Great Western Coffee Shop

Gloucestershire to Wales line closed after derailment

(http://news.bbcimg.co.uk/media/images/70512000/jpg/_70512862_70512858.jpg)
The train derailed while travelling close to London Road in Gloucester

A railway line between Gloucestershire and Wales is likely to be closed for four days following a derailment.

A freight train carrying containers came off the tracks west of Gloucester station at 20:30 BST on Tuesday.

An empty container came off the wagon and "remains on the railway infrastructure". Nobody was injured.

The Rail Accident Investigation Branch said it was sending a team to the scene to determine how it happened.

The National Union of Rail, Maritime and Transport Workers (RMT) said the derailment was "deeply worrying".

"[It] suggests that the policy of cutting maintenance jobs and casualising key works out to private agencies and contractors is coming back to haunt transport services with a vengeance," the union said.

Network Rail said the RMT's view on the cause was "speculation".

Direct Rail Services, which was running the service, said recovery operations had begun to move the front of the train to a safe position.

The derailment caused debris to fall on a nearby road, British Transport Police said.

The police helicopter was called to help with the search for the container, which was found later.

The National Police Air Service tweeted it "certainly isn't something we look for on a regular basis".

Network Rail said the derailment was likely to cause problems until the weekend.

A spokesman said passengers heading towards Wales should travel to Bristol Parkway and change there.

Trains running towards Bristol and London are unaffected by the derailment.

This might have a knock on effect with other planned engineering work this weekend as London to South Wales services are due to operate via Gloucester.

A sensible move otherwise they might have had HST diversions up to Birmingham/ Shrewsbury and down the Heart of Wales line to Swansea !

The line between Lydney and Gloucester is likely to be closed for a few days. I bet there is going to be some disruption trying to get everything through the Severn Tunnel.

Suspended until Monday, according to National Rail Enquiries (NRE - is that in the Glossaty? :-))

NRES ... National Rail Enquiry Service

Wonder whether they are going to retime or will we hang around Newport on the way out and Swindon on the way back, maybe I'll make the earlier train at Reading but miss my pint.

Network Rail have cancelled engineering work this weekend so that services can travel through the Severn Tunnel.

I agree the website has been less than forthcoming.

Mind you they still haven't mentioned the franchise award yet which you would have thought was worthy of inclusion.

Looks like I may get to Cardiff on Saturday when I expected to.

The infrastructure damage west of Gloucester, is now expected to be repaired in time for the planned closing of the Seven Tunnel, this weekend, for engineering improvement work to go ahead. First Great Western services will run via Gloucester and Lydney as per the published amended timetable. Customers are advised to please check their journey before travelling.

EDIT: And re-reading my post and the quoted text (sic). Does anyone know where Tunnels One to Six are?  ::)

RAIB investigation - Gloucester derailment

The RAIB is investigating the derailment of a freight train that happened at around 20:15 hrs on 15 October 2013, on the approach to Gloucester on the railway line from Newport via Lydney.

The train comprised a class 66 locomotive and 14 twin container flat wagons, loaded with curtain sided containers. It was travelling at a speed of around 69 mph (111 km/h) when the rear axle of the rear wagon derailed around 4 miles (6.5 km) from Gloucester. The maximum permitted speed for this section of railway line was 90 mph (145 km/h) although the maximum permitted speed for this train was 75 mph (121 km/h).

The train driver was unaware of the derailment and the train continued with one axle derailed for a distance of around 3.8 miles (6.1 km) until, at Gloucester West junction, the derailed wagon collided with a set of facing points while travelling at 22 mph (35 km/h). Here both wheelsets were torn from the rear bogie and the empty container on the rear wagon was thrown off. The driver was slowing the train to comply with line speed restrictions and remained unaware of the derailment.

The train then continued towards Gloucester causing further damage to the track and wagon, damaging two bridges and throwing some debris onto a road below. As the train arrived into Gloucester station, the driver brought the train to a stand after he received an emergency message from the signaller over the cab radio system, calling for all trains in the Gloucester area to stop. The signaller had become aware of the derailment through damage to the signalling system. No one was injured as a result of this accident.

(http://www.raib.gov.uk/cms_resources/Gloucester-1.jpg)
Image of the derailed wagon outside Gloucester station

Examination of the line on the approach to the point at which the rear axle derailed, revealed evenly spaced dips in the rails which resulted in regular variations in the vertical height of the track; a phenomenon known as cyclic top.

(http://www.raib.gov.uk/cms_resources/Gloucester-2.jpg)
Image of the track on the approach to where the rear axle of the rear wagon derailed

The RAIB^s investigation will seek to identify the sequence of events leading to the derailment. It will consider how the track was maintained and why the train was permitted to run at a high speed over a section of track with cyclic top. It will also consider the design of the wagon and why the container fell off the wagon.

The RAIB^s investigation is independent of any investigation by the Office of Rail Regulation.

The RAIB will publish its findings, including any recommendations to improve safety, at the conclusion of its investigation. This report will be available on the RAIB website.

You can subscribe to automated emails (http://www.raib.gov.uk/publications/newsletter_subscription.cfm) notifying you when the RAIB publishes its report and bulletins.

Derailment near Gloucester 'on track with defect'

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Wheel sets were torn from the rear bogie and the empty container on the rear wagon was thrown off

A freight train that derailed near to Gloucester railway station was travelling at high speed on track with a minor defect, a report has shown.

The Rail Accident Investigation Branch (RAIB) is investigating the incident which happened on 15 October.

The line was closed for three days while a container that fell off a wagon was recovered and the track repaired.

The RAIB said the train had travelled for more than four miles before the driver realised anything was wrong.

The train, which had come from Newport via Lydney, was travelling at about 69mph (111km/h) when the rear axle of the rear wagon derailed about 4 miles (6.5 km) from Gloucester, the RAIB said.

Both wheel sets were torn from the rear bogie and the empty container on the rear wagon was thrown off.

The maximum permitted speed for the train on the section of track was 75mph (121km/h), the RAIB said.

A spokesman said there were evenly spaced dips in the rails which resulted in regular variations in the vertical height of the track - a phenomenon known as cyclic top.

A full investigation will consider how the track was maintained and why the train was allowed to run at a high speed over this section, the spokesman added.

The inquiry will also consider the design of the wagon and why the container fell off it.

A spokesman for Network Rail said time was needed to digest the report, and it was too early to comment on it.

Two sets of points, 300 sleepers, two miles of cable and a level crossing had to be replaced after the derailment. No one was injured.

Actually, what the Rail Accident Investigation Branch have published is not their report - they've simply set out the basis of their ongoing investigation.  ::)

Summary:

At about 20:15 hrs on 15 October 2013, a freight train operated by Direct Rail Services, which was carrying containers, derailed about 4 miles (6.4 km) south west of Gloucester station on the railway line from Newport via Lydney. It was travelling at 69 mph (111 km/h) when the rear wheelset of the last wagon in the train derailed on track with regularly spaced dips in both rails, a phenomenon known as cyclic top. The train continued to Gloucester station where it was stopped by the signaller, who had become aware of a possible problem with the train through damage to the signalling system. By the time the train stopped, the rear wagon was severely damaged, the empty container it was carrying had fallen off, and there was damage to four miles of track, signalling cables, four level crossings and two bridges.

The immediate cause of the accident was a cyclic top track defect which caused a wagon that was susceptible to this type of track defect to derail. The dips in the track had formed due to water flowing underneath the track and although the local Network Rail track maintenance team had identified the cyclic top track defect, the repairs it carried out were ineffective. The severity of the dips required immediate action by Network Rail, including the imposition of a speed restriction for the trains passing over it, but no such restriction had been put in place. Speed restrictions had repeatedly been imposed since December 2011 but were removed each time repair work was completed; on each occasion, such work subsequently proved to be ineffective.

The type of wagon that derailed was found to be susceptible to wheel unloading when responding to these dips in the track, especially when loaded with the type of empty container it was carrying. This susceptibility was not identified when the wagon was tested or approved for use on Network Rail^s infrastructure.

The RAIB also observes: the local Network Rail track maintenance team had a shortfall in its manpower resources; and design guidance for the distance between the wheelsets on two-axle wagons could also be applied to the distance between the centres of the bogies on bogie wagons.

The RAIB has made seven recommendations. Four are directed to Network Rail and cover reviewing the drainage in the area where the train derailed, revising processes for managing emergency speed restrictions for cyclic top track defects, providing track maintenance staff with a way of measuring cyclic top after completing repairs, and investigating how cyclic top on steel sleeper track can be effectively repaired. Two are directed to RSSB and cover reviewing how a vehicle^s response to cyclic top is assessed and amending guidance on the design of freight wagons. One is directed to Direct Rail Services and covers mitigating the susceptibility of this type of wagon to cyclic top.

The YouTube video from which the stills were taken on Page 45 can be found here.

https://www.youtube.com/watch?v=L4ntnt4DL60&list=TLW9k3I4Qf2zna7LqcyuZNlApThV-hz8IE (https://www.youtube.com/watch?v=L4ntnt4DL60&list=TLW9k3I4Qf2zna7LqcyuZNlApThV-hz8IE)

Scary stuff

the cost of fitting and maintaining derailment detectors
could not be justified on safety grounds alone. There was a better case for
fitment based on economic grounds, in terms of less infrastructure damage to
repair after a derailment

It's worth noting that in this particular incident if the wagon had derailed to the right, and there was a another train passing on the down line, the consequences of this cyclic top phenomenon could have been far worse.

One of the toughest, most highly technical, RAIB reports I've read. Hard work.

A technical question. In the days when Eurostar used to operate out of Waterloo, there used to be a bit of track just out of Waterloo where the train always ended up bouncing. Was that down to cyclic top - or something else?