The section of track between Westfield and Wiri is one of the most heavily used in the entire country. On top of serving both the Southern and Eastern lines, it is also sees more rail freight pass over it than any other stretch of track in NZ. It’s so busy that Kiwirail have declared “the current twin track configuration has reached the maximum operational capacity”“. That lack of capacity is resulting in delays to both passengers and freight. It’s long been known that the best solution to the issue issues between Westfield and Wiri is to build a third track to improve capacity. Yet bizarrely, the project still hasn’t been funded.
We wanted to see just how strongly the project stacked up and so a few months ago Harriet asked for a copy of the business case through an Official Information Act request. Things went to another level after it hit the news that the Transport Minister’s office tried to block Kiwirail from releasing the document. Kiwirail subsequently released it but only after first heavily redacting much of the key information in the report, although they left enough we could ascertain the project stacked up well. This week, likely in response to a review of the situation by the Chief Ombudsman, Kiwirail released the full, almost fully un-redacted business case.
Reading through the document, the reason for the Ministers office to want to hide the document becomes clear. That’s because it’s likely the only thing worse than realising you need to be build one extra rail line is being told you need to build two of them. In this case that means both a third and fourth line on this section of track. All mention of a fourth track had been previously been redacted, leading to much speculation as to what was hidden in the document.
The report lays out a multi criteria analysis to look at the differences between each of the options proposed. There are some definite issues with the MCA, such as rating the affordability of both the third and fourth mains the same, but as you can see, in it the 4th main comes out as the strongest across almost all metrics.
Unlike the third main, the fourth main would be built on the eastern side of the existing tracks. Of course, it’s not going to easy to get a fourth main built. It would likely mean that many bridges and potentially stations along the route would need to be rebuilt. As such, the biggest argument against the fourth main is really the cost, with the case suggesting it could be up to $200 million.
Despite getting the best ranking, the report shy’s away from recommending the fourth main be built by saying it would “create capacity in advance of demand”. Given Auckland’s history of only building infrastructure too little too late, why building the fourth main in advance is perceived by our agencies as such a bad thing isn’t clear. However, given it’s clear we’ll need it some way, it is noted that “The 4th Main will be almost certainly be required in the medium to long term horizon“. As such, it suggests that perhaps some parts to support a 4th main could be built at the same time.
However, it is noted that building the 3rd Main and 4th Main (or some component parts) together could result in cost synergies and as a minimum it would be prudent to ensure any land purchases made for the 3rd Main also take account of the 4th Main too.
If the costs listed above are to be believed I do wonder if we should just bite the bullet and do both mains at the same time. After all, $200 million is a medium sized motorway project these days and this is something that we’re definitely going to need – and given recent history, we’ll need it much sooner than the transport models suggest. It could also give us opportunities to try out other service patterns and/or things such as intercity trains.
Even with just the third main to build, and Kiwirail say the design work is “reasonably well advanced“. They say is will need to be built:
Completion of the 3rd Main Line between Westfield Junction and the Wiri Inland Port requires the following new infrastructure:
- New section of 3rd track Middlemore to Puhinui (3.6km)
- Manukau Junction high-speed crossovers
- A third platform at Middlemore Station, designed to take account of future hospital plans
- A land exchange with Counties Manukau District Health Board for the 3rd Main Line. (Any negotiations around a land exchange should also take full account of the requirements fora a 4th Main.)
- Overhead wiring and signalling changes across full scheme
- Track works between Wiri and Manukau Junction.
While this diagram shows where the investment is going, with the majority into the Middlemore to Puhiniu section.
It’s good to finally have the full document but it should never have been redacted in the first place. Further, if the models are already saying we’ll be needing the extra capacity of a fourth main in 10-15 years then we might as well build it now.