The Rail Accident Investigation Branch (RAIB) has released its report on a track worker fatality at Ruscombe Junction, near Reading on 29 April 2007.
The full report into the incident is available here:

A summary of the accident is: On Sunday, 29 April 2007 at 11.26am, an empty stock train, 5Z71, was travelling from Old Oak Common depot to Reading depot when it struck and fatally injured a track welder at Ruscombe Junction. The accident occurred as the train passed a high-speed crossover where the welder was carrying out repair work. The two other on-site workers were unharmed and the train did not sustain any damage.

The immediate cause of the accident was that the welding team did not move to a position of safety as train 5Z71 approached, which resulted in the welder being hit by the train. There were two contributory factors which involved the decision-making of the on-site team and the train driver's actions as he approached the track workers. The investigation also identified that an air ambulance helicopter landed on the railway lines without the proper authority.