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Management of risk associated with poor adhesion

Issue number: RO-2013-005-SI-01
Who it affects: All owners and operators of rolling stock fitted with electro-pneumatic disc actuated braking systems incorporating wheel slip-slide protection control.
Issue owner: Queensland Rail Limited
Operation affected: Rail: Passenger - metropolitan
Background: Investigation Report RO-2013-005
Date: 20 December 2013

Safety issue description

Queensland Rail’s risk management procedures did not sufficiently mitigate risk to the safe operation of trains in circumstances when local environmental conditions result in contaminated rail running surfaces and reduced wheel/rail adhesion.

 

Response to safety issue by Queensland Rail

Queensland Rail provided a response on 1 March 2013 detailing the initiation of the following targeted precautionary mitigation strategies in response to the collision of train T842 at Cleveland Station on 31 January 2013.

  • The formation of a Wheel Rail Interface Working Group. The Working Group, sponsored by the Executive General Managers - Rail Operations and Safety, Assurance and Environment, is tasked to specifically identify and assess any potential wheel rail interface risks, particularly for Queensland Rail’s fleet of 160/260 class trains being operated in certain conditions, and to determine if any further engineering, administrative or other safety risk controls should be considered and implemented.

The Working Group comprises a range of internal and external stakeholders including rolling stock, rail network, and train service delivery engineers, technicians and managers; key rail union representatives from the Rail Tram and Bus Union and Australian Federated Union of Locomotive Employees; and an experienced independent rail safety risk management consultant. The Working Group is also supported by a range of subject matter expertise

including for program, risk, safety and human resource management and train manufacturer Bombardier. It is important to note that Queensland’s Rail Safety Regulator also has a nominated observer on the Working Group to ensure Queensland Rail continues to effectively manage its rail safety risks.

The Working Group’s key deliverables, as outlined within its Terms of Reference are to develop:

  • A list of evidence based hazards and the likelihood of future risk associated with 160 and 260 class units
  • A plan of control, addressing future risk, prioritised and classified as short, medium and long term controls
  • Any plan of control needs to provide mitigation strategies which focus on safety, customer service and service continuity.

One of the Working Group’s first tasks was to develop a comprehensive risk assessment of any potential wheel rail interface issues for the 160/260 class of trains operating on the network and their associated safety risk controls. The risk assessment was independently validated and recommended a number of precautionary risk controls to be adopted, in addition to existing controls, whilst further medium and longer term testing and assessments continued. These precautionary risk controls include:

  • Identify and treat track rail-head contaminants at any localised black spot locations.
  • Build track contaminant risk identification into routine track inspection processes to help inform track gangs to be on the lookout for related contaminants.
  • Assess whether current vegetation control processes have the potential to cause or contribute to contamination of the rail.
  • Ensure there are no parts of the network where train crews are exposed to acute reductions in line speed without receiving advance graduated speed reduction notice.
  • Provide train crews of 160/260 fleets with enhanced train handling advice that when approaching stop signals and other critical points, that they should aim to reduce speed to 50% of line speed when observing a single yellow signal and, not exceed 30 km/per hour when within 150 metres of red signals/critical stopping points, unless a lower speed is indicated, in which case the lower speed applies.
  • Review current driver training processes and adapt training materials to specifically address any identified class 160/260 unique characteristics.
  • Encourage train crew to report all excessive wheel slip occurrences on 160/260 fleet.
  • Monitor and further analyse data logger information of trains, as per new explanatory procedure if they are subject to an excessive wheel slip occurrence.
  • Continue research to ascertain whether 160/260 class train brakes are releasing long enough in wheel slip scenarios for the wheel sets to recover prior to the brake system reapplying brakes.
  • Research wheel cleansing modification opportunities.
  • Review planned new generation rolling stock specifications to ensure current wheel slip lessons learnt are considered.
  • Review train crew training around:
    • Known fleet specific hazards and fleet characteristics; and
    • Defensive driving techniques

Queensland Rail’s Executive General Management had no hesitation in accepting all of these recommended precautionary controls and ordered their immediate implementation.

  • Queensland Rail continues to test and assess wheel rail interface risks around its 160/260 class fleet including reviewing what possible further controls should be implemented.
  • In addition to these wheel rail interface controls and processes, Queensland Rail also provided a Critical Safety Alert to staff regarding the importance of both providing and following documented Safety Management System instructions whenever an incident is or may be impacted by overhead electrical infrastructure.

Queensland Rail also continues to fully support and coordinate with the ATSB in its ongoing investigation.

 

ATSB response:

The ATSB notes that Queensland Rail is in the process of implementing its precautionary mitigation strategies to provide for the safe operation of rolling stock but the residual safety risk remains significant and further action is required.

Recommendation

Action organisation: Queensland Rail
Action number: RO-2013-005-SR-001
Date: 13 March 2013
Action status: Monitor

The ATSB recommends that Queensland Rail take action to mitigate risk to the safe operation of their trains in circumstances when local environmental conditions result in contaminated rail running surfaces and reduced wheel/rail adhesion.

 

Correspondence

Date received: 24 May 2013
Response from: Queensland Rail
Action status: Monitor
Response text:

The Australian Transport & Safety Bureau (ATSB) identified in its Preliminary Report that “Queensland Rail’s risk management procedures did not sufficiently mitigate risk to the safe operation of trains in circumstances when local environmental conditions result in contaminated rail running surfaces and reduced wheel/ rail adhesion”. As a result, the ATSB recommended that “Queensland Rail take action to mitigate risk to the safe operation of their trains in circumstances when local environmental conditions result in contaminated rail running surfaces and reduced wheel/ rail adhesion”.

Actions taken by Queensland Rail:

As soon as Queensland Rail became aware of possible wheel rail interface issues with its 160/ 260 fleet, it immediately implemented a range of precautionary mitigation strategies and actions to provide for the safe operation of rollingstock.

These actions relate to:

  1. Targeted rolling stock testing
  2. Data analysis of previous and future wheel slide occurrences
  3. Trialing of sanders on the 160/ 260 fleet
  4. Developing procedures to return affected rollingstock back into service
  5. Identifying black spot locations of wheel slide safety occurrences throughout the Network
  6. Analysing track contaminants
  7. Implementing vegetation control measures to prevent contaminated rail
  8. Reviewing and updating current training regarding wheel slide
  9. Developing procedures for responding to wheel slide safety occurrences.

The following text details actions and the current status

ROLLINGSTOCK

Testing of Rolling stock

Action - Analysing track adhesion to determine contaminant and likely sources of supply to be applied during on track testing.

Status - Initial testing was conducted in February 2013, with the ATSB and Unions present, which highlighted no braking issues with the 160/ 260 class vehicles. Further on track testing is to be conducted around June 2013. Testing of 160/ 260 class vehicles to model WSP behaviour with a view to advise on driving operations, performance of WSP at low adhesion levels and to investigation optimisations.

Action - Testing plan/s to be finalised in May/ June 2013. On track testing to be conducted around June 2013.

Status - Testing of other class vehicles to model WSP behaviour with a view to making comparisons with 160/ 260 class vehicles.

Action - Testing plan/s to be finalised in May/ June 2013.

Status - On track testing to be conducted around June 2013.

 

Data Analysis of Safety Occurrences of all Suburban Rolling stock

Action - Analysing safety occurrence data (including station overruns by location, station overruns by fleet type, signals passed at danger and slip or brake related safety occurrences) covering seven years from January 2007 to February 2013.

Status - Completed in February 2013.

Action - Monitoring and further analysis of data logger information after all wheel slide safety occurrences.

Status - Ongoing.

 

Trialing Sanders on Rolling stock

Action - Proposing trial and fitment of sanders (or equivalent) to rolling stock.

Status - Negotiating with the fleet manufacturer in regards to a business case to trial a sanding system on 160/ 260 class vehicles.

Action - Evaluating cost/ trial/ fitment of scrubbers (or equivalent) to rolling stock.

Status - Negotiating with fleet manufacturers in regards to other engineering options to increase adhesion including the trialling of scrubbers.

 

Development of Procedural Documentation to Return Affected Rolling stock into Service

Action - Development and independent validation of procedures

Status - Certificate issued. Completed in April 2013.

 

Development of Specifications Relating to Wheel Slip Lessons for New Generation Rolling stock

Action - Reviewing and amending current brake specifications.

Status - Addendum issued. Completed in April 2013.

 

INFRASTRUCTURE

Identifying Black Spot Locations Based on History of Wheel Slide Safety Occurrences

Action - Examining track in Black Spot Locations by track gangs during routine inspections.

Status - Completed in March 2013.

Action - Building contaminant risk identification into track gang routine inspection processes.

Status - Ongoing.

Action - Identifying and treating contaminants in Black Spot Locations.

Status - Completed in March 2013.

Action - Identifying locations with acute speed reductions.

Status - Completed in April 2013.

Action - Discussing Black Spot Locations with affected staff in the form of Toolbox Talks.

Status - Completed in March 2013.

 

Implementing Vegetation Control Measures To Prevent Contamination of the Rail

Action - Identifying heavily vegetated areas and species present in the area using aerial survey or other means.

Status - Ongoing.

Action - Changing current relevant business instruction to ensure a clean-up and inspection of rail is undertaken at the completion of tree clearing operations.

Status - Completed in March 2013.

 

Analysis of Track Contaminant

Action - Obtaining track samples from wheel slide safety occurrences locations

Status -  Completed in February 2013.

Action - Testing of track samples taken from wheel slide safety occurrences locations to identify contaminant.

Status - Completed in March 2013.

Action - Determining how to replicate contaminant in a controlled situation.

Status - Completed in March 2013.

Action - Replicating contaminant and undertaking testing to rolling stock.

Status - Completed in April 2013.

 

Researching Track Contaminant

Action - Carrying out contaminant academic research.

Status - Liaising with Universities on literature available in regards to contaminants. Further testing of adhesion measurements to be conducted around June 2013.

 

OPERATIONS

The Reporting of All Wheel Slide Safety Occurrences on the 160/ 260 Class Vehicles

Action - Developing a Business Instruction on how to respond to all wheel slide safety occurrences.

Status - Completed in March 2013.

Action - Encouraging the reporting of all wheel slide safety occurrences on the 160/ 260 class vehicles.

Status - Ongoing.

 

Reviewing and Updating Current Training Regarding Wheel Slide

Action - Review and update related current training

Status - Completed in March 2013.

Action - Developing, piloting and launching a Guide on the braking system for 160/ 260 class vehicles for Rail Traffic Crew. This Guide is to explain how the braking system on the 160/ 260 class vehicles works and what Rail Traffic Crew are to expect during wheel slide situations.

Status - Completed in March 2013.

 

Providing Specialised Training for 160/ 260 Class Vehicles Unique Characteristics

Action - Reviewing of processes and adapting training material.

Status - Completed in April 2013.

Action - Ensuring Appropriate Training Around Fleet Specific Hazards and Fleet Characteristics and Defensive Driving Techniques

Status - Completed in March 2013. A training course, video and Special Operational Instructions were developed. The specialised training is now integrated in all new Drivers training. Two new driver schools are currently being undertaken. It is expected that all CityTrain Divers will attend and complete this course around June 2013.

Date received: 02 December 2013
Response from: Queensland Rail
Action status: Monitor
Response text:

Queensland Rail has implemented a procedure for Network maintenance staff to identify, treat and prevent rail contaminants at source. Network Control are advised when contaminants are identified and these are removed as soon as it is safe and practicable to do so. The procedure has been communicated to relevant Queensland Rail staff and a cross-divisional standard has been implemented which details the specific actions required whenever a wheel slide occurs and/or rail contaminants are identified.

Queensland Rail is currently trialling a sanding system on a 3-car unit to determine whether this technology mitigates the risks of wheel slide by improving adhesion at the wheel rail interface. Stage 1 of the testing is now complete with a preliminary report due for completion in December 2013. Pending results of the trials, Queensland Rail anticipates calling tenders for the supply and fitment of a sanding system to railcars by the end of January 2014.

ATSB response:

The ATSB notes that Queensland Rail trialling a system to mitigate the risk of reduced wheel/rail adhesion due to environmental conditions, but the solution is yet to be fully implemented.

The ATSB is satisfied that the action proposed by Queensland Rail will, when complete, adequately address the safety issue. The ATSB will monitor the progress of the proposed safety action.

   
Current issue status: Safety action pending
Status justification:

The implementation by Queensland Rail of the Wheel Rail Interface Working Group recommendations ongoing.

 
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Last update 25 February 2015