The Rail Accident Investigation Branch (RAIB) has issued a Safety Digest following an investigation into an overspeeding incident at Grantham South Junction in Lincolnshire on 26th September 2025.

The incident occurred when a London North Eastern Railway (LNER) train from Middlesbrough to London King’s Cross passed through a set of points at a speed of 56 mph, which is above the maximum permitted speed of 25 mph.

After the train had passed Grantham station, it was booked to run on the Up Fast line, but instead was signalled onto the Up Slow line at Grantham South Junction to allow another service to pass.

The driver was advised that their train was being diverted at the junction by an illuminated junction indicator. The signal associated with the indicator was set to remain at red (danger) until the approaching train was close enough for the junction indicator to be legible. When the diverging route is set, the signal will only clear from red to yellow (caution).

CCTV image from the train shows the signal displaying a yellow aspect and a diverging route indication. The driver initially kept the train below 30 mph until around 350 metres past the signal, when they began to apply traction power to increase train speed as it approached the junction. As the junction points diverted the train towards the Up Slow line, it lurched, causing some standing passengers to be thrown to the floor, and luggage to fall from overhead racks.

After initially shutting off traction power, after around 4 seconds, the driver reapplied power and continued the journey to London, but did not report the incident. As a result of the train lurching, some passengers raised their concerns on social media, and when the train manager became aware that a falling suitcase had injured a passenger, they checked on the passenger’s condition and reported the injury to LNER control.

LNER control staff only received a limited description of the incident from the train manager when questioned about the incident. The full seriousness of the incident was not revealed until November 2025 during an internal investigation by LNER, when internal CCTV from the train and data from an on-train data recorder were reviewed. The incident was then reported to RAIB and Network Rail.

During their investigation, LNER reviewed CCTV images from the train and internal CCTV, which showed the train manager entering the driving cab around 9 minutes before the incident and leaving about 3 minutes later. Although train managers are permitted to enter the driving cab if required by their duties, this must be kept to a minimum to avoid unnecessary distraction of the driver.

In their initial response, neither the driver nor the train manager stated that the train manager was in the driving cab at the time of the incident. RAIB has concluded that the train manager’s prolonged presence in the cab possibly distracted the driver. Coupled with the train being diverted from its previously booked route, that may have contributed either to the driver not observing the route information provided by the junction signal, or they forgot this information after passing the signal.

Important safety messages arising from RAIB’s investigation show:

• Infrastructure managers should identify all potential risks at a location after assessing the effectiveness of risk mitigation at similar locations.
• Train crew should follow operating rules regarding access to driving cabs, and be aware that unauthorised or unnecessary access may risk distracting drivers.
• Train crew must report operational incidents promptly so that trains and infrastructure involved can be inspected and any necessary investigations started.

Other recent overspeeding incidents investigated by the RAIB include a further incident at Grantham South Junction in February 2025, and at Hitchin in Hertfordshire last December