Thursday, July 21, 2022

Safety message: The Dangers of Reprioritising Defects

ONRSR conducts regulatory activities, including audits, inspections and site visits, across multiple operators and sectors. In conducting these activities, ONRSR often observes and identifies common safety themes and issues.

In this series of safety messages, ONRSR highlights these issues, how they can potentially increase risks to rail safety and what better practice can look like to minimise the potential risks.

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#2 Reprioritising defects to provide additional time for rectification

Operators have been found to reprioritise identified defects e.g. reclassifying a ‘type 1’ defect as a ‘type 2’.

The practice of reprioritising a defect is an inherently dangerous way to extend the time that an operator has to rectify or fix the defect. In all such scenarios, there is potential harm that can arise.

Fundamentally, if there are no other controls in place, and a defect is not fixed within the set timeframe, the defect(s) can become worse, more frequent, or fail catastrophically. For example:

  • A track fault is reprioritised– instead of it needing to be fixed in 2 months, it is delayed for 6 months. No additional controls, such as temporary speed restrictions, are put in place and no monitoring is put in place to ensure the defect does not become a safety issue. The defect results in misalignment causing a derailment.

Operators must consider a range of factors, including the likelihood of the hazard and the degree of harm to determine what controls are reasonably practicable to implement (see the ONRSR Guideline – Meaning of duty to ensure safety so far as is reasonably practicable SFAIRP for more information).

The following includes, but is not limited to, what good practice can look like:

  • Authorisations are in place to ensure that there are appropriate approvals for any delay in rectification works; the reprioritisation is signed or agreed by the appropriately competent person.
  • Processes and procedures are in place to govern how defects are reprioritised e.g. RISSB guideline classification of wheel defects – provides the criteria when a defect is found in service and how long it can stay in service.
  • Monitoring and regular review of the defect itself occurs if the corrective action is delayed.
  • Objective evidence such as quantified data is used rather than subjective evidence to inform decisions about whether or not the defect is reprioritised, or the corrective action is delayed.
  • Deadline or due dates exist for when the defect will be rectified rather than ‘when rectified’ or making extensions upon extensions.
  • Resourcing is appropriately allocated, including people, plant and equipment, and scheduling, so that defects can be fixed according to the timelines in the SMS.
  • Maintenance is preventative and planned rather than reactive to ensure defects are fixed before they become an issue.

By pursuing good practice, operators’ railway operations can benefit in the following ways:

  • Provides evidence of decision-making should this be scrutinised in the future.
  • Ensures there is appropriate objective evidence to support decision-making.
  • Ensures resources can be prioritised for defects which present the greatest safety risk.

As a result of this safety message, operators may benefit from reviewing their SMS. The following list includes, but is not limited to, those systems and procedures likely to be most relevant for review:

  • Technical Maintenance Plans
  • Management of change process
  • Monitoring processes and procedures
  • Training processes, competency requirements and assessments
  • Corrective action systems and procedures

This information is provided as guidance only and may not be applicable to all rail transport operators.


A comprehensive collection of ONRSR Safety Messages is available to view here.

Last updated: Jan 11, 2023, 11:18:50 AM