Evaluating the applicability of multi-sensor equipped tamping machines for ballast condition monitoring

•A novel methodology to monitor railway track ballast condition is introduced.•Measurements from a sensor-equipped tamping machine are analysed.•Simultaneously, the condition of the bedding on the tamped sections is evaluated.•Tamping machine measurements show strong dependence on track ballast condition. Ballast is a key component of most railway tracks and fulfils crucial tasks. The strong forces induced by train operation, however, wear the stones, and in combination with external pollution the condition of the bedding gradually deteriorates. Track alignment issues arise as a consequence and these are usually corrected by use of tamping machines. The importance of a functioning ballast bed implicates the necessity for sophisticated condition monitoring. A novel approach for addressing this need is presented here. The tamping unit of a high-performance tamping machine has been equipped with multiple sensors, which measure various parameters during every tamping process. A set of recorded data is analysed and compared with the prevailing ballast condition, which is evaluated using proven methods. The results verify that the measurements correlate with the condition of the bedding, thus confirming the assumption that sensor equipped tamping units allow conclusions regarding the condition of track ballast.