The Office of Rail and Road (ORR) today reports in its interim review that Hitachi’s Class 800 and 385 series trains were affected by stress corrosion and fatigue cracks, resulting in a significant number of Class 800 trains being withdrawn from service in May. The trains have since performed as specified, largely due to a swift and collaborative response by industry. However, the report demonstrates the importance of understanding and predicting failure modes and the continued need for high-level strategic direction to guide advanced materials research, development and innovation. You can read more about this in the recent Royce landscaping exercise which examined the impact of degradation on key infrastructure, and set out key recommendations.
The regulator commended the rapid industry response and subsequent work to safely reintroduce trains to service. Stress corrosion cracking occurs when susceptible materials are exposed to a specific corrosive substance while subject to stress.
ORR’s report found that once the cracks were identified, the industry worked collaboratively to swiftly withdraw the trains and then to establish a suitable process for assessing which trains were able to return to service.
The regulator’s interim report finds that since being put back into service, trains have performed as specified, with no unsafe conditions or harm arising from the cracking.
ORR continues to work with Hitachi and the industry and expects to publish a final report in December 2021.
HM Chief Inspector of Railways at ORR Ian Prosser CBE said:
“Our interim findings confirm the cracking in the yaw damper and lifting plate are a result of fatigue and stress corrosion cracking – and that Hitachi made the sensible decision to withdraw all trains.
Since then, the majority of trains have been put back into service with no unsafe conditions and no harm arising from the cracking.
I welcome the good collaboration that has taken place since this issue arose. We are continuing to work with all parties to determine the root cause and will publish our final report in December.”
ORR’s final report will establish the root cause of the cracking and will review Hitachi’s plan for long term fleet recovery and management and identify any areas for improvement for the industry.