Auckland City Rail Link Safety Assurance

03 Mar 2025

Background

KiwiRail is a New Zealand state-owned rail enterprise, providing passenger and rail freight services, as well being responsible for the operation and maintenance of national rail infrastructure. Acting as the Rail Access Provider, KiwiRail provides train control and access for third party Metro Service Operators (MSO) to operate upon the same network. They are the future owner and operator of the Auckland City Rail Link (CRL) system, an urban underground metro link which enables the ability to significantly increase capacity of the wider Auckland Rail Network by connecting the previously terminus Britomart station, to Mt Eden junction via new twin metro tunnels and two new underground stations in the heart of the Auckland CBD.

Auckland City Rail Link

Auckland CRL presents an entirely new operational context for KiwiRail (both underground metro plus the increased traffic), to which it must act as both a ‘Rail Operator’, ‘Network Access Provider’, and Infrastructure Owner. As such, it requires the existing KiwiRail Safety Case to be formally varied through a Safety Case Variation (SCV), and all associated safety assurance to be undertaken and evidenced in a formal submission to New Zealand Transport Authority (NZTA) – New Zealand’s rail regulatory body. NZTA must approve the SCV before trains are permitted to run on the CRL portion of the network for both Testing & Commissioning (T&C), and later passenger revenue services.

In addition to this, KiwiRail are what is considered a Stakeholder Alliance Participant (SAP) to the CRL project delivering the new system. CRL Limited (CRLL) was created to provide independence from the local council and central government that both provided funding for the project. CRLL effectively act as the client with the Link Alliance (group of companies) (LKA) formed to deliver CRL design and build. The eventual owners and custodians of the asset are stakeholders to the project (SAP), and provide input, feedback, and decision-making power at certain milestones related to whether the project can continue to the next stage or not.

Approach

With respect to KiwiRail’s role and responsibility as an SAP, Shoal provided comprehensive understanding of the CENELEC EN50126 standards (and other related standards) which are being used to inform the systems & safety engineering methodology employed on the project by CRLL and LKA. Shoal used this knowledge to review and provide guidance to KiwiRail against the many artefacts and evidence provided by the project to SAP for review and feedback, to mitigate risk of a system being delivered that was unsafe or not fit for purpose. Shoal was contracted to support and enhance KiwiRail’s capability, increasing capacity and sharing our comprehensive understanding of these standards, to help them perform their role as an SAP, effectively.

Shoal was also contracted to provide the leadership and design for the necessary Safety Case Variations, which are on the project’s critical path. These SCVs demonstrate that KiwiRail as a business, and CRL as a system operated in conjunction with the broader network, were safe So Far As Is Reasonably Practicable (SFAIRP) to proceed against a holistic set of considerations – first into T&C and later (2026) into passenger revenue services.

Solution

Shoal provided expertise to lead the development and delivery of a Safety Case Variation submission to the regulator, as well as provided review and feedback with respect to systems engineering, safety assurance, and our understanding of the standards to KiwiRail on deliverables and milestones delivered by CRLL and LKA.

Example activities led by Shoal included:

Design and project management of the overarching approach and execution to achieve on time successful SCV submission and approval.
Managed CRL SCV scope and interfacing elements of other projects and their associated SCV.
Develop the Goal Structured Notation (GSN) to communicate the high-level structure and content of the safety argument to stakeholders who need it.
Developing overarching narrative to successfully communicate and gain up front buy-in from internal stakeholders, the project organisations, and NZTA, the rail regulator.
Risk workshop facilitation, analysis, data traceability, and risk/control allocations and sign-off.
Lead and facilitate development of SFAIRP analysis and determinations for system, network, and timetable.
Review and feedback of all safety or system related project documentation against relevant standards.
Safety gate attendance with advice to KiwiRail gate board member.

Outcomes

Shoal delivered KiwiRail’s most holistic and comprehensive safety case variation to date, which was fully accepted by the regulator without additional information needed. This enabled the project to proceed into T&C and keep KiwiRail’s readiness and safety case requirements off the project’s critical path.

About Shoal

Shoal is complex systems design company. We use Systems Engineering combined with Modelling, Simulation and Analysis to help our clients define, analyse, decide, optimise, and deliver technology-intensive projects in complex environments across Defence, Space, Transport, Energy and Infrastructure.

More: shoalgroup.com