Safe railways for Australia

Safety Bulletin: ATSB investigation report findings on use of bio-mathematical models of human fatigue – learnings for the rail industry

15 December 2017

The Australian Transport Safety Bureau (ATSB) recently issued a report of a reopened investigation into the ditching of an Aeromedical ambulance off Norfolk Island that provides findings relevant to the rail industry. They include:

The operator’s application of its fatigue risk management system overemphasised the importance of scores obtained from a bio-mathematical model of fatigue (BMMF), and it did not have the appropriate expertise to understand the limitations and assumptions associated with the model. Overall, the operator did not have sufficient risk controls in addition to the BMMF to manage the duration and diming of duty, rest and standby periods.

The report identified a limitation of use of the bio-mathematical model FAID in relation to roster patterns involving minimal duty time or work in the previous 7 days. ATSB noted that:

…if there has been very little duty time in the previous seven days FAID will underestimate the potential fatigue level associated with the next duty period, and at times, this level of underestimation can be significant.

Rail Safety National Law requires rail transport operators (RTOs) to take into account and assess a range of fatigue factors relevant to the particular context of the rail safety work. Bio-mathematical models can be a useful tool in assisting RTOs to evaluate work schedules but cannot be relied upon as the sole method of identifying and managing fatigue risk factors. ONRSR recommends that RTOs review the ATSB report findings in light of the particular properties of the bio-mathematical model software they are using.

A range of fatigue management resources are available on the ONRSR website. For further information contact ONRSR on 08 8406 1500.