A function of the rail safety regulator is to identify the safety issues that have caused a specific incident or series of incidents to occur. Statutory investigations require in-depth, independent examination of an event or series of events to identify failures that must be addressed to prevent reoccurrences.

The Rail Safety team conduct investigations in a systematic and methodical way to ensure that they are thorough and evidence based. Investigations are independent and impartial in the best interests of rail safety.

Initiating an investigation

An investigation may be initiated through a range of circumstances, including the following:

  • A notifiable occurrence (accident or incident) concerning a rail participant
  • The targeting of specific areas of risk – identified through incidents or trends
  • Arising from information received by the Transport Agency. 

Investigation objectives

The objectives of an investigation are to:

  • Establish the facts relating to an incident, event or situation
  • Determine the compliance with legislation or recommendations
  • Determine the appropriate enforcement response or actions that can improve safety outcomes.

Investigation process

In selecting what incidents, events or situations  to investigate, the Rail Safety team will take account of the following factors:

  • The seriousness of any actual or potential breach of the legislation
  • The severity and scale of any actual or potential harm.
  • The past compliance history of the rail participant.
  • Whether the actual or potential harm relates to a priority on the national priorities programme.
  • The wider relevance of the event, including whether the matter is in the interest of public good.

Undertaking an investigation

Investigations generally consist of:

  • Determining the scope of the investigation
  • Planning and preparation
  • Gathering information and collating evidence
  • Utilising experts and specialists
  • Evaluating and analysing the evidence and information collected
  • Reporting findings

Actions taken following an investigation

There are a number of tools and functions available to the Rail Safety team following an investigation. The decision on what action to take is determined by consideration of a number of factors including:

  • The impact and associated consequences of the associated risk
  • The likely effectiveness of each tool
  • The timeliness and quality of resolution
  • The participant's history of compliance and incidents

The Rail Safety team investigation process can be summarised by the following diagram which covers key stages.

Figure 1. Investigation process

Investigation process

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Working with other agencies

Many rail investigations are conducted concurrently with another agency or organisation, depending on the nature of the investigation. In particular, Transport Accident Investigation Commission (TAIC), New Zealand Police and/or Work Safe may be investigating the same incident or event. Where possible the Rail Safety team work with other agencies to minimise the impact and uncertainty of affected parties to ensure optimal usage of resources.