Abbots Ripton rail accident

The Abbots Ripton rail disaster occurred on 21 January1876, when the Flying Scotsman express train from Edinburgh to London was involved in a double collision during a blizzard, [Report of the Court of Enquiry into the Circumstances Attending the Double Collision on the Great Northern Railway which occurred at Abbots Ripton on the 1st January 1876, Board of Trade, 23rd February 1876] with a coal train and another passenger train.

Overview

A coal train preceding the Flying Scotsman was stopped by the Abbots Ripton signalman, to be shunted back into a siding. Signals which should have been at "danger" to protect the coal train were frozen in the "clear" position, and the express approached at full speed and crashed into the coal train, which had not fully cleared the main line. The wreckage obstructed the down (northbound) line and a second collision occurred some minutes later when a northbound express to Leeds crashed into the wreckage.

Thirteen passengers lost their lives in the collisions, and 53 passengers and 6 traincrew members were injured.

Sequence of events

On the afternoon of 21 January1876 an exceptional snowfall started and continued for some hours, resulting in very difficult conditions. Some telegraph wires were brought down and railway signals in several places were frozen in the "clear" position. The southbound coal train was supposed to have been recessed at Holme to let the Flying Scotsman overtake, but the signals there were improperly showing "Clear" and the coal train continued its journey.

It was stopped at Abbots Ripton (where it was ordinarily scheduled to recess) and had started to set back into the refuge siding there. At 6:44 p.m. the Flying Scotsman crashed into it at full speed, with the steam still on. The Abbots Ripton signalman had put the signal levers to the "danger" position to protect the coal train, and had not given the "Line clear" telegraph signal to the preceding signal box, Wood Walton, but the signals at both places were showing "clear", luring the express to destruction.

The signalman was evidently dazed by the events, but after a delay he tried to give an "obstruction" signal by telegraph to Huntingdon signalbox to the south, but the signalman there refused to take the signal seriously, and a northbound express train, bound for Leeds, was allowed to approach. A platelayer at Abbots Ripton ran forward (southward) and placed two detonators on the down (northbound) line to warn the approaching Leeds train. When the Leeds train ran over the detonators its driver applied the brakes, but his train did not stop in time, and it ran into the wreckage at some speed.

Immediate causes

The immediate cause was the freezing of several sets of signals in a false "clear" position. The pattern of signals in use are described as "slotted post" signals, in which the blade of the signal -- the signal arm -- is hinged in a slot within the thickness of the timber signal post. Operating practice at that time was that the signals were left in the "clear" position continuously unless it was required to protect a static obstruction. Consequently the signals stood at clear for considerable periods of time.

The coal train had already run past all the signals at Holme from this cause, as the signalman there had wanted to recess the train there. The Holme signalman informed his station master, but the latter took no action, despite the obvious risk of disaster.

The Flying Scotsman train ran past false "clear" signals at Wood Walton (immediately north of Abbots Ripton) and the distant and home signals at Abbots Ripton itself.

After the collision had taken place, the Abbots Ripton signalman was unable to alert the signalman at the main signalbox at Huntingdon, some distance to the south, because that man refused to acknowledge and read the telegraph signal. The Abbots Ripton signalman later sent an "obstruction" signal to Stukeley, the signalbox immediately to the south at 6:52 p.m., but this was just at the moment when the northbound Leeds train was passing at full speed under clear signals.

The foreman platelayer at Abbots Ripton had placed two detonators on the line convert|1136|yd|m from Abbots Ripton signalbox and rather more from the point of collision (and further than the Abbots Ripton distant signal). However the driver of the Leeds train was unable to stop in time and ran into the wreckage at a speed estimated by him to be convert|20|mph|km/h and by other witnesses to be very much greater.

Recommendations

The Board of Trade enquiry report made numerous recommendations; in contrast to present-day reports, the recommendations were general and persuasive, rather than specific and mandatory. The most important are:

* Improving signals so that they work properly in frost and snow, and that they provide an indication to the signalman if they are not operating properly
* Keeping the signals normally at danger, so that if they stick there is unlikely to be a false "clear"
* The use by signalmen of hand lamps in bad weather to confirm the indications of fixed signals
* The provision of telegraph apparatus in all signal boxes
* The improvement of braking systems on trains
* The suspension of less important trains, and the reduction in speed of other trains, in very severe weather conditions.

Fundamental causes

The Board of Trade enquiry report has to be read in the context of attitudes of those days, and the reporting officer was not empowered to order widespread improvement works on the railways.

There are a number of fundamental issues which a modern investigation would explore further. The first is the widespread failure, at "clear" of all the signals at Holme, Wood Walton, Abbots Ripton (and also Huntingdon South). The weather was exceptional but it seems improbable that so many signals should stick simultaneously, unless at least some of this phenomenon had taken place before. If that is so, it is a serious managerial failure that no prior corrective action had been taken. The Holme station master seems not to have thought that the coal train improperly running past his station was a very exceptional event.

In the event of visibility being reduced by fog or falling snow, platelayers were required to be posted at the important signals, to place detonators on the line when signals are showing "caution" or "danger", in case a driver failed to see the signal. At Abbots Ripton, the platelayers had not yet arrived at their posts, but there was no requirement to apply special precautions in case of drivers being unable to see the signals. (This would not, of course, have prevented the collision at Abbots Ripton, because the signals were showing false "clear" indications.) There was a general instruction to drivers to run at reduced speed if necessary in extreme weather conditions, but it is easy to read between the lines, that to act on this was dishonourable, and none of the drivers involved considered doing so.

The foreman platelayer at Abbots Ripton had run southward and placed two detonators on the line beyond the distant signal -- that is, a greater distance away from the obstruction than the signal itself provided (convert|1136|yd|m from the signalbox). The Leeds train driver heard the detonators explode and realised their meaning, but still ran into the wreckage at some considerable speed. This suggests that in the ordinary course of working, the location of the distant signal was inadequate for a driver to stop in the distance from there to the home signal (or other obstruction).

The signals had stuck in the clear position, and this is usually inferred to mean that the signal blade had frozen within the slotted post. However the Board of Trade report makes several references to snow and ice blocking the free operation of the operating wires and pulleys. In developing his recommendations he explores the possibility of covering the wires, or providing rods, or two wires in a loop, to prevent a recurrence. Contrary to general belief, he did not specifically recommend that the slotted post signals should be eliminated.

This accident is classified as a wrong side failure. Improved signals occurred after the accident. [ [http://mikes.railhistory.railfan.net/r101.html Railhistory Railfan: "Imporved Signals after the 1876 Accident"] ] [ [http://www.signalbox.org/signals/gn.htm Signal type of accident] ]

References

* [http://www.railwaysarchive.co.uk/documents/BoT_AbbottsRipton1876.pdf Board of Trade Report file (PDF)]

External links

* Photos: [http://www.old-print.com/cgi-bin/category.cgi?item=N1400876282 OldPrints: "Abbotts Ripton Wreckage"]
* Signal types: [http://mikes.railhistory.railfan.net/r101.html Railhistory Railfan - Signals]
* [http://library.kent.ac.uk/library/special/html/specoll/CB-DIONW.HTM University of Kent Library, UK: "Dion William Boucicault (1855-1876) and the Abbots Ripton Railway Disaster"]