Physiological Measurements for Real-time Fatigue Monitoring in Train Drivers: Review of the State of the Art and Reframing the Problem

The impact of fatigue on train drivers is one of the most important safety-critical issues in rail. It affects drivers’ performance, significantly contributing to railway incidents and accidents. To address the issue of real-time fatigue detection in drivers, most reliable and applicable psychophysiological indicators of fatigue need to be identified. Hence, this paper aims to examine and present the current state of the art in physiological measures for real-time fatigue monitoring that could be applied in the train driving context. Three groups of such measures are identified: EEG, eye-tracking and heart-rate measures. This is the first paper to provide the analysis and review of these measures together on a granular level, focusing on specific variables. Their potential application to monitoring train driver fatigue is discussed in respective sections. A summary of all variables, key findings and issues across these measures is provided. An alternative reconceptualization of the problem is proposed, shifting the focus from the concept of fatigue to that of attention. Several arguments are put forward in support of attention as a better-defined construct, more predictive of performance decrements than fatigue, with serious ramifications on human safety. Proposed reframing of the problem coupled with the detailed presentation of findings for specific relevant variables can serve as a guideline for future empirical research, which is needed in this field.