Earlier this year I put in an OIA to KiwiRail asking some questions regarding the Auckland Rail Network, however, due to the abundance of transport news I have not been able to post about it.

One of the items that came back to me was preliminary designs for what a Westfield Flying Junction would look like as KiwiRail needed to do one so the NZTA could make sure that any East-West Link design did not preclude its possible future construction. For those unfamiliar with the terminology, a flying junction is a grade-separated junction allowing faster/more efficient movement of trains as they do not need to wait for the opposing train to clear before they can cross.

Westfield Flying Junction (For better res click the link above)

The design looks seriously smart not only separating the conflicting movements between the Eastern and Southern Lines but also allowing easy freight access to/from both Metroport and Westfield yards. It looks as if the Southern Line is elevated over the top using an embankment and small overbridge while the Eastern Line Citybound track skirts around and sneaks under. The design is also really smart as the third main does the same allowing freight trains heading on the Eastern Line to do so without crossing the Southern at grade.

It also looks like it connects well with the future 4th main and proposed interim 3rd track towards Sylvia Park to give stacking capacity which could be turned into a third main to the Port (A third main to the Port is in Upper North Island Freight Story as well as the last Integrated Transport Programme but not in the more recent ATAP as KiwiRail did not consider full triple tracking was necessary within the timeframe)

All in all looks like a really great design what do you think?

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43 comments

  1. Building that scale of bridge in New Zealand’s busiest live rail track environment will be a construction nightmare.

    Amazing to pull it off, sure, but the block-of-lines to do it will be big and will affect everyone who uses a train in that intersection.

    1. Its not all bridge only a small section is I believe its mainly embankment with the bridge only the section where those tracks sneak under.

    2. KR does a _lot_ of night work, so I can’t imagine that building this would be that tough.

      Besides, the spans will be prefab. Just need to excavate, pile, construct and poor over a few nights.

      Don’t know when the last train leaves, however I’d suggest around midnight: http://www.kiwirailfreight.co.nz/freight-schedule.aspx

      Of course, they’ll probably just schedule it for a regular Block of Line. Usually the BoL is Easter and Christmas.

      1. Hopefully the BOLs will largely be gone by the time this is built. The rail network is becoming an increasingly important part of the PT network and we can’t just keep assuming Christmas/New Year and Easter are times we can just shut the rail network down because most of the commuters are on holiday.

    3. I agree that is an issue but there are solutions. Increasingly in Australia this sort of work is being done with a large proportion of pre cast structural components that are lifted into place with a big crane. Even bridge head stocks and piers are possible. This allows minimal time of rail closure and ensures good quality because you can test the components in the precasting yard.

    1. They didn’t say but I don’t think it will be to bad the reason is it is mainly embankment rather than bridge structure.

    2. These days all grade separation projects are $50 to $100 million per junction in an urban area. Rail can cost more, due to the longer ramps needed because of the flatte grades trains require. So $100-150 million? We can really only guess till somebody draws a plan and gets survey and we can see what property and services need to be shifted out of the way.

  2. Maybe I misinterpreted the diagram, but it looks like all southern line trains will end up on the western 2 tracks and all the eastern line trains on the eastern 2 tracks –

    meaning that the southbound southern-line trains and northbound eastern-line trains will have to cross over multiple tracks before the junction, which kind of defeats the point of the flying junction?

    I would have thought it would be more like the flying junction near wellington railway station.

      1. Right, I see what you mean, I thought the main eastern-line tracks were the thick lines that stay along the bottom on the diagram.

          1. Hi Harriet,
            Are you sure? I would like to see the platform arrangement at Otahuhu with this new layout, because it looks like the Southern and Eastern lines will be on different platforms. Otahuhu should have a northbound services platform and a southbound services platform, otherwise you are halving the frequency for most passengers.

          2. I’d be very surprised if there are southern and eastern line tracks between Westfield and Wiri. I think it is more likely there would be all stops tracks and express tracks, especially with Regional Rapid Rail.

  3. Now that East West Link is unlikely, if this goes ahead can we include a cycleway along the rail line to close the gap between the foreshore cycleway and AMETI / Sylvia Park?

  4. I’m not certain that the “Eastern Line Citybound track” referred to above, which “skirts around and sneaks under”, is actually a main passenger line.

    The lines which pass under the proposed bridge are all drawn as ‘thin’ on the plan and consist of freight connections from Westfield and Southdown yards to the Eastern Line, plus this skirting-around ‘fly-under’ line.

    The actual main lines (thickly-drawn) come together side-by-side somewhere near the old Westfield Station site, but are connected only by at-grade crossovers.

    If the aim here is to separate out the Eastern and Southern routes without them needing to cross each other then this presupposes a 3rd and 4th passenger main all the way to Wiri. Whether or which passenger services are planned to use the fly-under line is hard to know.

    1. Dave the northbound Eastern Line trains go under the new NAL overbridge, you can see it peel off at the east of the image and pass under as a double.
      Also freighters can bypass both the junction and the new bridge to the west, connected to the NIMT and the yards.
      PoAL freighters can also separate from Metro trains on Third on the eastern line, and PoT ones to west (already the case to a degree)

      let do this!

      Also I would love to have all AKL port-Wiri traffic hauled by electric locos. The wires are there.

      1. Well now that KR needs to find a solution to keep using electrics on the NIMT, I imagine that having locos compatible with the AK network becomes a much more viable option,

      2. Yes, I see that Patrick. But that “Eastern Line. . .under the new NAL overbridge” does not look like a main line alignment to me. It looks more like a 25Km/h yard road, not intended for regular passenger use.

        But. . . I could be wrong.

        1. I was able to drop the pdf straight into my CAD system and get a radius for that curve: 250m which, according to the national rail standards allows a maximum speed of 55 km/h (211 m to 250 m radius) or 60 km/h (251 m to 300 m radius). Should be easy enough to increase the radius slightly by using a retaining wall and tucking it in closer to the tracks it passes under. Speed is going to be limited, however, by the preceding diverging turnout which appears to be a “high speed” type but that is a relative term.

          1. Thanks MFD. So that link *could* be used as a main line.
            But my query is, is that the intention? Or is the scheme predicated on separating the Eastern and Southern lines with no plan for an intensively-used crossing of the main lines at this point?

          2. In essence it really is a basic flying junction; the northbound eastern and northbound southern are one track south of the junction, as are the southbound tracks.

            There is a left-hand 1:18 turnout where the northbound eastern deviates from the northbound southern and then goes under it. That turnout effectively determines the maximum speed for a northbound eastern line train through the junction so efforts to increase the radius of the curve would be unwarranted.

  5. Good idea which seems to completely forget about the sensitive Anne’s Creek environs. The EWL project took great pains to minimise effects here. The same level of care appears to be absent in this proposal for a (cheap) embankment through part of it. Allowing for settlement and ongoing readjustment of level throughout its service life will add cost. Bridge anybody?

  6. Well now that the Labour government has (thankfully) put a bullet between the eyes of the EW link, and discovered EY’s buried report demonstrating the benefits of rail, then perhaps we can design something with for the public good.

  7. Thank you for posting this Harriet. Certainly needed to sort out the delays between Westfield and Wiri. But why so secret? All that resource consent for the EW link and this construction just simply under the radar.

  8. In essence this junction, more really than the Newmarket one, is the third corner of the CRL triangle. CRL will deliver a flying junction at Mt Eden, where the Western and Southern patterns interline, and this is the equivalent where the Eastern and Southern meet.

    As the post CRL pattern reduces the Parnell line to secondary status by routing Southern services via Grafton and Western ones direct to Britomart, this is really the most critical point on the Metro network. Both Newmarket and the eastern Britomart junctions are secondary, though separating the Britomart junction would add resilience too.

    And that’s not even considering freight traffic, which is important and growing here.

    Do it now.

    1. Would love to some analysis of the efficiency gains this would deliver for both freight and passenger services. Along with the 3rd and 4th mains it would certainly take any excuse for padding out of the Metro timetables, freeing up trains, cutting travel times, lifting reliability. Cutting operating costs.

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