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Derailment near Knaresborough - RAIB investigation

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Derailment near Knaresborough - RAIB investigation

Unread postby John Webb » Fri Nov 20, 2015 2:41 pm

The RAIB has announced (https://www.gov.uk/government/news/derailment-near-knaresborough) that it is investigating this recent derailment.
At 07:22 hrs on 7 November 2015, the 06:52 hrs Northern Rail passenger service from York to Harrogate derailed on points 3A between Cattal and Knaresborough stations. The train (reporting number 2C07) consisted of two Class 150, 2-car multiple units.

At this location the single line section of track changes to double track (a crossover). The intention was for the train to remain on the down main line and not to use the crossover.
Train movements at this location are controlled from Knaresborough signal box, using a lever frame and relying on a mix of mechanical and electrical interlocking. The line speed in this area is 65 mph (104 km/h) but the train was travelling at 19 mph (30 km/h) at the time of the derailment, having been authorised to pass signal K10 at danger (red). Signal K10 protects the crossover.

The leading 5 bogies derailed and damage was sustained by both the train and track. None of the train crew or five passengers on board were injured. The line was re-opened at 12:58 hrs on 8 November 2015.

Train 2C07 was authorised past signal K10 at danger by the signaller in Knaresborough signal box after the signaller experienced difficulties clearing the signal. These difficulties were almost certainly associated with the points 3A not being in a safe condition for the train to pass.

The signaller was appointed to work Knaresborough signal box the afternoon before the derailment as the resident signaller was sick. He had not operated the signal box for a number of months.
Last edited by John Webb on Thu Aug 4, 2016 1:47 pm, edited 1 time in total.
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Re: Derailment near Knaresborough - RAIB investigating

Unread postby Pete2320 » Fri Nov 20, 2015 2:55 pm

I think we must not pre judge this but
The signaller was appointed to work Knaresborough signal box the afternoon before the derailment as the resident signaller was sick. He had not operated the signal box for a number of months.
somehow reads peculiar. I wonder what it actually means? Probably nothing more than a relief man being asked to work the box, ie nothing unusual.

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Re: Derailment near Knaresborough - RAIB investigating

Unread postby Stuart Johnson » Fri Nov 20, 2015 7:11 pm

Pete2320 wrote:Probably nothing more than a relief man being asked to work the box, ie nothing unusual.

If only it were that simple, but it wasn't. All will be revealed in due course, and further speculation is not likely to be helpful.
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Re: Derailment near Knaresborough - RAIB investigating

Unread postby John Webb » Thu Aug 4, 2016 1:42 pm

RAIB Report published today (4th Aug '16) - see https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/543630/R162016_160804_Knaresborough.pdf
Summary:
At 07:22 hrs on 7 November 2015, a Northern Rail passenger service from York to Harrogate derailed on a set of points on the approach to Knaresborough station. The train consisted of two class 150, 2-car multiple units.

The leading five bogies derailed and damage was sustained by both the train and track. None of the train crew or five passengers on board were injured. The line was re-opened at 12:58 hrs on 8 November 2015.

The signaller in Knaresborough signal box had authorised the train to pass a signal at danger (red), without realising that the set of points beyond the signal was in an unsafe condition. The signaller had not checked the associated points position indicator in the signal box and misinterpreted the significance of being able to reverse the signal lever, leading him to believe that the route was correctly set and safe.

The signaller that day was a mobile operations manager. As a mobile operations manager, his core work was to respond to faults and incidents on the railway network; he operated signal boxes infrequently.

The RAIB concluded that the signaller did not have a full understanding of the working of Knaresborough signal box and that this lack of knowledge may have been the result of either poor initial training or the way his knowledge had been maintained.

An underlying factor to this incident was the lack of robustness of Network Rail’s competence management system for non-signallers (the people within Network Rail whose core duty is not to operate signal boxes but who occasionally have to do so).

In March 2016, Network Rail re-issued the operations manual for the staff in charge of operating signalling equipment. In April 2016, Network Rail started an end-to-end review of the way it manages the competence of its signallers.

Recommendations
As a result of this investigation, RAIB has made one recommendation on Network Rail to review whether the changes that it has recently made to the operations manual have resulted in non-signallers maintaining the required level of knowledge and experience.

RAIB has identified five learning points. The first three learning points relate to the actions of signallers in degraded operating conditions. The fourth learning point relates to the importance of investigating and understanding the underlying reasons for repeated asset failures. The final learning point relates to the actions of drivers when authorised to pass a signal at danger and after an incident.
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Re: Derailment near Knaresborough - RAIB investigation

Unread postby Graham Maxtone » Fri Aug 5, 2016 1:20 pm

A two step lever in the 'box would have prevented the basic misconception. I thought they were standard on mechanical frames working motorised points? The lever would not go fully over in the frame until the points had moved to the called position.
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Re: Derailment near Knaresborough - RAIB investigation

Unread postby Danny252 » Fri Aug 5, 2016 1:48 pm

Comments elsewhere imply that a motor point lever not having any intermediate lock is not unusual for "eastern region boxes", and paragraph 74 in the report states that there is no requirement for such locks.
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Re: Derailment near Knaresborough - RAIB investigation

Unread postby John Hinson » Fri Aug 5, 2016 2:06 pm

The Southern likewise.

Intermediate locks can be a hindrance where there is a mixture of motor points and mechanical - in a nutshell if the mechanical ones are released in the interlocking by the motor ones, you cannot set the road during a failure, even if the motor points have been clipped up.

In all honesty, the position of a lever should not distract from the need to check indications. Think of a situation where the detection is lost after a lever has been operated . . .

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Re: Derailment near Knaresborough - RAIB investigation

Unread postby Graham Maxtone » Fri Aug 5, 2016 2:18 pm

Yes indeed. I did wonder if the chap on duty had worked both types..
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Re: Derailment near Knaresborough - RAIB investigation

Unread postby Stuart Johnson » Fri Aug 5, 2016 8:17 pm

As the report says, the only other boxes he had worked had mechanical points, and he seems to have assumed from his experience with them that if he could get the signal lever over, he had detection.
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Re: Derailment near Knaresborough - RAIB investigation

Unread postby Mike Hodgson » Sun Aug 7, 2016 9:42 am

Stuart Johnson wrote:As the report says, the only other boxes he had worked had mechanical points, and he seems to have assumed from his experience with them that if he could get the signal lever over, he had detection.


If he did make that assumption, might the regular man not have made the same mistake?
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Re: Derailment near Knaresborough - RAIB investigation

Unread postby StevieG » Sun Aug 7, 2016 10:53 am

Mike Hodgson wrote:
Stuart Johnson wrote:As the report says, the only other boxes he had worked had mechanical points, and he seems to have assumed from his experience with them that if he could get the signal lever over, he had detection.


If he did make that assumption, might the regular man not have made the same mistake?
Possible Mike, but we'd hope not if he had been properly trained up on power points for his own Box.

But even with points, detectors, and signals that are all purely mechanical, if getting a signal lever fully reversed for a signal that reads through points that are facing for the move, fails to budge the signal from being 'On', it's still not right to think that the points are properly set. [Okay, providing that all the equipment is correctly adjusted and in good order, that scenario is only more likely the further away from the box that the points are located : The nearer they are, the more unusually difficult it is to get a signal lever fully Reversed if the detector hasn't cleared because you're just stretching the wire between the box and the detector (and if they really are quite near, it's likely to be impossible to pull the signal lever more than part-way over), but IMHO the principle is the same : absence of a points repeater indication, if provided, or if not, the signal not clearing, is the key warning that all may not be well with points.]
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