Fatigue: identification, management and countermeasures

Abstract

Managing operator fatigue is a perennial challenge in any safety-critical industry that involves shiftwork. The 24/7 railway is no exception, with the UK industry having made considerable efforts at mitigating the risk of fatigue since the Clapham Junction accident of 1988. Whilst the causes and effects of fatigue are well documented, it still plays a part in a number of rail accidents, including 12 that have been investigated by the RAIB since it became operational in October 2005. In these investigations, the RAIB has identified several recurring concerns associated with monitoring, reporting and mitigating the risk arising from fatigue for rail workers – concerns which are shared elsewhere in the industry.

This paper presents a review of literature and practices in rail and other safety-critical industries, aimed at understanding barriers to reporting as fit for duty when possibly suffering from fatigue, as well as identifying and managing the accumulation of fatigue during a shift. The paper draws upon case studies from RAIB investigations to explain the mechanisms of fatigue, then describes fatigue management and monitoring from a historical perspective through to the current state of science on the subject. It discusses potential countermeasures to fatigue, and closes with potential lessons for the rail industry about techniques and technologies for detecting and managing fatigue.

Fatigue management has historically been controlled through limitations on working hours and constraints on roster scheduling. Efforts at incorporating scientific knowledge into this process, through biomathematical fatigue models, have met with mixed success. More recent guidance encourages a holistic approach to fatigue risk management, encompassing training and education as well as open reporting and fatigue monitoring.

Fatigue monitoring can take the form of fit-for-duty assessments, or ‘on-line’ monitoring during a shift. Various tools and techniques are available for each of these, including subjective reports, activity monitors, simple performance tests (often using mobile apps), behavioural monitoring or physiological metrics. However, the technological solutions are not currently at a level of maturity whereby they would be feasible or acceptable as a regulatory measure. There is thus no single, reliable and practical solution to this problem.

Countermeasures to fatigue only offer temporary respite and should really be seen as a last resort; the only genuine cure is restorative sleep. However, the use of napping strategies (where practicable) and tactical use of caffeine are the most widely adopted countermeasures. There is also research to suggest that blue light can stimulate alertness and may have more beneficial effects than caffeine. More research is needed on the effects and side effects of both caffeine and blue light.

But these detection technologies and countermeasures are essentially reactive – they are short-term fixes for an individual who is already fatigued. Whilst such interventions can form part of a fatigue risk management system (FRMS), ultimately, the effective management of fatigue should be preventative. Rostering, workforce engagement, reporting and organisational culture should all be geared towards encouraging workers to get enough sleep.

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Identifiers

ORCID for Mark Young: orcid.org/0009-0001-2594-453X

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