**Clayton tunnel kollision** [[25. august]] [[1861]]

But in many cases, and on many lines of railway...the exigencies of the traffic prevent the [time] intervals from being strictly kept, and they become habitually disregarded. The trains run at various speeds, from 10 miles an hour or less, in the case of a heavy mineral train, to 60 miles an hour or more, in that of an express passenger train; and such intervals become useless, while much longer intervals are in themselves insufficient...
I need not here quote the long catalogue of collisions that have occurred from time to time in the attempt, almost universally made in the first instance, to secure safety by means of an interval of time interposed between trains..."


Train Operator(s) 
London, Brighton & South Coast Railway 
Primary Cause(s) 
Signaller error 

Secondary Cause(s) 
Inadequate signalling layout, excessive working hours, inadequate time interval 

Result
Rear collision, derailment

No. Fatalities
23 

No. Injured
176 

[[http://www.railwaysarchive.co.uk/eventsummary.php?eventID=24|The report into the collision between two trains in Clayton tunnel, caused by an insufficient time interval and a misunderstanding between two signallers]]