The much-delayed and consulted upon final report on this accident has finally been published. Obviously there is not much new in it, as what happened and broadly why are already known. I think that the final points are about what ought to have been done, and what should and can be done in the future, to reduce the probability of such events.
The final report is
on this page, and this is the key section of the summary in it:
The causes of the accident were that wheel/rail adhesion was very low in the area where the driver of train 1L53 applied the train’s brakes, that the driver did not apply the train’s brakes sufficiently early on approach to the signal protecting the junction to avoid running on to it, given the prevailing low level of adhesion, and that the braking systems of train 1L53 were unable to mitigate this very low adhesion.
The level of wheel/rail adhesion was very low due to leaf contamination on the railhead, and had been made worse by a band of drizzle that occurred immediately before the passage of train 1L53. This leaf contamination resulted from the weather conditions on the day of the accident, coupled with an increased density of vegetation in the area which had not been effectively managed by Network Rail’s Wessex route.
Network Rail’s Wessex route had also not effectively managed the contamination on the railhead with either proactive or reactive measures. RAIB▸ ’s investigation found that a probable underlying factor was that Network Rail’s Wessex route did not effectively manage the risks of low adhesion associated with the leaf fall season. RAIB also found that South Western Railway not effectively preparing its drivers for assessing and reporting low adhesion conditions was a possible underlying factor.
RAIB has also made two safety observations. These relate to the application of revised design criteria for the Train Protection and Warning System and the assessment of signal overrun risk and how this accounts for high risk of low adhesion sites. Two issues were found relating to the severity of the consequences. These were a loss of survival space in the driver’s cab of train 1L53, and the jamming of internal sliding doors, which obstructed passenger evacuation routes.
Since the accident, Network Rail has reviewed its training and competence framework for off track staff at network level, and is also reviewing its adhesion management standards. Network Rail’s Wessex route is reviewing its arrangements for proactively responding to reports of low adhesion, including how it undertakes railhead treatment.
South Western Railway has made changes relating to training and briefing of its drivers to ensure information on autumn arrangements has been effectively briefed and understood.
[continues with more changes of this kind]
