Working patterns - fatigue


Working patterns can create safety risks if they are not properly planned and controlled.

Hours of work and other conditions of service are matters for agreement between employers and staff, but it is vital that working patterns are designed to reduce risks from fatigue as much as is practical.

This page outlines why the rail industry needs to take staff fatigue seriously, and provides links to some key guidance including our publication 'Managing Rail Staff Fatigue'.

What is fatigue?

Collapse accordion Open accordion

There are several types of fatigue, but we are particularly concerned with mental fatigue. Mental fatigue can be caused by prolonged working, heavy workload, insufficient rest and inadequate sleep.  Continual mental effort and attention on a particular task can also contribute to fatigue. It is important that workers are not fatigued when their work is critical to safe operation, such as work done by drivers, signallers and maintenance staff. There are obvious safety risks for railway workers and others if this happens. It must be effectively managed.

Why is fatigue a problem?

Collapse accordion Open accordion

Fatigue reduces workers' mental alertness and can affect performance. Errors caused by impaired concentration, perception, judgement or memory are more likely. People may become more impatient. Ultimately this can lead to drowsiness or falling asleep.

Fatigue may cause or contribute to dangerous errors. A signal may be misread or overlooked, an important instruction or message may be misunderstood and staff will be more likely to make an error.

Examples of fatigue

Collapse accordion Open accordion

  • a driver moves away forgetting that permission has not been given;
  • a track worker carrying out maintenance or renewal work fails to complete necessary checks or procedures before finishing a job
  • a signaller sets an incorrect route or gives an incorrect message;
  • a track worker falls asleep on the motorway while driving home after working all night to complete the job.

What causes fatigue?

Collapse accordion Open accordion

Fatigue can be caused by a number of factors including:

  • the job design, the workload and the working environment;
  • the length and timing of shifts (e.g. long night shifts, shift start times);
  • the nature of the changes between shifts (shift rotation), especially backward rotation;
  • the balance in concentration and stimulation in the work activities being undertaken;
  • when and how workers travel to and from work;
  • insufficient rest breaks both between shifts and within a shift; and
  • the time of day.

How should it be managed?

Collapse accordion Open accordion

Fatigue management should include:

  • development and implementation of appropriate policies;
  • design of working patterns and shift rosters;
  • risk assessing changes to working patterns and rosters;
  • monitoring levels of fatigue; and
  • fatigue education.

What legislation covers fatigue and working hours?

Collapse accordion Open accordion

All employers have general duties under the Health and Safety at Work Act and the Management of Health and Safety at Work Regulations to control risks from fatigue. If their staff carry out "safety critical" work, they have additional fatigue management duties under Regulation 25 of the ROGS Regulations.

Additionally, the EC's working time directive covers the number of hours railway employees can work. From 1 August 2003, working time regulations entitle railway workers (work no more than?) to an average 48-hour working week, including sufficient rest periods. Workers can choose to work for longer than the average 48 hours per week if they wish, although employers cannot require them to do so.

More detailed information can be found in our publication 'Managing Rail Staff Fatigue'.

Guidance on fatigue

Collapse accordion Open accordion

Am I likely to be too fatigued?

It can be difficult to predict how fatigued you’ll be throughout your shift - you may feel OK when you wake up, or when you book-on, but it’s hard to tell how tired you’re likely to become later.  You may underestimate your risk of becoming fatigued, and the serious effects this might have on your own safety and on other people’s safety.  

To help with these decisions RSSB project T1130 on Developing and trialling fitness for duty (fatigue) decision aids developed an individual, mini-fatigue-assessment tool. It combines:

  • some rough rules-of-thumb on how much sleep you’ve had recently, and how long you’re likely to be awake
  • some simple fatigue questions
  • a sleepiness rating scale 

This tool can help you make better-informed decisions about whether you’re likely to be able to safely work your whole shift, and get safely back to where you’re sleeping afterwards.  

The tool recognises that everyone’s different and that many things affect fatigue (for example your sleep quality, general health and well-being, the nature of your tasks & working environment, and the time of day or night). A “safe” amount of sleep for one person may not be enough for someone else. It’s vital to raise any concerns you have, so if in doubt, put safety first - tell your supervisor immediately, and don’t put yourself or others at risk.

Good practice guidelines – fatigue factors

ORR’s guidance outlines a “triangulation” approach to assessing the likelihood of a worker suffering fatigue from a working pattern. The first step involves comparing the work pattern against good practice guidelines, to identify potentially fatiguing features.  Some good practice guidelines - fatigue factors – have been collated here, for use when

  • Assessing current work patterns and designing new working patterns;
  • Agreeing the rostering principles underlying work patterns;
  • Assessing proposed changes to work patterns (e.g. overtime, rest-day working, shift swaps);
  • Investigating incidents and fatigue concerns;
  • Developing key performance indicators (KPIs) for fatigue, to help identify likely fatigue hotspots and prioritise fatigue risk control efforts.

RSSB Project T1083 on bio-mathematical fatigue models

RSSB project comparing bio-mathematical fatigue models and providing guidance for the GB rail industry on their use.

The first stepin ORR's guidance involves comparing the working pattern against good practice guidelines - see the Fatigue Factors summary on our website.  The second step involves using a bio-mathematical fatigue model to assess the work pattern.

RSSB Project T1083 compared five available tools incorporating bio-mathematical models, and produced guidance on their use for the GB rail industry.  The booklet outlines what bio-mathematical fatigue models are, explains their potential role as part of a fatigue risk management system (FRMS), and provides advice to help organisations select a model which is appropriate to their needs.

Because many GB railway organisations use the Health & Safety Executive’s Fatigue & Risk Index (FRI), ORR has summarised some FRI-specific points from Project T1083 in “Points from RSSB Project T1083 regarding the Fatigue & Risk Index”.

CIRAS video on fatigue management for shift workers

CIRAS has produced this helpful 9-minute video to help staff understand the effects fatigue can have, and how fatigue risks can be reduced.

The video outlines some of the solutions CIRAS members have introduced that staff and management from other transport modes or organisations can consider adopting.

Fatigue Key Performance Indicators (KPIs) information sheet

ORR handout document suggesting some possible key performance indicators (KPIs) for staff fatigue.

Rail organisations, especially those carrying out safety critical work, should regularly measure the effectiveness of their fatigue prevention and control measures. The handout ORR produced following a workshop in April 2017 may useful to organisations devising or reviewing their own fatigue KPIs. It outlines a suggested approach for deriving fatigue KPIs, suggests some possible KPIs collated from railway and wider sectors, and provides links to further information.