Alice Monk
Principal Human Factors Specialist, RSSB
Approximately 300 trains each year pass stop signals without authority on the GB mainline. These events are known as signals passed at danger (SPADs). SPADs rarely lead to serious incidents, but when they do the consequences can be severe.
Since 2021, rail operators have been recording detailed information about the causes of SPADs into a national reporting system called Safe Insights. These reports capture 10 system-level causes of SPADs. These are the job and organisational contributors to the event, also known as the 10 incident factors. They also record the actions of the individuals involved. Fatigue, health, and wellbeing (FH&W) is the second most common system-level cause of SPADs.
Overall, 29% of the 689 recorded events included at least one cause related to FH&W. These factors are known to slow reactions, reduce attention, and impair decision making, reinforcing the message that FH&W should be a central part of managing SPAD risk. So, let’s break it down further.
Under the bonnet on fatigue, health, and wellbeing
Within the Safe Insights FH&W category, users also enter a relevant subcategory and additional detail in a free-text field. This allows for more granular insight into underlying causes.
In the physical, mental, or emotional health subcategory, issues relating to mental and emotional health are the most common. They account for almost three-quarters of the causes in this subcategory.
Activating AI
Analysis of free-text fields can be challenging with large data sets. However, AI can support this process by identifying key themes within unstructured data. For this analysis, we used Copilot, Microsoft’s AI tool, to extract and group themes from the dataset. The key themes are presented below, ordered by frequency.
A notable finding was the prevalence of non-disclosure. There were multiple entries where mental or emotional health issues had not been disclosed to management before the SPAD.
Enabling more powerful interventions
Emotional and mental wellbeing challenges are often chronic, cumulative, and under-recognised, yet they have a direct impact on operational performance. This analysis highlights a clear opportunity to identify and implement mitigations that prevent SPADs by better supporting operational staff.
Practical actions could include embedding wellbeing prompts into pre-duty conversations, strengthening reporting pathways, and improving the culture in investigations. There is also scope to provide more proactive support for staff experiencing stress, fatigue, or grief.
Ultimately, this work supports a shift beyond individual actions towards a deeper understanding of system-level contributors. Collecting and analysing this data at a national level provides the insight and evidence to drive system-wide improvements, addressing system weaknesses to prevent future SPADs.