Abbots Ripton rail disaster
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The Abbots Ripton rail disaster occurred on the 21 January1876, when the Scotch express was involved in a double collision during a blizzard. Because many signals were frozen in the clear position, a coal train which ran ahead of the express could only be stopped by the Abbots Ripton signalman, who instructed the driver of the coal train to set back into the siding at the signal box. While the coal train was setting back, the express came up and crashed into the coal train, which had only partly cleared the line.
A second collision occurred shortly afterward when a northbound express crashed into the wreckage of the first collision. Since the driver of the northbound express was warned of the obstruction by the crew of the coal train engine, he tried to stop his train, but with the inefficient brakes then available he could not stop in time and crashed into the debris thrown about by the first collision.
At the time of the accident the block signals were normally left in the green position, and were only put to red while the block section was occupied by a train. A long gap between trains allowed the blizzard to freeze the signals in the green position, so that even when the signalman put the levers to red, the signals did not follow suit. It is also likely that there were no electric indicators repeating the actual position of the signals. Because the signal arms disappeared into a slot in the signal post, it was also easier for the arms to be frozen by the snow.
So a second train went through the false green signals and collided with the wreckage of the first smash.
[edit] Aftermath
Several things were changed as a result of this accident:
- the normal position of the block instruments and signals was made to be stop/red/closed.
- slotted signals were outlawed.
- electric repeaters of signals that were out of sight of the signalman were introduced.
- later the electric repeaters were interlocked with the block instruments as an extra precaution.
This accident is classified as a wrong side failure.
