An investigation found a “breakdown in communication” led to a rail worker being hospitalised after a collision on Kent’s high-speed network.

The crash happened on a section of the High Speed 1 (HS1) line, near Strood, and involved a multi-purpose vehicle (MPV) – used to clear and repair the tracks – and a stationary tamper, used for correcting the alignment.

The tamper was being prepared for coupling to a second MPV, which was standing directly next to it.

An operator was between the two as part of the preparation for the coupling.

The crash caused the two stationary vehicles to move along the track and strike the operator, who sustained injuries which required treatment in hospital.

Three of the staff onboard the vehicles were also knocked over by the impact but were not injured.

The MPV which initially collided with the tamper also sustained minor damage.

“Due to the design of the radio, neither the driver nor the machine controller were initially aware that communications had been lost...”

The Rail Accident Investigation Branch (RAIB) launched a probe into the collision which happened in the early hours of November 16, 2023.

It was normal practice for this coupling operation to be undertaken with another vehicle approaching the other end of the tamper, the government agency says.

“The established method of working was for the approaching vehicle to come to a stand at a ‘holding point’ situated about 50 to 100 metres away from the stationary vehicles,” the report states.

“The final movement would then be made at a very slow speed and under the control of the driver responsible for the coupling operation.”

But on this occasion, the second MPV did not stop at the holding point, according to the report.

This was because the driver reversing the second MPV did not have a view of the railway in the direction of travel of the vehicle.

And he was reliant on radio messages from a machine controller at the rear to know when to slow down or stop the vehicle.

“On the night of the accident, the radio being used by the machine controller had developed an intermittent fault, which led to a breakdown in communication with the driver,” the report added.

“Due to the design of the radio, neither the driver nor the machine controller were initially aware that communications had been lost.

“Although the machine controller subsequently realised the radio was not working and alerted the driver they needed to brake by a shouted warning, this occurred too late to avoid the collision.”

“Any injury on the railway is unacceptable, and we have already taken action both in response to the incident itself and to the findings of the RAIB report...”

RAIB discovered the type of radios being used during the movement did not transmit a constant “confidence tone” which would have alerted staff to the loss of communications.

It was also not normal practice for machine controllers to communicate constantly on long transit moves.

And it also found the type of MPVs used on HS1 were not fitted with any facility for machine controllers riding on the rear deck to brake the vehicle, despite an internal recommendation to fit this facility after a previous similar accident in 2021.

“An underlying factor in this accident was Network Rail High Speed (NRHS), the infrastructure manager for HS1, did not have safe systems of work for propelling moves or working on track when engineering vehicles were running during a possession,” the report states.

“A possible underlying factor was the strategic safety assurance undertaken by HS1 Ltd, which has the concession to operate HS1, which did not identify the recommendation to fit a braking facility to the rear deck had been closed with no actions being taken.”

Since the accident, NRHS has fitted its MPV fleet with emergency stop buttons next to the rear deck, secure communications systems and is due to install a rearwards-facing camera, connected to an in-cab monitor.

An NRHS spokesperson said: “The RAIB report into the collision between on-track machines on November 16, 2023, highlights important lessons and makes four recommendations Network Rail High Speed and HS1 Ltd are addressing.

“Any injury on the railway is unacceptable, and we have already taken action both in response to the incident itself and to the findings of the RAIB report.

“Since the incident, Network Rail High Speed has completed two key upgrades to its MPV fleet – installing emergency stop buttons adjacent to the rear deck and a secure communications system.

“We have also reviewed and updated key documentation, training and processes to drive further improvements in our safety arrangements.

“We are in regular communication with the Office of Rail and Road who will monitor our progress on implementing robust responses to these recommendations.

“Network Rail High Speed has engaged proactively with the RAIB during their investigation and drafting of their report, and we are committed to continuing to work with our industry partners to continuously improve safety on the railway.”