The importance of allowing safety systems to function without interference “cannot be overstated”, according to the Rail Accident Investigation Branch’s final report into the “dangerous occurrence” at Wootton Bassett Junction (Wiltshire) on March 7 2015.
The incident under investigation involved steam locomotive 34067 Tangmere passing a signal at danger at Wootton Bassett Junction on the Great Western Main Line, and overrunning by 689 metres.
The West Coast Railways (WCR) charter straddled the junction around a minute after a First Great Western High Speed Train had passed through (RAIL 771-773). Tampering with safety systems, which rendered TPWS (Train Protection Warning System) brake demands ineffective, was identified as a cause of the incident.
Released today (May 5), RAIB’s investigation identifies a key learning point and five recommendations for improvements. A learning point is made separately to recommendations, to reinforce compliance with existing safety arrangements and the consequences of failing to comply.
In this case: “Allowing safety systems such as AWS (Automatic Warning System) and TPWS to function without improper interference is vital to the safe operation of the railway. The importance of this cannot be overstated. Bypassing safety systems, or isolating them other than in accordance with the requirements of the Rule Book, can have catastrophic consequences.
“The risks of running trains with safety systems such as AWS isolated have previously been highlighted by the inquiry into the 1997 accident at Southall, in which seven people were killed and a further 139 were injured.”
Recommendations include: the Rail Safety and Standards Board, steam operators and Network Rail should conduct a review into processes and procedures for overruns on the main line; WCR should make arrangements for an independent review of its safety culture; WCR should review arrangements by which drivers acquire and retain route knowledge; WCR should review arrangements for the fitting of On Train Data Recorders to its trains; NR should review how the design and implementation of emergency and temporary speed restrictions are managed by the Swindon Maintenance Delivery unit.
- For more on this story, see RAIL 801, on sale May 25.