India train crash: a familiar chain of events
RSSB’s Greg Morse explores the similarities between the multi-train collision in India in 2023, which caused almost 300 casualties, and recent GB rail incidents.
On 2 June 2023, the Shalimar–Chennai Coromandel Express struck the rear of a freight train and derailed at Bahanagar Bazar, in the Indian state of Odisha. Another passenger train was struck by the debris as it passed.
The train had been travelling on the Up Main, just under linespeed at 80 mph. It should have continued on that line. But the route was switched to the loop where the freight was standing. In all, 294 people were killed and 1,175 were injured in the inevitable collision.
In scenes reminiscent of the 1952 Harrow and Wealdstone disaster, more than 15 fire rescue teams, 100 doctors, 200 police personnel, and 200 ambulances were mobilised. Local residents provided passengers with water and helped retrieve their luggage.
The trains involved were modern and the signalling system very similar to that used on GB rail. But there was something else that was familiar – the causal chain. In short, it was a wrongside failure. For the express, green light had followed green light. The last one should have been red to protect the freight.
The investigation found that the accident had been caused by a wiring error made by technicians working to provide new barriers at a level crossing in the area. Wiring modifications made on the day of the accident combined with wrongly recorded mods made in the same area several years before. As a result, the digital interlocking believed the points were set and locked for the mainline and set signal aspects accordingly.
Evidence from the dataloggers suggested that a points correspondence test had not been done after the work had been completed. This would have found the error.
The most famous incident on GB rail resulting from a wiring error occurred at Clapham in 1988. In this case, green light had also followed green light, when the last one should have been red to protect a train. Thirty-five people were killed in the resulting collision.
More recently, on 29 December 2016, a passenger train was routed to the wrong line at Cardiff East. Testing had failed to spot an issue with secured points. At Waterloo on 15 August 2017, a low-speed collision occurred because a wiring issue had not been found by testing. At Dalwhinnie on 10 April 2021, an empty train derailed on points whose wiring issues had not been picked up. At South Wingfield on 26 October 2022, a train was signalled into an occupied section. Again, the cause was a wiring issue. Again, testing failed to find it.
The Indian accident rightly gave a lot of people in our industry food for thought. We need to look beyond our own boundary fence to see safety from a different angle. The trouble is, RAIB’s investigations into Cardiff East, Waterloo, Dalwhinnie, and South Wingfield should have been doing that already.
We must learn from the Odisha accident, with the fundamental message of being compliant with tried and tested standards and having the processes to assure ourselves that all is in place and being followed. Testing must always be carried out in full, and work on the signalling system, and other assets, must always be done in accordance with standards.
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Image credits: BMphoto, Swattik Jana CC BY-SA 4.0 , via Wikimedia Commons
