Press Release from the UK Rail Accident Investigation Branch: Investigation into a dangerous occurrence involving an engineering train at Blatchbridge junction, near Frome in Somerset, 19 March 2012
At approximately 19:27 hrs on 19 March 2012 train 6Y33, comprised of specialised vehicles designed to relay track and hauled by a diesel locomotive, was approaching Blatchbridge Junction near Frome in Somerset.
Following a report by the driver of a train travelling in the opposite direction, train 6Y33 was stopped and the driver carried out an examination. He later reported to the signaller that the under-slung control cab of a track relaying vehicle within his train was detached and outside of the train’s normal gauge.
The control cab, although mechanically detached from train 6Y33, remained restrained by electrical cables and air hoses. It was later discovered that the detached cab structure had destroyed part of a footpath crossing on the approach to Blatchbridge Junction.
RAIB’s preliminary examination revealed that all of the eight bolts that secured the control cab to the track relaying vehicle had failed. It was found that the remaining parts of five of these bolts exhibited signs of fatigue failure. The three other bolts were missing.
The track renewal vehicles are owned by Network Rail and operated by Amey Colas. The vehicles were constructed by Matisa Ltd in Switzerland and are seven years old. Network Rail owns one similar set of vehicles and there are others in use worldwide.
The RAIB’s investigation will include an examination of the reasons for the failure of the bolts, the design of the control cab to vehicle body mounting arrangements, the design and vehicle acceptance processes, and the maintenance and inspection arrangements that were in place prior to the incident.
The RAIB’s investigation is independent of any investigation by the safety authority (the Office of Rail Regulation).
The RAIB will publish the findings of this investigation. This will be available on the RAIB website.