A train was travelling at about 50mph when it struck the rear of a stationary Nottingham to London service in a collision that killed a driver and injured at least 160 people, an interim investigation report has revealed.
The Rail Accident Investigation Branch (RAIB) said the service from Corby had passed a red signal and continued accelerating before its driver applied the brakes around 10 seconds before impact.
Investigators have not yet established why the train passed the signal. Their investigation is continuing, and the report does not assign blame or liability.
The collision happened near Elstow, Bedfordshire, approximately 2.5 miles south of Bedford station, at around 5.13pm on Friday 19 June 2026.
The 4.40pm Corby to London St Pancras service struck the stationary 3.50pm Nottingham to London St Pancras train. Both were operated by East Midlands Railway.
The driver of the Corby service died. Investigators have so far identified 257 people aboard the two trains, including staff. At least 160 were injured and 102 were taken to hospital.
The Nottingham service had stopped unexpectedly after its Automatic Warning System, known as AWS, triggered an emergency brake application.
The system uses equipment on the track and train to alert drivers to signals ahead. A warning must be acknowledged promptly by pressing a button in the cab; otherwise, the emergency brakes apply automatically.
According to the report, the Nottingham train received an AWS warning while approaching signal WH154, even though the signal was showing green. A green signal should have produced a different sound which required no response from the driver.
The warning was not acknowledged within the permitted 2.7 seconds, and the emergency brakes applied. The train stopped at around 5.11pm, just over two minutes before the collision.
The Nottingham service was a five-car Class 810 train, part of the fleet whose introduction on EMR’s intercity routes began in December 2025. Its driver was already qualified and was undertaking additional training to drive Class 810 trains, accompanied by a driver-instructor.
Witness evidence indicated that neither recognised the alarm sounding from a loudspeaker above the driver’s head as an AWS warning. The report says the AWS acknowledgement button, which would have silenced it, was not pressed.
The driver contacted the signaller and reported an AWS fault. That call ended only seconds before the collision.
The report also describes differences between the Class 810’s enhanced safety-system control panel and the standard panel on trains with which the driver was more familiar. The investigation has not yet reached its final conclusions about the circumstances of the stop.
With the Nottingham train stationary ahead, signal WH154 was correctly displaying red to protect it from following trains.
The Corby service had previously passed a yellow signal, warning its driver to be prepared to stop at the next signal. Its onboard recorder showed that the driver acknowledged the AWS warnings for both that yellow signal and the subsequent red signal.
However, the train passed the red signal at approximately 58mph while accelerating, before reaching about 76mph.
The driver applied the full-service brake approximately 260 metres from the rear of the Nottingham train, followed around two seconds later by the emergency brake. Its speed had fallen to about 50mph when the trains collided.
Investigators said the curve of the track affected the view ahead. In the last available forward-facing CCTV footage, recorded about 600 metres from the stationary train, it was visible but the footage did not establish whether it was on the same track. A driver could experience the same limitation, the report said.
Signal WH154 was not fitted with track equipment for the Train Protection and Warning System, or TPWS, which can automatically apply a train’s brakes if it passes a red signal.
The report explains that the signal was exempt from the legal requirement for that equipment because the potential collision involved a train striking the rear of another travelling in the same direction on the same track. Network Rail can nevertheless fit the equipment where its assessment identifies sufficient risk.
A Network Rail assessment on 29 October 2025 placed the signal in a low-risk category for being passed at danger.
There had been no previously recorded instances of a train passing that signal at red since records began in 1985. However, investigators said trains were likely to encounter it at red very rarely. Analysis indicated that none had done so in 2026 before the accident.
There was also no alarm associated with the signal to alert the signaller if a train passed it at danger.
Initial testing after the collision found no faults with the signalling system. However, on 9 July, another Class 810 train approaching the same signal received an AWS warning even though it was showing green.
On that occasion, the driver acknowledged the warning within the required time, reported it and continued the journey.
Further investigation found that an electromagnet in the track equipment was positioned below the required height tolerance. Investigators are continuing to examine how that equipment interacted with the Nottingham train’s AWS system. They have found no evidence that the electromagnet was not correctly energised.
Both trains derailed in the collision, although their carriages remained broadly upright and in line. The two cabs at the point of impact became embedded together, and the trains moved approximately one carriage length before stopping.
Loss of onboard power prevented staff on both services from making railway emergency calls using their train radios. The Nottingham train’s driver and train manager placed emergency equipment on adjacent tracks to cause approaching signals to turn red.
A passenger reported the collision to the signaller using a signal-post telephone, followed shortly afterwards by the Nottingham train’s driver. Emergency services had also been alerted through a 999 call.
RAIB will continue examining the actions of those involved, why the Corby service passed the red signal, why the Nottingham train stopped, and the performance of braking and other safety systems.
The investigation will also consider the signal’s visibility, the assessment of risk at the location, how the trains withstood the collision and the emergency response.
A final report will be published when the investigation is complete. RAIB cautions that the interim findings may be refined or changed as further evidence is examined.
