The condition monitoring and assessment of railway infrastructure are vital tasks of infrastructure managers. Economically and technically optimal maintenance measures and strategies are planned and executed based on the condition assessments.The present work examines the potential of fibre optic cables, which are already installed in cable troughs alongside railway tracks, for railway infrastructure condition monitoring and assessment. Distributed Acoustic Sensing (DAS) transforms the fibre optic cable into a linear sensor detecting all structure-borne sound waves and vibrations. The results presented demonstrate the applicability of DAS for infrastructure condition monitoring. The current condition as well as the emergence or deterioration of isolated track defects over time can be assessed and quantified. Furthermore, both the quality of maintenance work such as tamping, and its effect can be evaluated. DAS enables data-based condition monitoring of turnouts and insulated rail joints. This permits to draw conclusions on the current condition of assets and sections. This work provides a basis for future developments and shows that a holistic and permanent condition monitoring, as well as condition assessment of the railway infrastructure, can be achieved utilising DAS.weiterlesen