Fatigue management

Introduction

Train drivers, regulators and signallers or track maintenance workers, for example, are making safety-critical decisions every day. Thus, the consequences of a fatigue-related error in a rail setting can be catastrophic for both operational and occupational safety. They are human beings with natural and known limitations. Falling asleep is the only natural (and best) remedy against fatigue, and very often this is not possible at work. So, like any other category of risks, fatigue must be managed by the organisation and not only by the individuals.  

Fatigue can be defined as a decreased capacity to perform mental or physical work, with involuntary physiological performance decrements and cognitive impairment, due to inadequate restorative sleep, time of day, length of the waking period, lack of breaks, nature of the activities, etc. 

Relevance to rail

Fatigue is a major cause of ‘distraction’, hypo-vigilance (even micro-sleeps), performance variability and impairment.  Fatigue is also known to alter perception, reaction and reasoning times, and to reduce communication skills because of irritability and disengagement, etc.  

Fatigue can also have long-term health impacts and influence absenteeism. Yet, in many railway organisations, staff are in short supply, take a long time to recruit and train, and are older on average (and therefore more susceptible to fatigue in general). 

When this human and organisational factor is tracked after incidents, recent studies have shown that the railway sector, like other high-risk industries, is not unaffected. For example, in a RSSB report (2015), Bowler & Gibson calculated that the prevalence of fatigue within 246 high risk railway incidents was about 21%.  

Approaches and models

Fatigue risk management (e.g. ORR, 2012) can include several layers of controls and mitigations across the organisation: 

• The more predictive and proactive ones, such as: improving the policies, the design of hours of work, the breaks and the high/low demanding activities, influencing commuting and sleep conditions, developing fatigue awareness, reporting and assessments, workers and supervisors (first line management) education and training, managing individual differences and impact on health, etc.  
• The more reactive and adaptative ones, such as: improving the analysis of the variabilities and errors, the monitoring of the risk control measures (see predictive and proactive layers), promoting and resourcing the investigation of all incidents with an organisational open-mindedness, implementing and verifying the corrective actions, etc.  

• The adequate involvement of staff (including leaders at all levels), contributions of Health and Safety experts and regulations, and the railway national authorities recommendations (e.g. NIB investigators, NSA auditors), can also be fruitful in the professionalisation of fatigue risk management. 
• Technical devices exist but there is no panacea and they still need further testing and field validation.