Three track workers were put in danger after the wrong tunnel was closed despite multiple checks, the Rail Accident Investigation Branch (RAIB) said in its report on a near miss in Surrey last April.

At around 11:42 on 29 April 2025, a passenger train went through Bookham Tunnel on the approach to Bookham station while three track workers were walking through it.

The train was travelling at 33mph. The workers moved to refuges inside the tunnel or stood against the tunnel wall as it passed.

RAIB’s investigation found that a line blockage had been arranged for the wrong tunnel, nearby Mickleham Tunnel, not the tunnel the team was working in.

Neither the track workers nor the signaller who granted the line blockage had realised this.

The error in the safe work pack had been introduced during the planning stage for the work and went unnoticed, despite multiple checks.

RAIB identified two underlying factors.

The first was that Network Rail’s lack of a specific process for managing the transfer of information between its asset management systems and the system it uses for producing safe work packs allowed the introduction of the error.

The second was that steps in Network Rail’s process for producing safe work packs were either not routinely carried out or were not carried out effectively.

Recommendations

RAIB has made three recommendations to Network Rail:

• The first aims to reduce the risk of errors being introduced when using information from multiple systems to produce a safe work pack.
• The second aims for Network Rail to improve the implementation of its process covering work taking place on or near operational railway lines.
• The third recommends that Network Rail improve its assurance activities by better using the information provided by its safe system of work planning software.

RAIB also identified two learning points.

First, it reminded track workers and signallers who are undertaking safety-critical communications that clarity, effective listening, and reaching a clear and unambiguous understanding of what has been agreed is critical.

Second, staff who plan work on or near the line, and those who then deliver that work, should have a clear understanding of how all planned activities, including walking, will be undertaken.

‘Pattern of near misses will end in tragedy’

“The move away from unassisted lookout protection on the railway has made track work statistically safer, and that is welcome,” said Andrew Hall, chief inspector of rail accidents.

“However, our investigation into this near miss illustrates how safety is now heavily dependent on every worker having an accurate understanding of which lines are blocked, the timing of the block and where the safe working boundaries lie.

“Bookham Tunnel is one of a number of near misses that serve as a warning.

“Safety theory and bitter experience both tell us that a pattern of near misses will eventually end in tragedy, and that is what happened in Hertfordshire in March this year, where a track worker was struck and sadly lost their life.

“I know that work continues to try to reduce this risk further. Recent events show how urgent and important such work is.”