Severn Tunnel rail accident

The Severn Tunnel rail accident occurred in the tunnel on 7 December 1991.[1]

Severn Tunnel rail crash
Details
Date	7 December 1991
Location	Severn Tunnel
Country	United Kingdom
Line	South Wales Main Line
Operator	InterCity Regional Railways
Owner	British Rail
Cause	Axle counter failure or driver error
Statistics
Trains	2
Vehicles	InterCity 125 Class 155
Deaths	0
Injured	185 (5 serious)
List of UK rail accidents by year

The 08:30 London Paddington to Cardiff Central operated by an InterCity 125 was stopped at a signal guarding the entrance to the Severn Tunnel. On telephoning the signalman according to Rule 55, the driver was advised of a signal failure and given permission to proceed slowly at caution. Three miles into the tunnel, the train was struck from behind by a Class 155 Sprinter travelling from Portsmouth to Cardiff. 185 passengers were injured, including five seriously, but none fatally.[1]

Because track circuits were unreliable in the unusually wet tunnel environment (10 to 20 million gallons of water are pumped out per day),[2] axle counters were used instead. The official report into the accident[2] could not reach a firm conclusion, but speculated that the cause was either:

• an unaccountable error on the part of the Sprinter driver, or:
• technicians in the relay room at Severn Tunnel Junction had reset the axle counter while investigating the earlier fault, thus clearing the signal for the Sprinter.[1]

References

1. Stephen, Paul (7 December 2016). "Deep Impact". Rail. No. 815. Peterborough: Bauer Media. pp. 54–57. ISSN 0953-4563.
2. Seymour, R.J. Railway Accident in the Severn Tunnel. H.M. Railway Inspectorate.