With the new Government and its new transport focuses including “mode neutrality in freight transport planning” I thought this would be a fantastic opportunity to write about something we have been thinking about for a while. While planning bypasses and re-alignments of old routes for expressways or new state highways is often discussed and often also funded very little discussion happens around whether we could do the same on the national rail network.

In Regional Rapid Rail we suggested two possible deviations

  1. The Whangamarino Deviation creating a new straighter double track section on better ground around Meremere and Te Kauwhata while leaving the existing single track section as a passing loop.

    Whangamarino Deviation
  2. The Bombay Deviation creating an express bypass of the circuitous existing route via Pukekohe and this 17km route avoids the 31km long route via Pukekohe, a saving of 14km and would be much faster potentially saving around 20min. This would also make triple tracking to Pukekohe redundant.
    Bombay Deviation (Red = Tunnel, Green = Surface, Black = Existing)

    Apart from the obvious speed benefits in combination with the planned third and fourth mains in suburban south Auckland, and the proposed Whangamarino swamp deviation of Stage 2, the Bombay deviation would effectively provide three or four tracks on the NIMT for over half of the route between Auckland and Hamilton allowing both increased freight and passenger capacity.

But we also considered one other deviation but did not include it in Regional Rapid Rail in the end due to scope which we called the Ohinewai – Morrinsville Rail Deviation.

Ohinewai – Morrinsville Rail Deviation (Red = New, Black = Existing)

This new 39km deviation across very low populated and flat ground would be 30km shorter than the current 69km route. It also doesn’t travel through the Hamilton urban area and would be built with relatively straight geometry allowing much faster speeds drastically cutting down travel times for freight between Auckland and Tauranga potentially creating a step change in freight speeds as well as capacity especially if combined with the Whangamarino and Bombay Deviation.

The main benefit of this line would be for freight as you wouldn’t really want to split the services giving lower frequency between Hamilton and Tauranga but you could run a few peak expresses using this route in the future which would only take around 17min to run this section allowing sub 2hr travel times between Auckland and Tauranga. Even if not used it would however still large benefits to Regional Rapid Rail as Auckland – Bay of Plenty freight trains would no longer use what could in the future be a highly congested central Hamilton section.

This would also benefit road users as well as New Zealand as a whole. The recent EY Report showed the large enviromental, safety, maintenance and congestion benefits of rail which was written about in more detail by Matt here.

With the 1b a year Regional Development Fund with one of its major purposes being Regional Rail as well as the Governments desire for mode neutrality in freight transport planning these type of solutions should definitely be looked at, or at the very minimum funding given to KiwiRail to scope then designate and protect these corridors so we can use them in the future. Too many times have we failed to protect corridors resulting in large cost inflation usually resulting in the project not happening.

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70 comments

  1. Seems like a no-brainier to me, just like now we should get a proper plan in place to remove all rail crossings in Auckland over say the next 10 years.

  2. Should qualify as a Railway of National Significance.

    “Show me the money?”

    Election-promises by National were for more Roads of National Significance to the tune of $10bn

    Now that National and their more-RoNS have gone, this money, wherever it was supposed to come from. can be re-directed to projects like this.

  3. We’ve justified reams of RoNS based on small travel time savings both for people/cars and for trucks carrying freight (a lot of that freight however seems to mostly time insensitive freight which doesn’t really need it).

    So what would be the maximum projected time saving benefits for both people and freight if all the improvements proposed here were put in place?

    Then can’t we use that to “sell” each section as we do it as working towards letting us complete the whole?
    Just like how motorways are done.

    I don’t know whether this should take precedence over improving Northport to Auckland rail links.

    Of course if these were motorway projects we’d do both immediately to gold standard, ‘cos you know Government can’t “pick winners and losers” in the ports or regions.
    They might get it wrong and that’s historically “a bad thing”…

    My thoughts are without a proper regional ports strategy we’re in danger of prioritising the track building for the wrong sorts of traffic

    Who is to say if in 10 or 15 years time, population growth and density means moving people quickly and with minimal delays along this route becomes its most important function.

    So if we treat it like a freight only corridor improvement we’d likely sell ourselves short, so I think we have to make sure it can work well for both people and freight, which means to my mind a high speed capable track (or tracks), not a single line replica of what we already have.

    So maybe bore two tunnels side by side and make them wide enough to allow us to double track both bores.
    Like Waterview in a smaller form.

  4. I think the realignment to concentrate on – and the one most likely to get any buy-in within the current term of this government – is to realign the northern rail line around the Brynderwyns essentially parallel with the SH1 rebuild, to take the rail straight to Northport rather than through the convoluted and time-wasting route that links to the Dargaville branch line.

    I would do it using the NZTA SH1 corridor designation required for the new SH1 alignment.

    If I ruled the world 🙂

  5. Interesting ideas. A deviation was previously proposed from Pokeno to Paeroa back in the 1940’s to bypass the stretch of line in question. At this time Paeroa was on the railway line to Tauranga before the Kaimai tunnel was built.

    I understand that it deviated from just north of Mercer and that a large amount of earthworks were constructed before the project was abandoned. Some of the alignment now forms part of SH2 and McIntyre Road and is clearly visible on google maps.

    Perhaps elements of this previous deviation could be reused for a new one.

  6. That depends if the track will be use for passengers, or fully freight only with no intention to convert into commuter rail.

    It would be more desirable to have passenger rail go though town centre to act a catalyst for urban development.

  7. My thinking is that Shane Jones & Co have factored in the Northland Rail upgrade.
    That is fixing existing tracks and not building new tracks.
    I also note that the announcement about the new Antipodean Explorer Luxury train service has factored in a possible rail visit to the Bay of Islands…..so someone knows the future plans for Kiwi Rail.

      1. Rail never quite reached Queenstown. The traveller in past times would have taken the branch line from Gore via Lumsden to Kingston at the south end of Lake Wakatipu and then caught a steamer such as the TSS Earnslaw along the lake to Queenstown Wharf.

        There was also the line from Dunedin to Cromwell which ended about the same distance from Queenstown but then there would still have been a road trip to complete the journey.

        1. The media release was luxury rail travel to Queenstown. Nothing was said about coach travel in any part of that journey. Whilst the concept is good, logistically would be a nightmare. Kiwirail will charge high track and ‘Hook & Tow’ fees and will make sure that their freight and passenger services will have priority. Those poor passenger being delayed due to heat restriction through the central North Island and on the Canterbury Plains.

  8. Too much overlap with the NIMT, Taupiri-Motumaoho will give bigger bang for buck, utilising the existing double track line to a greater degree. It really needs to link in with a decision over Auckland’s port. If Tauranga is to take over as Auckland’s primary port, then this can be justified.

    Taihape-Hihitahi, Kakahi-Rata, and Otaki-Manakau have all been on KiwiRail’s wishlist since 2008. Ontrack was planning them, but all three projects were sunk after the 2008 election, along with Marsden Point.

    The second track alignment through the Whangamarino swamp is already built. It just doesn’t have any track on it, because after completing the formation, WWII saw a steel shortage preventing rail manufacture, and they never went back and finished it.

    1. Well when they say Morrinsville on here they actually mean Motumaoho, but since most people don’t know where that is lets go with Morrinsville.

      Looking at the image the new line will cross Piako road near Matuku road to merge into the existing line just before it crosses State Highway 26. I am a bit worried about the number of railway crossings that will result in such a small area. The intersection of SH26 and Piako road is already a bit of a mess ignoring the rail line. Add in the increasing train movements, a new junction right next to a road and the fact that at some point in the future the line will have to be electrified and I can’t help but think that something will have to be done about grade separation in this area.

      1. If building a new line from scratch in a rural area it wouldn’t be hard or expensive to lower the roads and slightly elevate sections of the track when being constructed. Rail of course is best over the top due to the height of OLE if and when that is added.

    2. Kakahi to Rata is about 180km and includes Taihape to Hihitahi, that would be a huge project, might stay on wishlist I think.

    3. Re Otaki-Manakau rail. The current line immediately north of Otaki is being moved as part of the Otaki-Pekapeka expressway. Is this different from the earlier proposal?

      1. Yes, very different. Earlier proposals were to ease the various sharp curves around Forest Lakes, speeding up the whole Otaki-Manakau section.

        The Otaki-Pekapeka expressway project merely realigns one rail curve at Otaki. The small benefit to rail is an incidental spin-off from the roading project and not part of any wider plan to improve rail.

    4. Could be Geoff. I guess it comes down to the trade off between a 35km of entirely new line, or 16km of old and 25km of new line to cover the same distance.

      I.e. is better to build an additional 10km of new straight alignment to avoid 16km of older, windier alignment through Huntly and Taupiri.

      For rapid rail, 10km @ 150km/h vs. 16km @ 80km/h is fairly significant, its eight or nine minutes difference. But is that difference worth the cost of building 10km more of new line? Probably depends on just how cheap or expensive it is to actually build new train lines across open ground.

      1. Nick, your Ohinewai route would be about 35km, vs Taupiri at about 38km, so not a lot different. Your route would require a tunnel to get through the hills east of Ohinewai, or at least a lot of earthworks. It’s not flat. The existing line through Huntly would still be needed, but would be less viable, as would the overlap portion of your proposed new section that overlaps it. Maximising usage of existing infrastructure whilst deviating only the section that offers a very clear benefit is the way to go. The section of existing line that changes direction in a manner where a deviation becomes useful is clearly at Taupiri, and that option would likely stand out significantly ahead of other options in any business case.

        If you’re keen to see this line proceed further, would GA be interested in meeting with other potential stakeholders such as Port of Tauranga?

        1. Geoff do you Know if KR asked NZTA to include accommodate this route in the Waikato Expressway work currently underway? As Taupri-Morrinsiville is crossed by this autobahn…And if NZTA have included a suitable underpass…?

  9. Its too hard to tell from the maps but, it would be awesome if the realignment covered the dragstrip at meremere and the motorsport park at hampton downs. Having easy non-road rapid access to these places would be awesome for motorsport fans who are constantly stuck with the age old problems of getting to these popular venues.

    1. This comment has had me chuckling (plenty of other pursuits that would benefit from rail access too) but actually it would make a lot of sense. I’ve had friends who like to watch the motorsports at Western Springs describe the natural inclination to speed in their cars afterwards, and I think anything to keep them out of their cars until the next day would be good.

  10. I recently drove between Auckland and Tauranga and I was suprised and even appalled to find a fleet of skeletal trailers carting empty containers between the two centers both ways. You would wonder why, someone needs to do some work on their spreadsheets.
    Anyway its a bit like when you see full logging trucks going in opposite directions but at least all logs aren’t the same but containers can’t work that out. And surely they could be put on the rail or perhaps there is a capacity issue. One thing I thought of is for Kiwirail to copy the trucks and have lightweight wagons especially for the job that should lower costs if that is the problem. Carting empty containers must be a mind boggling boring job especially when we are told there is a shortage of drivers. But anyway maybe you believe there will be a fleet of self driving trucks delivering empty containers around any time now but I don’t.
    But the deviation really depends mostly on what happens with the ports unless Kiwirail can dramatically find large volumes of other traffic that the can transport on the route. My observation is that all of the sidings in Auckland are pretty full up with wagons moving down the main trunk. If large amounts of extra freight is going to move between Tauranga and Auckland or to Northland for that matter extra sidings will be required to handle it.

    1. Of course, the Greater Auckland engineering and design team, in combination with the our operations specialists, economists and procurement staff, prepare cost benefit analysis for every suggestion made on blog posts.

        1. Jon we put out twelve blog posts a week, every week. Obviously with this level of advocacy we have to save the detailed work for our larger campaigns such as the Congestion Free Network and Regional Rapid Rail, particularly now the government is adoption our proposals and asking for our advice on regional transport development. None of us get paid for this and we all work day jobs.

          As for you, you’ve spent the last five years arguing obsessively for one idea that three separate business cases have shown to be, at best, a waste of ratepayers money. So indeed, if you are going to continue to stake your reputation on a single issue everyone else have moved on from, then yes you need to come to the party with something pretty compelling to show why you think every other assessment of the facts is wrong. If you want to convince the government to spend money on something their own reviews have shown to be poor value for money, the you’ll need a pretty damned solid business case!

  11. Retaining Avondale – Southdown corridor for the future benefit of the North Auckland Rail line upgrade and Marsden Point line is the most pressing issue. It will mean increased freight trains will bypass the heavily congested Mt Albert – Newmarket – Westfield section.

    1. I wonder if the LRT tracks actually prevent a track being laid though? I would have thought that the corridor was more than wide enough for both.

      1. The corridor is 30m wide or more on the shared section, and the design for LRT leaves space for a full Avondale-Southdown designation to remain, as per Kiwirail’s requirements. So not an issue in the slightest.

        Sounds like Jon is poorly informed.

        1. This is the first time I have seen anyone say that there is space in the alignment for both LR and HR. If this is indeed the case then that removes 1 major issue I had with LR.

          1. I don’t see why anyone would say there wasn’t to be honest. It only takes a quick look at google maps or the councils free online GIS viewer to check this. The strategic transport corridor zone in the unitary plan shows the extent of it.

          1. Mostly NZTA (the motorway corridor is quite a bit wider than the actual motorway), with Kiwirail alongside that. The areas where local roads and streets cross or intersect is owned by AT.

          2. Ok, so we can deduct from your comments that AT own very little of the Avondale – Southdown railway corridor and most is owned by Kiwirail ( I’m not worried about NZTA land for the motorway). What value did AT put on their dubious LRT Airport Tram costings to acquire the land or at least 1/2 of it from Kiwirail?

          3. Surely LR would be built on the motorway designation, it’s unlikely to ever be widened given waterview puts a hard constraint on the width of the South-western motorway.

          4. Jon Reeves, how can you claim the costings are dubious in the same breath as admitting you have no idea what was costed and at what rate, and where. All you’re doing here is showing you are out of the loop and have zero idea what is actually going on.

  12. Well this is arrant nonsense… in terms of network and capacity planning this is kids drawing with crayons on the kitchen wall…

    Why? Two reasons:

    1 The network constraint for rail in the Akl-Tga circuit is the Kaimai tunnel. Not only does the existing tunnel have water problems and is single track to get the best out of the network and relive the constraints the next development should be the double tracking between Hamilton and Tauranga and new tunnels through the Kaimais.

    The author seems to forget that Hamilton is a major freight network point (that’s why its called the Golden Triangle!!) so cutting it from the circuit makes no sense… there is no value in cutting across the Morrinsville without getting the Kaimai tunnels sorted.

    The train capacity constraint is the tunnels.

    2 Why bore through the Bombays? There seems to be around 4km of tunnels required, which would shorten the route, but cost vast sums… Based on the Waterview tunnel the cost would seem to be around $500m per km, which is $2 billion – to save 20 minutes on a non-congested network. And it would have to be dual tracked (two tunnels as per Waterview) and would require enough height to accommodate future transport growth… so incl inflation it would seem reasonable stab at an estimate

    Sure it might be faster and straighter, but I cannot see for the life of me why a freight train would benefit from a saving of 20 minutes.

    Instead of drawing with crayons think about the use case and the cost of installing the infrastructure… and the payback period… $2 billion sure build a lot of houses… for examples…

    1. Ha, complains of kids and crayons then immediately lays in with the reckons.

      1) There is a lot of freight that runs directly from Tauranga to Auckland without stopping in Hamilton. Likewise for future passenger operations, there will be strong demand for direct routes between Auckland and Tauranga (and Rotorua). And no one is proposing to remove the tracks through Hamilton for the services that do need to go there.

      The Kaimai tunnel can, with the right upgrades either side, accommodate four trains an hour. That’s almost 100 trains a day to the Bay of Plenty. The bigger constraint will be in south Auckland. If we would have to triple the number of trains running through the Kaimai before we get to real capacity issues.

      2) The Bombay tunnel avoids the need to quad track the line through Pukekohe, which is the current long term plan. It may not be totally congested now, but it will be once the line is electrified and suburban services start running at high frequency. That’s why the call it planning. The combination of not needing to quad track, having two routes of resilience, plus a much shorter faster route with 20+ minute saving for express freight and passenger services makes it a captivating proposition.

      A rail tunnel will be vastly cheaper than a motorway tunnel per km, in the order of one quarter or one fifth the cost, or perhaps $500m in total for a 4 to 5 km link.

      The former is a single narrow bore (even for two tracks and clearance for double stack) and electric, the latter is *two* enormous bores (for three lanes each) with cross passages, ventilation and fire control systems from hell. Not to mention the elaborate interchanges either side, of which the rail needs none.

      1. You can’t double stack on the current narrow gauge track. So you either have to move to a wide gauge or not at all… so my cost estimate may be on the high side, but you can’t claim the numbers are bad until the true calcs are done.

        As MFD states below the current calcs are not going to work for freight, so that does imply a longer tunnel and thus a higher cost…

        Not saying I am right, but the key point is why this upgrade? It makes no sense on a stand alone basis

        1. It’s from the Regional Rapid Rail proposal, aimed at allowing rapid passenger trains to bypass freight on the existing long and slow alignment via Pukekohe.

          If you think freight can’t run in it then so be it, freight stays on the existing line and the deviation is for passengers only.

    2. “2 Why bore through the Bombays? There seems to be around 4km of tunnels required, which would shorten the route, but cost vast sums… Based on the Waterview tunnel the cost would seem to be around $500m per km, which is $2 billion – to save 20 minutes on a non-congested network. And it would have to be dual tracked (two tunnels as per Waterview) and would require enough height to accommodate future transport growth… so incl inflation it would seem reasonable stab at an estimate”

      This point is comically bad. Basing costs on a tunnel cross section that is about 10 times larger is a bad start.

      I’m also not quite sure how you can argue that the Hamilton to Auckland route is non-congested! It’s packed with trains and we need to quad track right to Pukekohe in the medium term. The passenger network is also incredibly congested, saving 20 minutes on a train trip relieves congestion on roads.

        1. Looking at passengers. If the average occupancy on RRR trains was 100 and the value of time for each passenger was $8 and hour (conservative), the passenger benefits are over $200m. The freight would be much higher, and there are safety benefits from taking all those trains off of level crossings on the existing track. There are also massive traction power, maintenance, and rolling stock savings from the shorter trip and more consistent speeds.

  13. “The freight would be much higher”

    As presented in the RRR the Bombay tunnel bypass with a 6km tunnel and 1.7% gradients is unsuitable for freight. In order to maintain a 100 km/h speed (the practical limit for the current freight rolling stock) a freight with two DL class locomotives could haul a maximum of around 7 fully-loaded container wagons. That’s very poor productivity. A more typical 2000 tonne train with two DLs would be limited to around 38 km/h ie. totally unsuited to mixing with 160 km/h passenger trains. Note that the RRR scope of work does not include electrification in spite of suggesting that freight would be electrically hauled.

    Happy to share the calculations and happy to share my engineering critique of RRR (already written) but Mr Skarrat has created a dense fog of incomprehension over the comments section of the original RRR posting.

    1. MFD, I would like to read your engineering critique of RRR, url please?
      Agree that the Mr Skarrat dense fog obfuscates the RRR post and comments, at a recent political party meeting I attended one commentator remarked on the great work GA does with RRR but sighed on how one nonsense troller rubbished the whole article.

    2. Actually it’s a 2% grade that we designed it to, 1:50. Are you sure that gradient is unsuitable for freight?

      The RRR does actually say the tunnel would be electric only (i.e. wires as far south as Pokeno at least), and that the new passenger fleet would be dual mode. This does therefore assume that any freight using the tunnel would also have a dual mode locomotive, or would require a change of loco at Pokeno.

      However, considering that was a plan for the year 2047, I think we can assume that if we are at the point of building a Bombay deviation we’ve already electrified from Auckland to Hamilton.

      There was never any suggestion that DLs would ever run in the express tunnel (will they even still be running in the 2040s?), any remaining diesels would continue to use the existing line while the new tunnel would be limited to higher speed passenger trains and express freight (i.e. electric traction capable of 110km/h or so).

      Please do share your critique, in fact send it through the the Contact Us and we can run it as a guest post.

      1. “Actually it’s a 2% grade that we designed it to, 1:50. Are you sure that gradient is unsuitable for freight?”

        A combination of deep cut and fill on the approaches can reduce that to around 1.7%. There’s a cost associated with that that would need to be compared to the benefit That’s still severe for a freight line that is intended to be high speed. 2% is slightly more than the Raurimu spiral but is accepted that typical freights are slow up that grade. On the Auckland-Tauranga route that grade would become the ruling grade and for a given locomotive or combination thereof would determine the maximum train weight.

        I plugged a 2% grade into my spreadsheet and set the speed at 110 km/h. A short train of 1000 tonnes (around 14 fully-loaded container wagons for example) would require a locomotive power of around 10.5 MW. To put that into context an EF locomotive is rated at 3 MW. Note that running freights at more than 100 km/h is going to require a different bogie design (ie. more expensive) fitted to the wagons. The bottom line is that moving freight trains at 110 km/h up a 1.7% or 2% grade is extreme.

        “This does therefore assume that any freight using the tunnel would also have a dual mode locomotive, or would require a change of loco at Pokeno.”

        In this context a dual mode locomotive is a canard; no suitable locomotives are available within the loading gauge and axle load limits and the excessive power required for this short section effectively requires a locomotive change or (more likely) electric bankers with the associated cost and time penalty.

        “However, considering that was a plan for the year 2047, I think we can assume that if we are at the point of building a Bombay deviation we’ve already electrified from Auckland to Hamilton.”

        That wasn’t costed in the report. One could also assume that electrification from Hamilton to Tauranga is also in situ by that date…and the rest of the NIMT as well, in which case the dual mode EMUs would largely not be required…but identifying and quantifying the benefits without doing likewise with the disbenefits suggests a modicum of confirmation bias.

        “There was never any suggestion that DLs would ever run in the express tunnel”

        Quite right, too. I used that as a recognisable benchmark of power output.

        “Please do share your critique, in fact send it through the the Contact Us and we can run it as a guest post”.

        Will do (but off on a 2 week holiday on Friday). It is phrased as a (long) comment to the original article so I will need to rework it for a freestanding article and prepare some graphics and references. I may need to check with you on some of the underlying assumptions rather than assume what I think that you have assumed.

        1. The RRR was focussed on passenger trains with freight as an afterthought. We didn’t consider costs or benefits from freight in the tunnel at all, only noted that electric ones could use it and would probably benefit greatly. So yes we didn’t lump electrifying the rest of the NIMT and ECMT into the cost, because its not needed for the passenger trains.

          If freight trains can’t run in the tunnel, or if only a special class of wagon and locomotive can, then so be it, it doesn’t change the RRR analysis and the rest can always run around the long way.

          Our approach with the dual mode MUs is that it allows the service to get started in the first stages (Britomart etc) and expand out in the latter stages even if the main trunk lines are electrified (Rotorua and Cambridge for example). This makes staged electrification expansion all the more easier to deliver.

          I think we noted somewhere that if they did electrify the whole network then the fleet could be modified to remove the Diesel engines and fuel systems quite easily. Thats the sort of thing you might do at a mid life refit after 15 or 20 years.

        2. MFD, I believe for this to work we will need stretches of triple or quadruple track (think of these as very-long “dynamic” passing loops), where fast passenger trains can overtake slow freights.

          As you point out, 100+ Km/h freight is not really feasible, especially if the only imperative for this speed (and hence huge power requirement) is to mesh them in with passenger trains over this particular portion of the route.

          By the way, I plugged a 1100T train (1000T wagons plus 100T loco) into my spreadsheet and the power for a balancing speed of 110Km/h on a 2% grade assuming no losses or air-resistance comes to 6.6MW. Losses and air-resistance will add to this but I’m not sure how you get the total as high as 10.5MW??

          1. My calculations allowed for 25% additional power to cover aerodynamic drag, rolling resistance etc. Note that the drag at 100 km/h is 1.89 times the drag at 80 km/h and that tunnels can add considerably to that drag.

            The calculations also used a DL as the reference power unit; 108 tonnes and 2.38 MW available for traction. My estimations (with 10% allowance for drag etc) suggest that your 1000 tonne train with a single DL on a 2% grade will be sitting at around 36 km/h and if it is raining the locomotive will be close to its adhesive limit. To maintain 110 km/h it would need 5 x DLs with an all-up train weight of 1540 tonnes.

            In my view the best way to optimise freight train times, capital utilisation and maximise energy efficiency is by minimising the need to slow them down and stop them rather than running them faster for periods then putting them into loops to allow higher speed passenger trains past.

          2. It’s not the freights that go into the loops, the freights stay on the main line. It’s the high speed trains that go into the loops to pass them. We’re effectively talking about separate high speed tracks from Te Kauwhata to Drury.

          3. That’s not what the RRR report says though, Nick;

            “With both deviations, the existing main trunk line would be retained as a passing loop for slower freight trains”

            In its simplest form a passing loop generally consists of a section of track parallel and adjacent to the main line connected by means of a turnout at each end. The loop is accessed by taking the diverging (ie. curved) path through the turnout and that diverging route imposes a substantial speed limit and one of the functions of the signalling system is to indicate the limit to the driver. That limit is a function of the turnout design. For the typical 1 in 7.5 turnout used on most of the Kiwirail network that limit is 25 km/h. “High speed” turnouts are used where warranted. These have a 1 in 18 frog angle and are rated for 60 km/h.

            Given the speed penalty imposed by putting a train into a loop it is the slower or stopping train that is typically put into the loop. For a 160 km/h train to pass an 800m long 100 km/h freight (without slowing it) by taking the loop is going to require very long loops given that the faster train will be following the slower one by at least 2 km (signal block distances and time to line the turnout) then it will decelerate to, say, 60 km/h for the turnout. Once the whole train is through that turnout it will be a minimum of 3 km behind the slower train. It must then accelerate to 160 km/h to pass the slower train and get ahead of it far enough so that there is time to slow for the turnout at the end of the loop and maintain a 2 km distance ahead of the slower train as well as allowing time for lining the turnout.

            A quick and crude spreadsheet analysis suggests that, best case, it can be done with an 18 km loop. Given the uncertainties of freight train timekeeping (say 5 minutes either way) and that will add another 17 km for a total of 35 km. Is this what is being proposed for the ECML?

            In the case of the current route through Te Kauwhata being retained as a freight passing loop there is the added complexity of northbound freights having to cross the southbound high speed route twice. Flying junctions could be used at each end but one must ask why a new loop is not being provided as part of the bypass. It’s only another 4m additional width per track added.

  14. Electrifying Te Rapa to Papakura is not at all unlikely near term-ish given the new government’s sane position on climate change. Then adding the East Coast Main, to settle for the big Y of a fully electrified network, for the foreseeable: Palmy-Mt Maunganui-Akl Network.

    Cascade current diesel fleet to outside this core network. Stinky bangers become very rare indeed in AKL, Ham, Tau. Social licence to run more freight through built up areas achieved. (Port akl policy is 75%+ of growing freight task by rail).

    New electric locos, and dear old Kiwi Rail having to cope with two types of locos (depots, crews etc), contrary to their current obsession with only having one.

    1. Very important comment regarding electric freight through Auckland and other town/city areas –
      The last thing that is wanted is a vocal resident group(s) being established that live near rail lines upset at freight increases!
      I live near(ish) the rail lines and there’s a massive difference in noise and vibration caused between the passenger trains vs freight trains

    2. “Stinky bangers become very rare indeed in AKL, Ham, Tau. Social licence to run more freight through built up areas achieved.”

      …except the situations where the freight is diesel-hauled on the roads and burns 3 to 4 times the diesel per tonne-km.

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