Greater Wellington Regional Council
Lower North Island Rail Integrated Mobility new rolling stock
The overview
Greater Wellington Regional Council’s (GWRC) passenger rail service, Metlink, currently utilises 1950s-1990s diesel locomotives with ex-British Rail coaching stock for their regional services from Wellington to Masterton and Palmerston North. Given the advanced age of the rolling stock and the need to provide a more sustainable solution, GWRC had been in the process of developing strategies and solutions for replacement trains, as part of their Lower North Island Rail Integrated Mobility (LNIRIM) programme.
Our client's challenge
The regional services from Wellington along the North Island Main Trunk to Palmerston North and along the Wairarapa valley to Masterton provide essential commuter and leisure flows for inhabitants of the region. It has been recognised for some time that a better service could be provided, and demand for such a service exists, if new, more appropriate rolling stock was procured. Further, the locomotives used on the route pre-date any emissions regulations and are not a long-term sustainable solution. In addition, the trains operate under the overhead wires of the Wellington electrified network for a proportion of the journey. In 2021 GWRC embarked on a business case for the procurement of new decarbonised rolling stock. Passenger rolling stock procurement in New Zealand is not as frequent as other countries, and with only two previous procurements in the 21st Century, GWRC went to the market for procurement and decarbonisation expertise, and IPEX was engaged through RPS to provide rolling stock technical and commercial experts. Following the success of the business case, GWRC initiated the project to procure new rolling stock. IPEX was engaged, through WSP, to provide rolling stock and maintenance procurement expertise for the project.
- Decarbonisation
- Rolling stock procurement
- Strategy
- New Zealand railways
- Diverse teams working together over multiple time zones
The response
IPEX was part of a team of consultancies that wrote the detailed business case for the new rolling stock.
IPEX’s scope included developing a summary of all potential rolling stock solutions from locomotive hauled coaching stock to multiple units, a RAG analysis of those options to determine preferred outcomes; analysis of depot and stabling options to develop a proposed location, size, and equipment; and a review of maintenance requirements and options. IPEX then produced a whole life cost model to provide a financial comparison of the options.
Following the successful business case support, IPEX’s team led the creation of the vehicle specification and the market sounding, engaging with manufacturers over the requirements to ensure the client’s needs were met. This project had unique challenges due to the remote nature of New Zealand relative to rolling stock manufacturing hubs, and the small fleet size. IPEX guided GWRC through this process identifying opportunities to improve value for money while prioritising their operational requirements.
IPEX’s in-depth procurement expertise honed over decades of procurements, along with significant previous experience of New Zealand’s railways was vital to the development of the supply and maintenance agreements, where the IPEX team worked alongside the legal advisors bringing international precedent and best practice.
IPEX then fielded an expert team for the evaluation, working with the steering group to provide significant advice on the proposals presented by the manufacturers, and guiding the client to the most favourable outcome that matched the requirements. IPEX subsequently assisted with the development of the contract specifications and negotiations.
The value to the client
In September 2025, GWRC awarded a contract worth over NZ$1bn for the supply and maintenance of battery-electric multiple units, one of the most significant orders of battery-electric rolling stock to date.
During the business case, IPEX was able to bring its specialist knowledge in the advancements, and limitations, of the decarbonisation journey to GWRC, and ensure that the proposed solution would, not only provide the best value for money on completion, but would allow the rolling stock to be changed over the years as technology advances. This changed the client’s original solution of a bi-mode train to one fitted with batteries.
At the time of the procurement, whether the journey would be achievable only on batteries, or would require a diesel engine as well, was unclear with the technology advances suggesting it was possible but the market having not contracted delivery of rolling stock able to cover the required distances. IPEX utilised its deep-rooted expertise in procurement documentation development to produce a specification which enabled the manufacturer to offer whichever option was feasible, and enable changes later in the lifecycle.
IPEX’s experience with evaluation, both of rolling stock tenders, and of franchise and concession bids results in the team being adept at interpreting bid responses. In this case the IPEX team were able to advise and guide the client through the tender responses to ensure the chosen bid was suitable for the specific requirements of the New Zealand railways.