The Rail Accident Investigation Branch (RAIB) has launched a preliminary examination into an accident in which a track worker was struck by a road-rail vehicle (RRV).
The incident happened on the Midland Main Line at Braybrooke, Northamptonshire.
The operative was walking along the track and directing the movement of another RRV on an adjacent line when they were struck.
The track worker sustained a leg injury that required hospital treatment.
The railway watchdog says it has published a safety digest with the information gathered to date.