In November I made a request under the Official Information Act regarding any potential Third Main business case, as it was one of my ATAP ASAP’s and I wanted to know if any movement had been made, especially as it was mentioned in ATAP & the agencies had gone quiet on the issue.

The response I received back confirms one exists, it is in draft form pending approval from KiwiRail & the Minister.

You can see the full response from the NZTA here

What is the Third Main?

Third Main Slide
Share this


  1. Unbelievable how decision-makers have dithered and procrastinated for so long over such a simple but vital transport project.
    I guess the “problem” is that it’s not a road, so it doesn’t get the funding priority that road-schemes so often seem to enjoy.

  2. For want of $50m! Shows how mode biased our transport investment institutions, processes, and politics are.

    Assessing land transport investment decisions on a value basis not a mode one is seriously overdue.

    1. No cost benefit analysis huh?

      What sort of criteria are you proposing? A “Patrick Reynolds test” where we push money into transport modes approved by Patrick Reynolds!!

      1. No like the CRL where you are made to compare dozens of alternatives first before moving onto a shortlist which gets compared, rather atm with roads which only get compared against other road alignments never alternatives, for example ask why NZTA has never compared a rail only option for AWHC or even Bus only option when they did the prelim work the assumption was always road, is that best practice?

        A system like CRL where all cost changes are heavily scrutinized unlike roading projects which can go from 600-800m to 1.8b, again ask is that best practice?

        1. It depends what you’re trying to achieve with regards to whether an appropriate comparison can be made between different modes. Clearly with the number of different modes availanle in/near the central city the CRL was always going to subject to more rigorous analysis than say the Huntly bypass where no other mode can do the same job.

        2. +1, non-road alternatives were considered for WEx but discarded very early in the piece because they simply didn’t fit. This should be far less the case for urban projects. The WEx business cases are used as examples but unfortunately people seem to be using the results and not the process as the example.

        1. The one rebuilt at huge cost to provide a new lane towards St Luke’s that now appears to be permanently coned off you mean?

        1. That depends on where those 300 trucks are going to, if they are going from POA to their delivery points within Auckland there will still be 300 trucks on the road just going to and from Wiri instead of the port.

        2. Yes, but the local delivery part is going to happen anyway, whether the line haul is by road or rail. Unless of course, businesses producing significant freight flows are once again encouraged to connect directly to the rail network via private sidings, as used to be commonplace.

    2. Who said no CBA? I am very keen on CBAs. The Third Main at $50m is sure to wipe the floor of East West at $1.85B, which after all has had no CBA since one that had the cost at $600m and only just scraped above one….

  3. Remember $1.85b+ on the suboptimal and place-ruining East-West highway, justified by the need to move road freight from rail depots, but not even $50m so the freight can actually reach those spots efficiently by rail…

    This is a broken and twisted system. Who will reform it?

  4. Correct me if I am wrong, but is this just the Manukau – Middlemore and Otahuhu – junction of the Southern and Eastern lines section? Ideally we will want three tracks from Newmarket to Papakura and maybe the eastern line to the port (which may cost 10 times more)

    1. Initially yes, as that’s the bit that has the highest frequencies of passenger services conflicting with freight services. However, there are long term plans for it to run from the Port via the Eastern line as far as Pukekohe. This would allow services from the Waikato to run express through Auckland, which in my opinion would be a minimum for these services to be viable.

      Not sure whether there is much value from a third track between Westfield Jnc and Newmarket on the Southern line.

    2. Yes between Westfield-Wiri, this is the most important section to do as both the Eastern/Southern lines share the tracks with freight traffic, the other sections are not P1 because just one line so only 6tphpd rather than 12tphpd the freight has to share with.

      A full third main between Westfield & POA will likely not be needed passenger trains move quick through this section & a large portion of the freight is coming in/out Westfield/Onehunga/Wiri rather than POA, 1 or 2 passing loops always would help though.

      Unlikely we would need three tracks to Newmarket as freight uses NIMT & likely any potential expresses/intercity services as well.

      Finishing the third main between Wiri-Papakura was estimated in ATAP at 144.8m

      1. It is partially complete between Homai and Puhinui, but with some gaps. Between Wiri and Puhinui it uses the track currently used as the headshunt from the depot.

        Filling the gaps here is relatively simple as there is no major construction required.

        North of Puhinui there is a steep cutting that will require some expensive engineering and probably a small track slew. One past that there is some civil engineering required up to Middlemore where some rebuild of the station is required. Once that is done the new line links into the existing new freight main to Otahuhu.

        From Otahuhu junction it is a relatively simple job to lay track to Westfield junction.

        A lot of the cost will be in new crossovers and the signalling.

    3. Good point Nicholas. Information circulating (verbally, I suppose call it good rumour) that the third main will actually be constructed between the junction at Westfield between the NIMT & NAL. This will allow MP trains to run into the Southdown CT site without becoming a conflicting train movement with metro services, and also maintaining separation with yard operations at Westfield.

      The only works that are likely to take place now, or long term are the third main from southdown to south end of Wiri(just north of Puhinui).

      My crystal ball tells me, watch this space after the closure of the platform at Westfield.

  5. Thanks for this Harriet. I thought the 3rd main and its funding was a KR issue.
    Whats it got to do with NZTA? An agency that has lttle interest in rail, comes up with pathetic bus solutions were HR is the obvious answer and wants to only spend billions on roads.
    I noticed today the NZTA logo on the AT emus, why? The emus had nothing to do with NZTA,
    Should there not be in its place ‘Property Auckland Ratepayers’

    1. It was in ATAP so it is considered more than just a KiwiRail issue now.

      I think it is unfair to make NZTA as the bad guys, like all agencies have good/bad people and especially before Bridges was a lot of enabling of the bad. With the hiring of Fergus as CEO we are already seeing changes, as well as a restructure that will change the culture.

  6. Business Case 101
    What’s the business need? User requirement
    “To move X people (or X tonnes) from A to B in Y time”

    Option Zero: can the existing infrastructure do this? (always have an option zero)

    Then identify the best solution to move X from A to B in Y.

    1. Business case 102. Setting a hard target like that up front is actually a really bad way to do a business case, and it often presupposes an outcome.

      For example if I you say the business is to move 5,000 tonne in five hours, and the outcome costs you $100 million. But there is another option that moves 4,500 tonne in five hours, and costs only $5 million.

      The latter is clearly the best option and would undoubtedly have the best efficiency and cost benefit, but it doesn’t meet your requirement of 5,000 tonne, so you end up spending twenty times as much to move an extra 10%.

      I’d also suggest that outside of a soviet command economy, there is no such thing as a business need. You have an interrelated web of fixed and variable costs, market prices, production and sales targets, etc, that make up a sum of business performance. Rail and public transport is no different.

      1. If you don’t know what the goal is, you shouldn’t be spending any money on it, as you’re just solutioneering.

        You spend money on needs, not on dreams. If you can’t define the result before investing then you have absolutely no way of knowing whether it’s a success or not.

        In your case, the problem is a poorly defined goal; if 5000 tonnes in 5 hours is the requirement, then it doesnt matter how cheap the 4500 tonnes solution is – it won’t work.

        Imagine we have a river 100m wide. No matter how cheap a 99m long bridge is compared to a 100m long bridge, it won’t work.

        Now, X and Y can have some variability, but they still need to be predefined. Otherwise it’s just a bunch of fuzziness that is impossible to assess.

        1. Except that we never need to move any people or freight, it’s all want. You set a goal of 5,000 tonnes in 5 hours and several other goals, see what percentage of each you can achieve with several options and then pick one that achieves most benefits at low cost. There is also obviously some strategic considerations too; ie WEx as expressway gets trucks off SH4 and SH27 or Victoria Street as linear park improves non-car mode share to CBD reducing motorway congestion.

        2. But JDELH, the “goal” can be some nebulous concept such as “To improve the economy of Northland”, and on this basis the Holiday Highway is “justified”. In reality this is spending money on dreams, defining the result before investing, with no way of knowing whether it will achieve the nebulous goal or not. The dream is Steven Joyce’s, and it is simply to have a shiny new motorway over this small bit of the route. Benefit-cost ratio be damned!

          He has done the same thing down on the Kapiti Coast with the near-complete “Expressway”, where the $800m cost (or whatever it has inflated to now) dwarfs the price-tag of the perfectly adequate “Sandhills Route” scheme that the local council had approved and would have been finished by now, but for Steven Joyce and his dreams. Now the farce is being repeated with Transmission Gully, BCR=0.1->0.6 depending on who you listen to (or a magical 1.4 if you believe NZTA – and sensibly the board of inquiry didn’t believe them over the Basin Flyover farce). It’s as you say – “just solutioneering”, “just a bunch of fuzziness that is impossible to assess”.

        3. “the “goal” can be some nebulous concept such as “To improve the economy of Northland”, and on this basis the Holiday Highway is “justified””

          Except the business case for the Holiday Highway is silent on the improvements to the economy of Northland. That’s only ever been a political justification. Given Albany to Puhoi motorway shaved 17mins off the trip further north and Northland hasn’t really grown in any exceptional way after the opening of this bypass I doubt there is any economic justification possible.

        4. Not sure of that particular business case but the goals were probably something like:

          Reduce deaths and serious injuries by 80% on this corridor.
          Reduce travel time from Johnstones hill Tunnels to Dome Valley by 5 minutes.
          Reduce travel time variability from Johnstones hill Tunnels to Dome Valley in evening/morning peak by 5 minutes and holiday weekend peak by 7 minutes.

          It will achieve those goals, but uses a lot of money to achieve 100% of them.

        5. Again, that is really terrible way to specify a business case evaluation.

          Certainly a 99m bridge will do fine, if you extend the abutment by 1m. Or you could do a 40m bridge, if you build half a kilometre more road to a better location. Or maybe a tunnel is cheaper, or a ferry punt… but if you specify “build a 100m bridge”, you are picking the outcome. You should set flexible goals instead, like “find the best way to cross this river”. That is far from impossible to asses, that is in fact the whole point. Compare all the feasible options in terms of a range of factors, construction cost, ongoing costs, benefits, social impacts, environmental impacts… to find the optimal solution. Indeed, in some cases the optimal solution is to do noting, or even to remove or close something. Again if you pre-decide what it must be, then you’ll get exactly what you ask for.

          FYI, there is no such thing as need in transport, planning or infrastructure. A ‘need’ is just want or desire you place a lot of value on.

        6. Precisely, that’s just something they want. But if you specify a four lane semi-motorway link as the “need”, then that is what you get. If you specify the goal as something like “improving freight capacity and reliability times while not paving over the harbour edge” you might get a different outcome 😉

        7. You’re right, I confused a technical requirement and a user requirement

          But my first point stands: unless the user requirement is clearly defined, you shouldn’t spend a single $

          I think the flaw is that we define/describe these business cases before we’ve actually identified the need, and then we frantically try to identify the benefits that will accrue.

          My analogy is this:
          1. Currently we go to Noel Leemings with $1000 and buy the best TV we can get for the money, then we say “ooh it’s 65″ and HD LED and it has this”
          2. What we NEED to do is say “I need a TV that at a viewing distance of X provides Y visual definition” (this is a user requirement that looks like a technical requirement)

          I think we’re almost in violent agreement here. Absolutely it’s about “improving freigh capacity” but it still needs to have a hard target otherwise you can’t judge whether it’s a success or not (success in terms of achieving designed goals, which is a little circular I admit)

        8. JDELH, you could take your TV analogy further with the current government’s approach to PT funding which is often ‘TVs are all well and good but in the future we are all going to be wearing VR goggles so no need to buy a TV’.

  7. They need to look at including the 3rd main before starting work on the proposed cycleway/walking track that is going across Hobson Bay. Otherwise things will have to be dug up, moved, raised, etc. similar to what happened at Halsey Street.

Leave a Reply

Your email address will not be published. Required fields are marked *