Comparison of concepts for possible future train integrity monitoring systems

In the railway sector, experts anticipate considerable reductions of costs by supplanting conventional infrastructure equipment with digitalised solutions. As a consequence, distances between trains can be reduced and track capacity increased, correspondingly. The necessity to protect consecutive trains from lost vehicles of preceding trains leads to the need to monitor continuously the completeness of a train, which is also referred to as the integrity of a train, as intended in the European Train Control System (ETCS) level 3. The development of a safe corresponding train integrity monitoring system (TIMS) for Europe is still a challenge as many freight trains lack a continuous electrical line. The purpose of this work is to give a short scientific overview of the main concepts for possible future TIMSs. For this, the publication is based on the work of the authors for the Swiss Federal Railways within the smartrail 4.0 industry programme in the year 2018. At that time, they conducted a study on approaches to TIMSs. As a result, they researched more than 600 publications. Now, in 2022, the authors realised an update of that study. In this publication, the selection of concept classes for TIMSs grounds on that research work. The authors conclude that train integrity monitoring in Europe is currently based on axle counters and track circuits, so these two concept classes were chosen. In addition, the authors identified three main classes of possible future TIMSs: distributed acoustic sensing, end-of-train device and digital automatic coupling.