RSSB’s Rail Investigation Summary is a monthly collation of some of the world’s railway formal inquiry reports. It includes a brief incident synopsis, along with the main causes and recommendations from each investigation. Readers may find some of the actions and recommendations useful to their own operations.
Co-ordinated by Greg Morse, Operational Feedback Specialist, RSSB.
UK: Partial collapse of a bridge at Barrow upon Soar, 1 august 2016
For the full report, click here.
At around 23:50 on 1 August 2016, a bridge carrying Grove Lane, Barrow-upon-Soar, over the Midland Main Line, partially collapsed and a large volume of masonry fell onto the railway below.
At the time of the collapse, core sampling work was being undertaken to investigate subsidence in the footpath on the south side of the bridge. The bridge was closed to the public when the collapse occurred, but the railway lines below were open to traffic.
When the coring had reached about 1.4 metres below ground, water appeared at the surface. Shortly after, the adjacent wall fell away from the side of the bridge, taking with it part of the footpath, a length of cast iron water main and the core sampling rig. Five workers were able to get clear as the collapse occurred. There were no reported injuries.
Two of the four railway lines through the bridge were completely obstructed and there was debris on a third. There were no trains on the immediate approach to the bridge at the time of the collapse.
RAIB found that the incident occurred because the bridge wall, built around 1840, was not designed to resist overturning. It had also been weakened by a full- height vertical crack. The water main, which ran close to the vertical crack, probably had a slow leak which was causing on-going subsidence in the footpath. Prior to 1 August, however, there was no evidence that the wall was at risk of imminent collapse.
The coring work on the night of the incident disturbed the pressurised water main and it ruptured. The consequent release of water behind the wall quickly overloaded it and caused the wall to overturn about its base.
Underlying the incident was the fact that neither Network Rail nor framework contractor CML understood the risk to the bridge structure and to the open railway from the coring works.
As a result of its investigations, RAIB identified the following key learning point:
- Bridge examiners should record evidence of underground services, including water mains, and any changes since the previous examination, as required by Network Rail company standards, to alert bridge assessors and asset engineers to a possible connection between the water main and observations of defects on the bridge.
- Network Rail should:
- Identify in its structures database those structures that carry water (and other) utilities so that this information is readily available to its asset engineers, structures examination contractors, and minor works contractors;
- Provide training and guidance to its asset engineers and structures examination contractors so that they are able to identify the presence of water (and other) utilities in structures, recognise defects caused by leaks, are aware of the consequences of a major utility failure, and decide on appropriate actions to be taken;
- Introduce a requirement in its procedures to notify the relevant utility company about any emerging problems which might affect the integrity of a structure, to enable early remedial action and prevention of further deterioration; and
- Re-brief its asset engineers and structures examination contractors on the importance of recording evidence of underground utilities and any changes since the previous examination, as required by current Network Rail company standard
- Network Rail should:
- Review how it procures intrusive works to its structures carrying water (and other) utilities, and verify that the process provides for sufficient input by suitably qualified engineers to assess the risk to the structure from the proposed works;
- Review its process for determining the appropriate level of competence for site supervision of the works; and
- Address any deficiencies found
- CML should undertake a review of its management processes for the planning and execution of works on structures that carry water (and other) services. This should include the training, competence and supervision of operatives that may be required to locate pipework. CML should then implement a programme to deliver the identified improvements and to monitor its effectiveness.
Australia: safe working irregularity near jumperkine, wa, 29 September 2015
For the full report, click here.
On 29 September 2015, a freight carrying bulk grain was travelling from Avon Yard to the port at Kwinana in Western Australia, when it exceeded its limit of authority. On that day, track re-railing works were in progress along the route, requiring the closure of the Up Main line between Moondyne and Jumperkine. The closure resulted in the diversion of train movements to the adjacent track and the implementation of single line block working under the rules applicable to train order working.
The crew received a train order to proceed from Moondyne to the ‘station limits board’ at the 48 kilometre location, where they were to stop. Attached to the train order was an additional instruction relating to tasks required when approaching the worksite beyond that point. After accepting the train order and leaving Moondyne, the train crew continued to discuss the additional instructions relating to the tasks required when passing the worksite.
As the train approached the 48 kilometre location, the crew observed a station limits board and a track closed warning device that marked the limit of the authority. With little time to respond, the driver applied an emergency brake application. The train collided with the track closed warning device before coming to a stop approximately 400 metres past the limit of authority. There was no imminent risk of collision with people or other rail traffic, as the distance separating the train and the worksite was approximately 4 kilometres.
The Australian Transportation Safety Bureau (ATSB) found that the additional instructions attached to the train order distracted the crew from their principal task, which was to stop at the 48 kilometres location. The ATSB also found that there were no visual cues to alert train crew that they were approaching the limit of their authority.
Brookfield Rail erected non-crossing indicator boards on each approach to the station limits board. Additionally, safeguards to protect the worksite were increased to include extra infield protection at either end of the closed section of track.
In March 2016, Brookfield Rail also introduced a new suite of safe working rules and procedures consistent with the Australian Network Rules & Procedures.
Communication of information through non-standard practices and/or the addition of information irrelevant to the intended task may reduce clarity and introduce a source of distraction.
In an operational environment, effective communication, cross-checking and shared understanding by train crew, together with appropriate environmental cues, contribute to ensuring the effective performance of tasks.
us: passenger train collision with locomotive at brentwood, arkansas, 16 october 2014
For the full report, clink here.
At 10:25 (local time) on 16 October 2014, a northbound Arkansas & Missouri Railroad Company (A&M) locomotive collided with a stationary southbound A&M excursion train in Brentwood, Arkansas.
The excursion train had stopped because it had lost track adhesion and was not able to move up the 1.1% gradient.
The locomotive had travelled north to rescue the excursion train, but struck it at around 24 mph. Thirty-nine passengers and four A&M employees were taken to local hospitals and medical centres with non-life-threatening injuries.
One of the damaged carriages released about 40 gallons of diesel fuel from a generator fuel tank, but the fuel did not ignite.
The National Transportation Safety Board (NTSB) determined the probable cause of the accident to be the failure of the rescue locomotive’s crew to comply with the restricted speed requirement that limited linespeed to no more than 20 mph and their failure to be prepared to stop within one-half the range of vision when approaching the excursion train.
The NTSB also found ‘informal communications of the train dispatcher and both train crews’ to be a contributory factor.
- None issued