At around 08:25 on 25 February 2025, train reporting number 1A12, the 0700 Hull to London Kings Cross service, operated by LNER, was involved in an overspeeding incident at Grantham South Junction.

The train departed after a planned stop at Grantham station with the signal indicating that the train was to diverge from the main line onto a parallel slow line at Grantham South Junction. This divergence has a permanent speed restriction of 25 mph (40 km/h). However, train 1A12 was travelling at around 55 mph (87 km/h) when it traversed the junction. Staff on board reported receiving minor injuries due to the overspeed, although there were no reported passenger injuries. The permissible speed in this area for a train which remains on the main line is 115 mph (184 km/h).

RAIB was notified of the incident soon after it occurred. We have since gathered evidence from the railway industry and carried out a preliminary examination into the circumstances surrounding the incident.

Our preliminary examination found that there is a strong likelihood that factors were present in this incident that were similar to those identified during RAIB’s investigations into a train overspeeding at Spital Junction, Peterborough, 17 April 2022, (report 06/2023) and a similar event at the same location on 4 May 2023 (report 10/2024).  Some of the recommendations from these investigations remain open and we have concluded it is unlikely that further investigation will lead to new recommendations for the improvement of railway safety. Consequently, RAIB will not investigate further or produce an investigation report.

However, this incident again illustrates the issues associated with relying completely on train drivers reacting appropriately to a junction or route indicator to control the risks presented by trains taking diverging low-speed turnouts on high-speed through routes. This risk may be increased by the introduction of higher performing train fleets, and possibly by routing patterns on an ever busier railway.

RAIB has written to the Office of Rail and Road, to draw its attention to this incident when considering industry responses to the recommendations made in the Spital Junction reports and the wider questions within the industry around protection against overspeeding.

We have copied the letter to Network Rail, LNER and the Rail Safety and Standards Board so that they are aware of the contents.