The Rail Accident Investigation Branch published a report on 8 October 2026 into an unsafe movement of locomotives being coupled at the Bluebell Railway in East Sussex on 9 August 2025. According to the report, at around 15:00 that Saturday a shunter was coupling two steam locomotives, Fenchurch and Stepney, when they unexpectedly moved while the shunter was between them. The locomotives moved around 3 metres (10 feet) before another member of staff on the platform stopped the movement. The shunter was uninjured but shaken. The coupling was taking place during the railway's 65th anniversary mini-gala, in preparation for the locomotives' return to a nearby shed.

The report attributed the movement to steam pressure building up in Fenchurch's cylinders because the regulator valve was not fully closed, admitting steam. The reverser was not in a position that would have reduced the risk of movement, and the locomotive had not been effectively immobilised because its air brake was not fully applied. The shunter's actions to prevent movement were ineffective because they had not been made aware of the braking system type. The report identified as an underlying factor that the Bluebell Railway was not effectively managing risks associated with coupling air-braked rolling stock.

RAIB made one recommendation to the Bluebell Railway, calling for a risk-based review of its arrangements for coupling and uncoupling rail vehicles. The branch noted that its investigations aim to prevent future accidents and do not establish blame or liability.