still are not described sufficiently by established methods. Although the so-called rail surface measurement system has been installed on the main Austrian measuring car for years, its full potential could not be exploited due to insufficient positioning accuracy. The method presented in this paper intends to change that. This allows for a holistic assessment of track condition when planning maintenance activities.

Managing head checks is a crucial task for an infrastructure manager as in case of deep cracks, rails can break and, thus, accidents might be the consequence. Many infrastructure managers use vehicle-mounted eddy-current testing for detecting cracks. This is sufficient for guaranteeing safe railway operation in applying a reactive maintenance regime removing cracks of a pre-defined depth. Moving this towards a predictive maintenance regime is only possible through assessing the crack growth. Establishing a stable deterioration function needs a sound data basis including a proper re-positioning of the test results of consecutive testing campaigns. This paper presents the results achieved from analysing the eddy-current testing campaigns of 10 years on a main line of the Austrian railway network and calculating a crack growth function as regression to field data. While it is possible to derive stable functions, the testing frequency needs to be shortened in order to move further to predictive maintenance.

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In this paper, the potential of an already existing measurement system for the condition assessment of insulated rail joints is shown. The system properties of the so-called rail surface measurement system are described and the potential of systematic data analysis is addressed. The measured short-wave range and the high sampling rate offer the possibility of adding further facets to the existing track condition assessment. The data source is particularly suitable for evaluating shortwave effects, which were previously difficult to describe. With the help of a positioning algorithm it becomes possible to evaluate isolated rail joints regarding their quality development over time. It can be shown that insulated rail joints deteriorate in a super linear manner. In order to reduce the negative influence on the quality behaviour of the entire track, intervention thresholds for a preventive maintenance regime have to be defined. Using technical-economic assessments, these intervention thresholds can be defined in a way to ensure undisturbed railway operation with the lowest possible life cycle costs.