A lot of discussion around Auckland’s rail network is focused on large and very expensive projects. Much of this is justified as the next obvious places to expand the network (the City Rail Link, Rail to the Airport, a North Shore Line and a possible Southeast Route) will bring huge benefits, but at significant financial cost. Out of the projects listed above, the City Rail Link is an obvious standout as essential for its ‘enabling’ of higher frequencies throughout the whole network – but beyond that project perhaps we need to start thinking about further low-hanging fruit to take advantage of this increased capacity.

Once the City Rail Link is completed, the latent capacity of the entire network is ‘opened up’, and the train frequency constraint of one every 10 minutes along the main lines is relieved. While, if money were no object (and theoretically it isn’t, if we can make some tough choices and not proceed with some eye-wateringly expensive motorway projects), a full Airport Loop via Onehunga, Mangere and through to Manukau is the next obvious project, there is another project that may well be worth investigating. And that is making a start on the easy part of the Avondale-Southdown Line.

The Avondale-Southdown Line is a rail corridor that has been designated for over 60 years now, originally envisaged as a freight bypass of Newmarket that has never quite gotten around to being needed. In a passenger sense, the line is a bit of an oddball – serving more the cross-town type of trip than what rail has traditionally been most popular for. The blue line below shows its approximate alignment:Importantly, because the designation is in place, both the Mt Roskill motorway extension and the proposed Waterview Connection project have had to provide for the corridor – building longer bridge spans, often doing earthworks to retain the rail corridor and other works. By the time the Waterview Connection project is completed, there will be a pretty well defined corridor between New North Road in the west and Hillsborough Road in the east, almost “ready to go” for laying tracks and putting up wires.

East of Dominion Road, the future alignment of the route is somewhat uncertain, because the current designation (which takes the tracks through a residential part of Onehunga) is seen as an unlikely route compared to taking the line along the motorway across Onehunga Bay. This would mean trenching/tunnelling under Hillsborough Road (because of the steep grades) potentially extending quite a way towards Dominion Road, which means a whole lot more money. So if we’re looking for “low hanging fruit” we probably don’t really want to go east of Dominion Road.

Which leaves us with a branch line off the existing Western Line, extending for about 3.5 kilometres – with two additional stations: that I have called “Owairaka” and “Mt Roskill”:First things first, it’s important to note that this branch line is not feasible until after the City Rail Link has been constructed. Until this project is complete, the Western Line has a capacity of 6 trains per hour (plus any that don’t go into the city), and it would be silly to split that capacity off when much of the Western Line’s patronage comes from west of Mt Albert Station.

However, post CRL the Western Line’s capacity becomes significantly increased and we could potentially run something like four trains per hour along this branch, six trains per hour along the Swanson-city centre section, overlaid to provide 10 tph between Mt Albert and town. I’m not quite sure how this would fit into previous service pattern diagrams that I’ve drawn up, but we could find a way of making it work.

I suppose the next obvious question to pose is whether services along this branch would be popular or not. Obviously compared to Sandringham Road and Dominion Road bus services, the rail line would be taking a fairly indirect route – swinging much more to the west before heading into the city. But of course at the same time it’s a rail line (and the new section could presumably be built to quite good alignment standards allowing for fairly high speeds) which means it can bypass congestion.

To get some idea about how timings might compare between catching a train or a bus from either the Owairaka or Mt Roskill stations, I first looked at the average speeds of trains along the Western Line that is expected after the City Rail Link has been completed (using this table from the CRL business case). A number of trips indicate an average speed of around 30 kph, which suggests that Owairaka to Aotea (9.83km) could be done in just under 20 minutes while Mt Roskill to Aotea (11.58km) would take just over 23 minutes. I think both timings are fairly conservative as the new section of track should allow for much higher speeds than is currently possible along the Western Line.

In comparison, most Sandringham Road buses that pass around where the Owairaka Station would be located seem to take 30-40 minutes during the morning peak to travel into the city. Even the 7.48am 243 express bus takes 42 minutes to make the trip. So catching the train would offer a significant time advantage – even taking into account a 7 minute wait at peak times (average wait if we offer 15 minute frequencies). Turning to Dominion Road, timetables indicate a trip length of around 30-35 minutes from Mt Roskill shops into town and about five minutes longer from May Road for services travelling from that direction. This once again indicates a time advantage for rail, although perhaps not to quite such a significant extent.

One thing to take into consideration in all this is how these two stations might be useful in helping to reduce the number of buses that will feed into downtown from the southern isthmus in future years. We know from looking at NZTA’s passenger transport study into the Waitemata Harbour Crossing project what the bus numbers along various key arterial routes will be in 2041 in both the “with CRL” and “without CRL” scenarios. I have bundled together the key data from those maps into the table below:The “Symonds Street (over CMJ)” numbers are of most interest to this particular rail line, because they include Sandringham Road and Dominion Road buses (along with New North and Mt Eden road services). We see from looking at the table above that while the CRL makes some difference (162 buses per hour rather than 244), even in the “with CRL” scenario we end up with almost a tripling of bus numbers: up from 56 at the moment to 162.

If we realise (as I outlined in this recent post) that there’s really no way the city centre can handle as many buses as is being proposed for it even in the “with CRL” scenario, then decreasing the number of bus services from places in the southern isthmus by shifting them onto rail starts to make a lot of sense. Perhaps most bus services south of our two new stations would be regular feeder services to those stations, with passengers given the choice of continuing along regular bus services to the city, or shifting onto the train.

All up, I think the rail spur proposed above would be a very useful addition to our network after the City Rail Link is constructed. Not only would it be fairly quick and easy to construct, it would also offer a speed advantage over catching the bus (and probably driving) for those currently living in the southern part of the Auckland isthmus and it would help ease pressure on the need for us to keep adding more and more bus services, by shifting those trips to rail. It would also be likely to significantly ease congestion along both Sandringham and Dominion Roads if the service was attractive enough. A pretty useful “low hanging fruit” I think.

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  1. A corollary to this, also post CRL and Airport Line, is the idea of extending the Mankau Line across SH1 and along the existing RTN designation to Botany Town Centre. This would go a long way to healing the severance caused by the motorway down south and at once help build Botany into a connected transit centre and hook the south east into the airport. Again providing useful cross city connection.

    1. The problem with extending Manukau is you would either need to tunnel under the motorway or bridge over it and take out a whole heap of homes, neither option will be cheap and there is probably no point in doing it unless you went the whole way to Botany. In the end it would cost hundreds of millions if not over $1b.

      1. Yes this is a much bigger job than the already largely formed and much shorter one above. I am certain though that once the CRL is operating the spreading benefits of the rail network will be clearer for many more to see, and therefore additional projects will, I’m confident, face much less resistance.

        It’s already gaining unstoppable momentum. October 1.2 million trips!; up 55% on the back of the RWC.

      2. The cheaper, easier option is to take advantage of the huge central medians along TI Drive to install some form of light rail that hubs into the Manukau station. Given that we’ve talked in here about putting in MRT on the AMETI corridor, having it coming in from the south as well would provide for a loop that terminates at each end at a rail station (Manukau to the south, Penrose to the north), can be constructed much more cheaply than “real” rail, can be constructed within existing road corridors (there are huge medians and verges along TI Drive, Harris Road, etc) for a lot of the length, and will cope with the grades to get across the motorway just fine.

      3. From what I’ve figured while looking at the route a short viaduct then bridge over the motorway followed by a tunnel is the easiest way to get across to the Te Irirangi corridor. Doubt you’d see much change out of a billion just for that though so it would have to be part of a much large line to be worthwhile.

        Light rail or light metro would be a lot cheaper due to less design constraints, but that doesn’t solve the issue of what to do at the other end of the line from Penrose or GI back towards the city.

        1. Transport exchange onto the Southern Line. By the time this happens, we’ll have proper integrated tickets and people will hopefully be used to the concept of switching modes in order to complete a journey. If we look at this problem from a perspective of “must be end-to-end” we trap ourselves into continuing the same historical mistakes that have so dogged our public transport to this point.

        2. I’m not sure how successful an orphaned line between interchanges with the eastern and southern corridors would be, at least one end should be anchored at a major destination (i.e. the CBD) if not pass through it.

        3. Nick, I’m premising on it being MRT rather than heavy rail. If a heavy rail line is built, which I think is economically unlikely, then it’s a no-brainer to join it at GI/Panmure. However, since MRT is more likely, an “orphaned line” is probably the only real option.
          That said, running MRT out along EPH, Campbell Rd, Mt Albert Rd, would link together the Eastern, Southern and Western lines, provide a very useful inter-suburban link in an area that is currently not well-served by buses, and give a sense of purpose to a south-eastern MRT.

        4. Yes I follow you, but it seems to be something of a tricky situation. Either a very expensive heavy rail line, a cheaper light rail/metro line that only serves to link two suburban lines (not much better than a decent busway if that is the extent), or a cheaper light rail/metro line with a very expensive extension and no obvious non-tunnelled corridor.

          A new metro line tunnelled (or perhaps elevated) across the inner south east would be fantastic, but that would eat up all the cost savings of using light metro in the outer east, and then some. The best I can come up with so far is to follow the existing eastern heavy line with a light line from a new CBD tunnel (shared with the northern line) to GI, then crossing the Tamaki to Te Irirangi from there. Cheapest and feasible, but it only duplicates an existing route on the inner half.

        5. yeah, clearly it’s either the real and fully connected thing or back to buses…. If you’re changing anyway i don’t see how you’d justify the cost of anything more than buslanes..

          Any I’m losing confidence in integrated ticketing… what are they doing? Looks to me like someone is losing their bottle. Yes there will probably be a drop in revenue for some whole journeys [isn’t that part of the point] but surely it will lead to the whole ‘pie’ growing? Ie it will make PT a viable and rational option for many more people which will bring more total revenue to the PT system. Are there squabbles among the players about how to divvy it up, perhaps? Ah, don’t you just love a ‘mixed ownership model’?

  2. Great concept. Given the earthworks are already in place this is something that could be built very cheaply, relative to just about any other possible transport link in the city. Tacking this on to the CRL project could be a very useful way of illustrating to the public and politicians one of the greatest benefits of the city tunnel (the fact it allows new suburban lines to be opened), plus factoring in the projected patronage could boost the CRL business case.

    One question though. My understanding was the formation was pretty much done to Hillsborough Rd (rather than Dominion Rd), and it was the section east of there that was difficult to construct (either via the old reservation or via the motorway corridor). So why not build this branch to a station at Hillsborough Rd and have three stations instead of two, each of which would connect with three sets of busy bus routes?

    The only problem I can see is with the residents around Alan Wood Reserve. After all the battled to get the SH20 motorway mostly underground through there so they might be a little upset about an above ground railway. Perhaps a station adjacent to New North Rd might sweeten the deal, even if it is quite close to Avondale and Owairaka anyway.

    1. The problem with going to Hillsborough (which Josh also points) out is that you are then stuck using the existing designation which winds slowly through the residential areas of Onehunga which is not going to be easy to do, Also Dominion Rd hasn’t had the rail corridor bridged over yet so that would add extra cost. The other option to follow the motorway also has issues due to the massive hill it would need to climb and to get from effectively sea level up to the flat area of land from Hillsborough onwards you would need a tunnel pretty much from east of Queenstown Rd all the way to Dominion Rd which is about 3km and that may be to steep to allow freight trains to use it which was the whole point of the designation in the first place.

      It should also be noted that the existing designation goes to the north of the town centre and doesn’t connect with the existing Onehunga line until between Alfred St and Church St

      1. Hang on, the existing rail designation and the motorway corridor only diverge east of Hillsborough Rd. So it’s not a case of getting stuck with one or the other for the rest of the route if you terminate at a station just west of Hillsborough Rd, either would still be an option (even if the subsequent tunnel option ended up rebuilding the station underground).

        I didn’t realise the Dominion Rd bridge hadn’t been built with the rail overpass like the others, so that would add quite some cost. But it appears that the rest of the corridor is clear and the Somerset Rd footbridge and Hayr Rd bridge look like they are designed to overpass the rail line.

        As for the travel times we’d be looking at around 25-26 minutes to Aotea. The timetable for the trip to central Auckland is 16 minutes via Mt Eden Rd (to Symonds St) and 22 to Britomart, but also 31 minutes to Newmarket via Gillies Ave. So it’s not quite competitive with buses on paper, but of course buses can be subject to lengthy delays in traffic while our EMUs should be generally delay-free.

        I still think it would be a good idea to maximise the number of stations on the branch if the extra cost of getting under Dominion Rd was reasonable.

        1. The problem though is that if you went with the tunnel option you would end up having to replace that track in the future which would be seen as a waste of money by many and not a good advertisement for rail. The Dom Rd interchange would also not just be building an underpass but it would probably require alterations to the ramps so not cheap.

        2. That would be the same deal with Onehunga station too though, but thats no reason to not have Onehunga in the mean time.
          If we get to the point of building the tunnel option then we’d already have the CRL, an airport line and who knows what else. At that stage rail would be pretty well supported and undergrounding one simple station probably isn’t going to be an issue.

          Looking at the aerials of the Dominion Rd interchange it looks like they’ve designed it as quite a tight diamond, so not sure if the ramps themselves would be affected. It would be very similar to what they did at Northcote Rd for the busway, if anyone can put a price on that.

        3. Just been thinking about the line to Onehunga along the motorway route.

          The rail corridor at Hillsborough Rd would be 60m above sea level (if it passed just below the road). The reclamation on the Onehunga foreshore is about 3m above sea level. So at a freight-comfortable 1 in 40 grade this drop requires an inclined section of track 2280m long. One can see why they though an enormous tunnel would be required, but I’m wondering if a viaduct might be a hell of a lot cheaper.

          By my quick calculations a route could start from a station just west of Hillsborough Rd, start to drop through an open cut about 700m long through the crown of the hill, then continue on a steadily sloped 1 in 40 viaduct approximately 1500m long reaching ground level alongside the Onehunga lagoon. This would mean a rail viaduct passing about 8m above Queenstown Rd, and quite a significant structure in the valley. However it would certainly be cheaper than 3km of tunnel.

    2. The other issue with going to Hillsborough Road is that your indirect route just gets more and more indirect for people travelling to the city centre or Newmarket. I think at this point the bus is probably faster.

  3. The idea of a spur to Dominion Rd is something I have been saying for a few years now as the rail right of way will have been mostly constructed as part of Waterview leaving only New North Rd as the main obstacle, I also believe that space for a station at Owairaka has even been left as part of Waterview. Grade separating New North Rd might be 10-20m but other than that the majority of the work would be simply building the formation and laying tracks so all up might end up only around 50m.

    As you point out the trip would be faster than peak bus trips so could be quite popular and would enable buses from south of the motorway to feed into the rail network which would have other benefits and critically it allows us to keep momentum up on improving the reach of the rail network without having to spend hundreds of millions of dollars at a time. It also creates a missing piece that needs to be fixed, just like the motorways always seem to have.

    As for the speed, I read in one part of the Waterview documentation that the designation had been designed for speeds of 90kph which is a little bit higher than the western line which has a max of 80kph. I also based on my own calculations I think that your speeds a are bit to slow and seeing times about 3 minutes faster might be possible.

  4. If you go here: http://www.nzta.govt.nz/projects/completing-wrr/docs/20100313-project-overview.pdf The second to last and third to last maps clearly show, in purple, the rail line. Have NZTA gone for consent for this along with the highway? Doubt it, well they’re drawn there all the same. Richardson Rd overbridge is an ideal place for a station; good interchange opportunity with bus and would help to revive an otherwise sad set of shops. The Dom rd location looks less ready, like no one was really planning for it… quite a narrow strip of land east of the off ramp, would involve a bit more work. Again good bus interchange possibility.

    1. The NZTA didn’t need to go for a designation for it because one was already there, they have actually used some of the rail designation for the motorway but as part of the process have had to take additional land so that the rail designation can be shifted and retained. That is one of the odd things in Auckland about the Southdown to Avondale route, it is a rail line that has not just been a nice to have line on a piece of paper but has actually been designated and has been so since about 1947.

    2. Careful with those plans – they are way out of date with the Board of Inquriy process having worked them all over heavily. However, the rail designation has been retained (in some cases shifted, as NZTA are indeed using land designated for rail) and the new civil works will either future-proof, or outright provide for the rail line. For once, a good example of integrated planning.

  5. Onehunga line is approximately 3.5km long, track cost $10M
    Dom Rd spur is about 4km long, assume the corridor is prepared to a similar state, so say $11.5M
    Onehunga line stations had an average cost of $1.2M.
    Electrification cost. Masts, portals and wires were $80M/80km. So that’s $3.5M for this spur. There are 3500 masts / 80km, so 175 foundations needed for this spur, estimate cost $5.7K each, total $1M.
    Total $18.4M so far.

    That leaves the partial rail trench, 4 lane New North Rd bridge and approaches, and the Hendon Ave intersection. I guess some land would have to be purchased in order to be able to divert the road and construct the bridge, as the road lanes and footpaths are reasonably narrow. Pak’nSave is in the process of extending it’s building towards the road, so this means probably buying some houses on the other side. The Hendon Ave intersection will need raising to match the bridge approaches making driveways for at least the corner houses quite difficult to construct. Guess trench $2M, property $2M, approaches $4M, bridge $4M, Hendon Ave & intersection $2M, so say another $14M. It may be cheaper/easier/safer to close Hendon Ave at this intersection and divert traffic via Ennismore Rd.

    So that’s about $32M.

    1. I was thinking that it would fall within a $50m funding envelope so probably not that far off considering this is double-track and the Onehunga Line was only single track.

  6. Wouldn’t it be done as part of the wider project though?

    So electrification, trackwork etc… and labour economies of scale?

    I think it’s a great idea. Onehunga has been a success and this would provide great resilience if the Western line west of there went tits up.

    It’s also efficient in terms of units (stock hasn’t been mentioned) having close turnbacks – especially for peak services to return to ‘suburbia’ and come back to the city still within the peak period.

    Would also boost frequency for Kingsland which is set to miss out under some plans – if it went via Newmarket first.

  7. None of the SAL rail formation has been constructed. It’s just a reserved strip of undeveloped land, so full formation construction costs will need to be factored in.

    Look to Manukau for a cost estimate, where they also had to build new formation on empty land – would be in excess of $100m for a Mt Roskill spur. Knowing NZ’s costings, probably $200m+.

  8. Considering the CRL project includes the grade separation of the western line plus the double tracking of the Onehunga branch a lot of the work would already be done for these sorts of extensions. I wonder if this branch and an extension of the OBL to Mangere town centre could be added to the CRL project? That would increase the cost by a few hundred million but would add five or six stations but presumably increase the projected benefits substantially. The name would have to be changed to something like ‘city and regional rapid transit’ or something, but that would only serve to illustrate the systemic benefits of the CRL.

    1. The original report just states that grade separation of a couple of key roads, duplication of Onehunga and additional trains (above the 57 on order) would be needed and gives an estimated cost to do this but isn’t actually included in the cost of the CRL itself.

      1. Yes I see references to $100-$120 million, I thought it was included in the total cost though… but that is kinda my point, why not add these costs plus our Mt Roskill branch plus an extension to Mangere town centre onto the project. Sure that turns a $2.0-$2.4 billion project into a $2.5-$2.9 billion one, but it also greatly expands the scope of the benefits in a way the public can grasp.
        Just the other day I read another letter in the Herald talking about how no one would ever use “Len’s stupid loop going round and round downtown”, people still think the point of this project is just a couple of stations in the city and can follow the fact it unleashes the whole system. So let’s include a bit of that unleashing in with it from day one, then the debate can talk about three new city stations, vastly improved suburban frequencies, a new branch line and stations in Mt Roskill and an extension of the line most of the way to the airport. That will get the public’s attention in the right way.

        1. I may help the BCR and the practical benefits, but it also makes the rail tunnel an ever easier target for it’s opponents.

        2. Because of the “ever-increasing price tag”, I mean. Sure, the experts and nerds like us will get it, but don’t underestimate the potential damage such cost “escalation” things can do among the general public.

        3. Yes I agree with Max here, anyway I think the the best way forward for everything except the CRL is to get funding for as much as is politically achievable and build it. Then on the back of its success, build the case for the next bit, especially by appealing to the logic of ‘complete-ism’. This has worked so well for the motorway lobby, so much so that they now face the problem of needing a new story, as the network is nearing functional completion.. Clearly everything recently built has exceeded expectations [Onehunga, double tracking, station upgrades, etc] and if we are smart from here, especially with integrated ticketing, there is no reason not to expect continued and compounding success, as the general social and economic climate is also with expanded rail use.

          Having said all that, it is essentially a political plan, not a logical transport plan. There I agree with Nick, and the Airport Line should be built to come on at the same time as the CRL. But we do have to work with what is possible and that depends on what happens on Saturday.

  9. Rather than terminating at Newmarket, you could send this down to Onehunga (if it was doubled at the same time)- would almost be a circle line!

    Or Otahuhu/Manukau if not.

  10. “Part of the site was sold to Transit for the development of a train station at the rear of the property. This provides an opportunity for IIP to redevelop their site for alternatives like a neighbouring shopping hub with a range of users. Strategically located at the intersection of key arterial routes and the new motorway, and serviced by excellent public transport connection, the site is set for redevelopment to capitalise on these areas of significant growth,” Infratil said before selling to Ansley.


  11. Why not build the line now, have the Onehunga trains loop around to Roskill not via britomart (meaning they don’t decrease the capacity of the other lines), and try to time a western or southern train at newmarket just after the onehunga-roskill line train arrives for passengers to get to britomart. This would hopefully increase total rail trips and get us to the CRL target earlier.

  12. “So at a freight-comfortable 1 in 40 grade”
    1 in 40 is not freight comfortable; it is severe. It really would not be wise to make this the ruling gradient for freight trains heading north.

  13. Apparently the CBT have made this one of their campaigns, although I only found out today after seeing who was behind the petition to have it built. I think CBT forgot to actually announce this campaign? Never seen a press release, and there’s zero mention of it on the CBT forum. Might pay to actually launch the campaign at some point?

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