A train travelling at over 100mph nearly hit a track works in Hertfordshire last month.

A Rail Accident Investigation Branch (RAIB) notice said the East Midlands Railway train was travelling at 104mph at 9.53 am on 23 April when it nearly hit a worker on the down fast line about 2.7 miles north of Harpenden station.

The track worker was crossing an underbridge when the train approached.

This bridge did not have the required clearance between the bridge parapet and the nearest running rail for the track worker to be far enough away from the train, so that they were in a position of safety. 

Upon seeing the track worker on the bridge, the driver sounded the train's horn and then slammed on the breaks.

The track worker reached the far side of the bridge just before the train passed them.

Once the train stopped, the driver reported the incident to the signaller as they were unsure if their train had struck the track worker.

The track worker was a member of a group that was working to the north of the bridge.

They had earlier left the group and walked alone back to their van at the track access point, which was just to the south of the bridge.

At the time of the near miss, they were walking alone back towards the group.

An RAIB investigation will now take place and consider:

• The actions of those involved and the factors that may have influenced them
• What rules and processes applied to the track workers, both as a group and as individuals, when crossing a structure with limited clearance
• The way in which the work was planned and how the risks associated with being on or near a railway line were being managed
• Any underlying management factors.

"Our investigation is independent of any investigation by the railway industry or by the industry's regulator, the Office of Rail and Road," the statement said.

"We will publish our findings, including any recommendations to improve safety, at the conclusion of our investigation. This report will be available on our website."