No abstract

Ballast, rails and sleepers form a quasi‐elastic track system. When the deformations exceed the elastic limit of the system and the track is no longer lying in its correct position, precautions have to be taken. During a technical track examination several parameters are measured. Should the operational tolerance values of these parameters be exceeded, track maintenance needs to be conducted. Track maintenance includes levelling, lifting, lining and tamping of the track, which is performed by a tamping machine, where the tamping tines penetrate the ballast and compact it beneath the sleeper. For the purpose of this research project, a tamping machine was equipped with a number of strategically positioned sensors in order to perform the in‐situ measurements required to describe the interaction of the tamping tines with the ballast and its compaction beneath the sleeper. With a special emphasis on the energy transferred into the ballast and alteration of ballast stiffness during compaction, conclusions concerning efficiency of the tamping process in different ballast conditions are made and presented.

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.

Der Zustand des Gleisschotterbetts ist einer der wichtigsten Faktoren für den sicheren und ökonomischen Betrieb von Gleisanlagen. Um den idealen Zeitpunkt für die Schotterreinigung oder die Erneuerung des Schotters zu finden bzw. auch um die Gebrauchstauglichkeit und Leistung über den gesamten Lebenszyklus zu erhöhen, ist die Kenntnis über den Schotterzustand bzw. über die Abnutzung des Schotters von größter Wichtigkeit. Das Gleisstopfen als zentraler Prozess der Gleisinstandhaltungsarbeiten beeinflusst die Instandhaltungsintervalle maßgeblich und ist notwendig für die Wiederherstellung der korrekten Gleislage. Während des Stopfvorgangs bilden die Stopfpickel ein dynamisches Interaktionssystem mit dem Gleisschotter. Die translatorische Beistellbewegung wird durch die dynamische Anregung der Pickel überlagert, um den Gleisschotter unterhalb der Schwellen bestmöglich zu verdichten. Die genannte Interaktion wurde an verschiedenen Standorten in Österreich messtechnisch erfasst und dient als Grundlage für einen Vergleich mit den Ergebnissen eines neu entwickelten, semi‐analytischen mechanischen Modells. Schlussfolgerungen bzgl. des unterschiedlichen Verhaltens und Widerstands gegen weitere Verdichtung von abgenutztem und neuem Schotter werden getroffen und im vorliegenden Beitrag diskutiert.

Ballast is a key component of most railway tracks. The ballast bed must cope with high demands while fulfilling crucial tasks. Wear and contamination cause the condition of the bedding to deteriorate, which is accompanied by a loss of its proper functioning. Consequently, track alignment issues arise, which are typically corrected by tamping the affected areas. This study presents a new approach to assess the condition of the bedding. The tamping unit of a high-performance tamping machine has been equipped with an array of sensors which measure various parameters during every tamping process. A set of recorded data is analysed and compared with the prevailing ballast condition of the tamped sections, which is evaluated using proven methods. The results indicate a strong correlation between the tamping machine measurements and the condition of the bedding, which shows that tamping machines can be used to monitor the track ballast condition.