A planning error in a safe work pack led to a passenger train passing dangerously close to three track workers inside Bookham Tunnel, rail investigators said.
The Rail Accident Investigation Branch said the near miss happened at about 11:42 a.m. on April 29, 2025, as a passenger train approached Bookham station in Surrey. The train was traveling at 33 mph when it passed the workers.
The workers either moved into refuges inside the tunnel or stood against the tunnel wall as the train passed, RAIB said.
Investigators found the track workers were walking in a different location from the one that had been blocked to trains. Neither the workers nor the signaler who granted the line blockage realized the mistake.
RAIB said the safe work pack, which formally detailed the safety arrangements for the work, incorrectly included line-blocking arrangements for the nearby Mickleham Tunnel rather than for the tunnel where the team was working. The error was introduced during the planning stage and went unnoticed despite the pack being checked multiple times.
Investigators identified two underlying factors: Network Rail lacked a specific process for transferring information between its asset management systems and the software used to produce safe work packs, and steps in the process for producing those packs were either not routinely carried out or not carried out effectively.
RAIB made three recommendations to Network Rail. They call for reducing the risk of errors when using information from multiple systems, improving the implementation of processes for work on or near operational railway lines and making better use of safe system of work planning software in assurance activities.
The agency also issued two learning points, emphasizing the need for clear, safety-critical communication between track workers and signalers and for workers and planners to share a common understanding of how walking and working activities will be carried out.
Andrew Hall, chief inspector of rail accidents, said the move away from unassisted lookout protection has made track work statistically safer, but the Bookham Tunnel near miss shows railway safety now depends heavily on workers having an accurate understanding of which lines are blocked, when those blocks apply and where safe working boundaries are located.
Hall said a pattern of near misses can eventually end in tragedy, pointing to a March incident in Hertfordshire in which a track worker was struck and killed.
