Safety issues at rail level crossings are a key concern for TSV, the Victorian Government, the wider rail industry and the community. Upgrades to level crossing protection are expensive and compete with other important projects for limited government resources. Therefore, new ways to improve safety at level crossings are a high priority. New and innovative countermeasures are proposed at regular intervals, and the implications of these for road user behaviour and level crossing system safety must be assessed systematically.
In recognition of the safety issues at level crossings, the Monash University Accident Research Centre (MUARC) received funding from the Australian Research Council to conduct research on human factors issues at level crossings. The research is a partnership between MUARC and a number of organisations that are providing funding or in-kind support for the project. The organisations are:
-
TSV
-
VicTrack
-
Department of Transport (DOT)
-
V/Line
-
VicRoads
-
Transport Accident Commission (TAC), and
-
University of Southampton (in the United Kingdom)
In June, 2010, Monash University received funding for the project, entitled Application of contemporary systems-based methods to reduce trauma at rail level crossings.
This research will be conducted over four years and aims to develop a systems-based model of railway level crossing performance that accounts for road user behaviour, the factors that influence road user behaviour (such as signage, the types of protection provided, the sighting distance on the crossing etc.), and the factors known to lead to incidents and accidents. The model will be used to prioritise current and new countermeasures. A proportion of these will be formally tested using additional methods of assessment.
The knowledge developed during the project will include a world-first model of the level crossing system and will support the development of countermeasures that will improve safety. TSV looks forward to the findings of the research and seeing these implemented into practice.
Failure of bridges due to scour
Scour is the loss of foundation material (i.e. soil and rocks) from around bridge abutments or piers caused by the flow of water over time. It can lead to the undermining of bridge foundations and has been the cause of numerous catastrophic bridge failure incidents.
Recent incidents that have identified scour as the main causal factor include the River Crane Bridge collapse in UK (November 2009) and the Malahide Viaduct collapse in Ireland (August 2009).
River Crane Bridge collapse UK
The Rail Accident Investigation Branch (RAIB), Rail Accident Report5, identified the following contributing factors: -
-
an obstruction in the watercourse, which channelled the flow towards the east abutment, increasing its velocity and making it more likely that scour would occur;
-
Network Rail being unaware of the obstruction and therefore not taking action to mitigate the risk of scour;
-
the vulnerability of the east abutment of the bridge to undermining by scour by virtue of being located on the outside of a bend in the river, constructed with shallow foundations and founded on erodible material;
-
the absence of checks by Network Rail staff for obstructions against the upstream faces of bridges;
-
weaknesses in Network Rail’s process for annual assessments of structures, particularly the information provided to the individuals involved;
-
Network Rail having inadequate knowledge about the condition of the foundations of the bridge as they had not commissioned mandatory underwater examinations;
-
the lack of a mechanism to encourage members of the public who were aware of the obstruction to report it to Network Rail; and
-
Environment Agency staff not being aware of the safety risk presented by the obstruction found in the watercourse at the bridge and not being under an obligation to report non-flood risks to the infrastructure owner.
As a consequence of this accident the RAIB made five recommendations to Network Rail as summarised below:
-
mandating frequent checks for obstructions against the upstream faces of bridges;
-
improving the annual assessment process for structures to ensure that key personnel have sufficient information to undertake the task competently. The river crane report found it was unreasonable to expect scour to be detected by track patrollers undergoing routine inspections;
-
introduction of a means to prompt members of the public to report obstructions;
-
improvements in Network Rail’s process for managing scour risk; and
-
improvements in the guidance provided by Network Rail to staff who may have to evaluate whether it is safe to run trains in the immediate aftermath of an incident.
The RAIB has also made one recommendation targeted at the Environment Agency covering the introduction of arrangements for reporting obstructions to railway infrastructure owners, regardless of whether there is a risk of flooding.
Malahide Viaduct Collapse Ireland
The Railway Accident Investigation Unit (RAIU) in Ireland, Investigation Report ‘Malahide Viaduct Collapse on the Dublin to Belfast Line, dated 21 August 20096, identified the following contributing factors:
-
the infrastructure manager (IM) had not developed a flood/scour management plan
-
engineers were not appropriately trained for inspection duties, in that the inspections training course they completed was an abridged version of the intended format, and there was not formal mentoring programme, for engineers on completion of this course
-
there existed an unrealistic requirement for patrol gangers to carry out annual checks for scour, as they do not have access under the structure and in addition, they did not have the required specialist training/skills to identify defects caused by scouring
-
the IM’s suite of structural inspection standards providing guidance for inspectors carrying out inspections was not formalised
-
there existed an unrealistic requirement for patrol gangers to carry out annual checks for scour, as they do not have access under the structure and in addition, they did not have the required specialist training/skills to identify defects caused by scouring
-
a formal program for special inspections for structures vulnerable to scour was not adopted, as per the infrastructure manager’s inspection standard at the time of the accident.
The report also stated that the underlying factors to the accident were:
-
loss of corporate memory when the IM’s staff left the division, which results in valuable information to the historic scouring and maintenance not being available to the staff in place at the time of the accident
-
information regarding the bridge was missing due to there not being a properly introduced information asset management system
-
the IM failing to meet all of the requirements of its inspection standard: visual inspections were not carried out for all visible elements of structures, bridge inspection cards for recording findings of inspections were not completed to standard or approved by the relevant personal. A formal programme for systematic visual inspections of all elements of a structure, including hidden or submerged elements, despite an independent review recommending the IM implement this programme in 2006.
The RAIU made 15 recommendations, some of which are summarised below. The full list of recommendations can be found in the investigation report.
-
The IM should remove the requirement for track patrollers to check for scour
-
The IM should formalise their guidance standard for inspections and reissue to all relevant personnel.
-
The IM should introduce a verification process to ensure that all requirements of their standard are carried out in full.
-
The IM should carry out inspections for all bridges subject to the passage of water for their vulnerability to scour, and where possible identify the bridge foundations. A risk-based management system should then be adopted for the routine examination of these vulnerable structures.
The factors listed above contributing to the bridge collapse due to scour highlight the importance of assessing and managing risks associated with scour. It can be difficult for bridge inspectors to check for scour during scheduled bridge inspections due to access difficulties, and the possibility of infilling i.e. the void created by scour has been filled by loose soil and sediment making the void appear filled. IM’s are therefore advised to implement a scour risk management plan as part of their bridge Inspection regime.
Share with your friends: |