RAIB also found the rule book did not cover the specific circumstances of the “wrong-direction” movement in the incident, meaning that the signallers had been ignoring the rules unintentionally.
It asked the RSSB to consider if the modules in the rule book should account for such scenarios.
Investigators also found the incident highlighted how staff should have a better understanding of how their personal issues could have an impact on their work.
They learnt the signalling shift manager had been dealing with “significant personal issues” that had been affecting their concentration.
After reviewing the witness evidence, the RAIB said that if this member of staff had declared these issues to their manager they would have been taken off duty on compassionate grounds.
The RAIB suggested staff should “ask a competent person” and challenge colleagues if they were unsure about work being done.
Responding to the report, a Network Rail spokesperson said it had taken the recommendations “very seriously”.
They said Network Rail was implementing the recommendations, including changes in training for signallers.
