A couple of days ago I lent an ear to a conversation between fellow bloggers Patrick Reynolds and Matt L over the fate of train service patterns around Newmarket station. They were particularly concerned with the best way to run a service so that people can travel easily between the west, the city and the south… in any direction.

On one hand Patrick was suggesting it was time to embrace the transfer model and create a real ‘network’ out of our rail lines, a network that services travel across the whole region all day rather than just shuttling office workers to downtown at peak hour. This is something I totally agree with. However he also suggested that running all trains from the west to south would be a good idea to facilitate this sort of cross town travel, and that Britomart bound passengers could simply transfer at Newmarket for the rest of the trip. This set of little alarm bells inside my head. While we do need a cohesive integrated network – and transfers are the cornerstone of such a network – we do need to recognise that transfers are usually an inconvenience and it pays to not break the main flow of travel unnecessarily. Going west to south with all the trains seems to be mostly about fitting the services in around the infrastructure constraints, not designing the network to suit the travel needs of our citizens.

On the other hand it seems Matt L agreed with my thoughts. He thought that the core flow was going toward downtown, and changing that would upset a whole lot of people’s trips for a lesser gain elsewhere. But he did recognise the value of linking the south and west lines together. Matt’s suggestion was to do both, send four trains an hour direct to Britomart, and two trains an hour from west to south via Newmarket. This also set off alarm bells. Do we really want to have two service patterns on each line, where 2/3 of trains go one way, but every third train goes somewhere else? That means a funny timetable with funny frequencies, which makes just turning up at the station and heading off on the next train an issue. It’s kinda funny that proposals like this that intend to open up new origin and destination pairs often have the opposite effect: they make catching the right train infrequent and irregular. This kills of the “just turn up and grab the next train” sort of plans you can make with a frequent and regular service.

So I found myself in the conundrum of both totally agreeing and totally disagreeing with both of them. It really is quite a pickle: effectively we want trains that have a single regular service pattern, yet somehow magically take us directly across each line on the network too. We need services the support the main travel demands headed to the CBD, yet also seamlessly support the various travel patterns across the network. And we need to do this all with limited resources and an understanding that there are only so many trains we can fit through our junctions and stations.

Is this asking the impossible? Perhaps not.

Last week I was lucky to attend a transit network design workshop run by the inspiring transport guru Jarrett Walker (of Human Transit blog and book fame). The workshop was based around a series of fun network planning games where teams were given a large map of a fictional city complete with topography, land use and density data and a fixed budget of transit service and other operational constraints. Our task was to design a network within these bounds to meet various planning goals and evaluation criteria. Through much drawing of lines on maps and fiddling with spreadsheets, we all came to grips with the fundamental tradeoffs and hidden efficiencies that lurk in the geometry of transit networks. At the end of the day my team did quite well. We developed a strategy of planning out a gridded network of high frequency routes and focussed on running them at 100% operational efficiency to extend the network as far as possible. This strategy paid off in most regards: we ended up with a nice logical network that our fictional citizens could easily transfer around to get almost anywhere. In terms of efficiency, coverage and legibility we excelled. However there was one criterion in which we were consistently beaten: travel time. No matter how great our efficiency, we just didn’t have the resources to get enough high frequency service to enough areas to make our transfers invisibly quick. In many cases we had connections taking fifteen or even thirty minutes, and that eats into travel time.

The faster groups took a different approach. They had a strategy of providing a lesser level of frequency overall but coordinating transfers between routes around timed connections at key locations. This is called pulse timtabling, and it allows us to do amazing things. The key to it is that two or more routes are timetabled to arrive at the same stop at the same time, this means that anyone can transfer from one line to another at the pulse point without any time delay, simply by walking across the bus stop or train platform. Transferring takes only as long as a regular mid-route stop, and because each of the routes would stop at the pulse point anyway, there is no delay to passengers who are staying aboard and not making the connection.

It’s quite common in smaller European and American towns as a strategy to provide a good interconnected network with minimal transfer delays, in places where the town cannot afford to provide the high level of frequency needed to make transfers simple. In places like this you have a central hub (usually the main street or an intercity railway station) where every bus line terminates or passes through. Most of the time there are no buses around, but every thirty minutes every bus in the town arrives at the same time. Some people get off, some hop on, and some step out of one bus and straight onto another. The buses all then depart for their routes, and return a thirty minutes later to repeat the process, over and over all day. The critical thing is that it provides a tiny time delay when transferring that is independent of the frequency the lines are run at.

There are some tradeoffs with pulse timetabling. For one you actually have to plan and coordinate a timetable across the services you want to pulse. In Auckland that should be feasible with the rail network and perhaps the ferries (the Waiheke buses are actually pulsed to the ferry already), but perhaps not on the rest of the buses (not until we have the new PTOM system in place anyway) which are timetabled and run by various independent operators as independent routes.

How a timed connection at Newmarket could work. The trains already use these routes, it's just a matter of timetabling them to arrive at the station at the same time.

Secondly you need to run a consistent clockface timetable. If one of your pulse routes runs every fifteen minutes, all the connecting routes need to run every fifteen minutes too. If you want to drop the service to hourly on one line to safe money, they all have to drop to hourly or you lose the timed connection. This also has implications for efficiency, you have to plan at a network level which in some cases means an individual line might be quite inefficient. Imagine you need a bus route to turn around every hour to meet the pulse connection, but the route itself take an hour and ten minutes to cover. In that case you’d either have think about cutting the route short to make up the time (losing coverage and paying passengers), or you need to pay to put on extra buses to cover the whole route (which also means they’ll spend most of their time sitting around empty waiting for the timetable).

The third major constraint is you need a fare system that allows for transfers. We’re not quite there yet in Auckland, but we should be soon. On the rail system it could be quite straightforward to extend the existing paper ticket stage system across all the lines. For example if a trip from Kingsland to Britomart is one stage, and Britomart to Greenlane is two stages, they could simply say that Kingsland to Greenlane is two stages also. All that would require is a little transfer ticket to show the clippie you had already paid on the first train.

While there are some constraints here, the benefits are huge and with a little effort we could see timetabled connections in Auckland. Going back to our Newmarket conundrum, a pulsed connection could be the answer we need to meet our impossible goals. So how could this work?

Well to start with we’d need to assume the western and southern line ran to the same frequencies at the same times of day, which sound quite reasonable. Then it would simply be a case of shuffling one timetable back or forward until they meet at Newmarket at the same time. So every fifteen minutes during the peak a citybound western line train heading to Britomart arrives at Newmarket platform 3, and at the same time a southbound southern line train arrives from Britomart arrives on platform 4. Both trains open their doors and people can transfer from the western line to the southern line by simply walking across the platform to the waiting train. A few minutes later the opposite happens: a westbound train arrives from Britomart on platform 1 at the same time a train from the southern line arrives on platform 2. The doors open as usual and people can hop on or off either train, or connect between them. Again because both lines stop at Newmarket anyway there is no delay to passengers on the regular service, and your overall time from west to south or south to west is exactly the same as if the train actually ran through that way. And at the end of the day making a transfer from one train to another across the same platform is about as hard as shifting from the couch to the lazyboy on the other side of the lounge, so it’s hardly even counts as losing a one-seat-ride.

So is this our solution? Well it could be. A pulse timed cross-platform connection at Newmarket probably represents the best option for excellent west to south rail connectivity while still keeping a frequent and reliable ‘turn up and go’ service pattern along the main route to the CBD. The only issue I can see is at the Britomart end. With only twenty train slots an hour across the network and very busy trains, we don’t really have any spare slots to hold trains around to fit the pulsed timetable. I guess it would come down to whether the transit times happen to work out in favour and an efficient timetable could be put together. At the end of the day, if we can wriggle the timetable to give a timed connection at Newmarket then we should do it. It would cost nothing but a little planning yet gain an almost seamless link between all the stations on the western and southern lines. That’s a huge benefit for almost no cost.

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  1. It seems like pulse timetabling becomes increasingly necessary where you have lower frequencies. If everything is coming and going every 10 minutes then a pulse timetable seems unnecessary. At lower frequencies it becomes essential.

  2. Great post Nick. Peter I actually think that on a rail network pulse timetabling should be the default setting: Even at 10 minute frequencies an average 5 min wait (assuming uniform, i.e. random, arrivals) is quite significant. After all, if you can do it – why not?

  3. A few questions.
    1. How do you handle delays in this system? Do you you hold up one line if the other is only a few minutes late or let it go?
    2. Could you combine pulse timing with a western/southern pattern? Ie have trains go from Henderson to Manukau via Newmarket pulsed with Southern line trains at Newmarket. This could free up capacity at Newmarket and allow frequencies of higher than 10 minutes across the major lines.

    1. James that was my original thought; do the transfer the other way and cut the inelegant reversal of western line trains. Matt and Nick probably have a strong argument about not breaking the primary destination (to Britomart)) so it would be good to see the numbers that do get out at Newmarket. The other problem as Matt pointed out to me was that what if, and with current service levels this is common at peak, the southern line trains are too full for people to transfer onto them at Newmarket? Stranding city bound workers at Newmarket not a good look.

      I have a hunch that west south, especially when MIT opens above the Man City station could be very popular, but only if it is easy and efficient and we design a service pattern that supports it. Certainly better frequency at MC and efficient transfers, especially at Newmarket. A real network in other words, even post CRL.

      So good solution Nick; are the operators up to it?

      1. James: Delays in the system will be inevitable, but I think that isn’t a reason to not do pulsing. For a start we are actually quite lucky with the dog leg turnaround at Newmarket and the fact it takes about 3 minutes (well in this regard at least). That gives us three minutes leeway to make the connection, after all it doesn’t matter if the second train arrives in the first 15 seconds or in the last three minutes, people will still be able to make that connection. That’s much easier than something like the Hong Kong Metro, where they pulse to 20 second windows.

        There is some potential to work a little extra fat into the timetable to give a few more minutes grace, but at the end of the day if things go wrong then people just miss the connection sometimes. Missing the pulse then leaves people no worse off than if they did the old ad-hoc transfer anyway. Here the base case is what we do currently, and any timed transfer simply improves things over the status quo.

        Patrick: Yes I think, all things being equal, one should keep the larger travel flow intact and require transfers on the less patronised route. I figure the Britomart connection is going to be the greater demand for a long time yet.

        The good thing about doing the transfer the way I proposed is that you are pulsing an inbound to an outbound, so you’re utilising the space left vacant by people getting off at Newmarket. This is rather than trying to transfer an inbound load of passengers onto another full inbound train while new passengers are also trying to board from Newmarket (or vice versa in the afternoon).

        There should be no real issues about pulsing at Newmarket and again at Puhinui for Manukau. You’d basically set the southern line timetable then adjust the Western and Eastern lines to suit. Again the only roadblock would be the scheduling in and out of Britomart.

  4. I agree that if we can do it, why not, but at ten minute headways the optimization of access to Britomart would probably be the more pressing issue. But if we happen to get lucky and can do them both then why not indeed, it’s zero extra resource for a huge gain.

    The real value of this would come in the off peak when frequencies could be around the half hour mark, or worse. At that point the transfer could take longer than the rest of your journey put together.

  5. A tough one when especially when Newmarket can be a source of delays in itself and the station is built just plain wrong for starters.

    Best bet and sadly the most costly and disruptive but offers the highest return to all is demolish Newmarket (I hear it is due 2015 any how) and rebuild the station with a Western Line Track connecting to Platform Four (was in the original plans). That way you can go Grafton, Newmarket via Platform 4, then south with that same train through to either Sylvia Park (if they rebuild the Diamond) or through to Manukau. After that the train goes in full reverse back the way it came.

    Just on casual observations with Newmarket, I have seen a few passengers go West to Ellersile or Onehunga and vice versa with the odd lot pushing further south to Middlemore – so the demand is there.

    Just a bugger Newmarket was built wrong to start with

    1. I don’t think we would have to go as far as demolishing and rebuilding Newmarket station at enormous expense, and wonder whether that would even be possible.
      I agree though with the sentiment that the current Newmarket arrangement is more of a hassle than a boon and will be a bottleneck in the future.

      Instead, just rebuild the Newmarket West station to a permanent standard, and build the planned northern concourse for the main Newmarket station. There could then be a clearly marked 300m pedestrian route between Newmarket West and Newmarket South, which most people should find acceptable (and if they can’t then they can transfer at Britomart).

      This would make peak hour Western, Southern and Onehunga Line services more reliable, and Western Line services in general faster.

      The redundant third track at Newmarket South could then be used for the Overlander and future regional trains. At 180 meters (IIRC) long it could fit a consist of any likely length without shunting or decoupling.
      Newmarket has better transport links and services, and would leave a better impression on tourists, than eastern Quay Street. The Newmarket station building is also already a high point of Auckland’s rail system and arguably world class.

  6. can anybody explain simply how the CRL intends to work in terms of routes? I’m confused. if travelling from the west will you have to go through Britomart to get to Newmarket? will there be a train running between Aotea and Newmarket (apart from via Britomart)? I can’t get my head around it!

    1. No, no one can because they are still working out the routing. Admin and I have a favourite arrangement that we think would be ideal, but there are many possible combinations that might be implemented.

      In our scheme you have one line running from the west through the tunnel to Britomart then back south via Newmarket. The other line comes in from the east to Britomart, through the tunnel, over to Newmarket via Grafton then on south to Onehunga (and the airport eventually).

      That means from the west you can either go via Britomart for a longer one seat ride to Newmarket, or you can transfer at Newton for a shorter two seat ride. No reason that connection couldn’t be pulsed either. Aotea would have a direct link to Newmarket in both directions, via Britomart on one line and via Newton and Grafton on the other.

      It sounds like a winner to me.

      1. that sounds the best…but that relies on them building a connection between Newton and Newmarket. will they build that?

        1. Well that’s the question. Going back to the 2004 URS report there has always been the suggestion that the cheapest option would be to only connect the western line to the tunnel at Mt Eden, so there is the chance they’ll try and pinch pennies by not building the tracks between Newton and Newmarket.

          That would be a serious balls up in my opinion, it would majorly limit the ability to run an efficient and effective regional network if you have only the western line on one end of the tunnel, but the Southern and Eastern lines plus the Onehunga and Manukau branches on the other. If you think about that you’re two billion dollar tunnel is effectively limited to what you can run on the Western line. Anthing else through the tunnel is kinda wasted running.

          1. Hope they prove us wrong but it seems the powers to be would do such a thing to the CRL.

            The Manukau’s lack of a “southern” link does not inspire confidence right now

      2. The problem with that is that you have conflicting moves at Newmarket and Penrose. That might not restrict capacity but it does impact on reliability. The ideal would be extra trackage between those stations. An alternative is terminating at platform 4 at Newmarket. Still has the conflicting move at Penrose but removes the merge on the outbound, which will no doubt cause headaches.

        1. Can you elaborate on that Simon, I can’t quite follow you regarding Newmarket. I do have one concept for a pair of flyovers (one between Remuera and Newmarket, the other between Newmarket and the Parnell tunnel) that allow Britomart bound southern line services to utilise platform 4 northbound, which effectively grade separates every movement that would occur through Newmarket.

          Penrose could be doubled, and if that wasn’t enough then a flyover/under would be fairly straightforward to build in that unconstrained area.

          1. Hmm, if there are flyovers in both places then that means that there aren’t conflicting moves. The problems of a diverge and merge remain. That means timetabling has to deal with having trains coming from different places with different section times more than once on their trip. You won’t see Paris’s RER doing that!

            Regarding Newmarket, if trains via Grafton from the CRL terminate at the Western Platform leaving two Eastern Platforms dedicated to the South and Onehunga lines, there is no interaction between the lines. That is the sort of thing Cityrail’s clearways project is trying to reduce.

            Is that any clearer?

          2. Ok I follow you now. One strategy would be to build in the tunnel grade separated junctions as part of construction, but leave improvements at Quay Park, Newmarket and Penrose until we get up to the twenty trains an hour per direction limit of a flat junction.

            One benefit of our proposed routing is that it removes the double back at Newmarket, leaves it as a normal junction.

            As for the RER, correct me if I’m wrong but my understanding is that they do have a whole lot of diverge and merge. There are relatively few tracks through their city tunnels, and at the periphery they branch out into various suburban lines. Quite similar to what we could have here actually.

      3. “In our scheme you have one line running from the west through the tunnel to Britomart then back south via Newmarket. The other line comes in from the east to Britomart, through the tunnel, over to Newmarket via Grafton then on south to Onehunga (and the airport eventually).”

        Although that looks good on a map I think routing west to east and Onehunga to south (bi-directionally around the cbd – where the southern line trains go to newton, and then continue via britomart, parnell etc to onehunga) is a better option.

        That way say west to east (say henderson to silva park) is a one seat ride, and west to south (say new lynn to remuera) is a single transfer at newton.

        Under Nick’s way the west to east travelers would have to transfer once. I want west to south travelers to transfer to 1. save them the time of going around the CBD as they would have under nicks plan (assuming they didn’t want to double transfer), and 2. to reduce passenger volumes in the CBD tunnel (I would pick the tunnel to be the busiest part of the line (passenger volumes), hence setting the system bottleneck.

        1. One thing to think about when putting together future operating patterns is where patronage is most likely to increase post CRL construction. Let’s say we go with Nick’s preferred west-south and east-Onehunga/Airport routing pattern (which has fantastic simplicity), if we run those at 6 tph the only place we’re adding trains to compared to the current situation is between Penrose & Newmarket on the Southern Line. I’m not sure that’s where our most pressing need to add capacity will be.

          I don’t know for sure, but my feeling is that extra capacity is most likely to be needed on the inner part of the Western and Eastern lines first – perhaps particularly the Western, as the CRL will bring the greatest time savings there.

          However, while matching up the East & West lines is fairly easy, matching up the Southern & Onehunga lines gets pretty messy. Trains between Penrose & Onehunga alternate between going around the link clockwise and anti-clockwise, not really offering any through-routing value.

          Food for thought though.

        2. One of the main motivations form my preferred scheme was to get the best trade off between access to central city stations and providing effective through routing.

          If you link the western and eastern lines then both these totally miss Newmarket, Grafton and Parnell. Meanwhile you are left with linking the southern and onehunga lines together which creates a route that not only loops back upon itself (a waste of resources as no one wants to travel in a full circle), but also has zero opportunity for direct cross town travel (as each train would just cover the same tracks outbound as it did inbound).

          Linking the western and southern covers all but one of the central city stations (Grafton) without creating a useless full loop, and provides a very functional through route from west to south. Likewise linking the eastern and onehunga lines means the cover all but one city station (Parnell), doesn’t create a wastefull return loop, and provides a useful crosstown connection.

          One further advantage is it pairs the lines that have the most similar length and patronage demands, i.e. the long and highly patronised western line is linked to the long and highly patronised southern, while the shorter and less busy eastern and onehunga lines are linked. This is good from an operational perspective, while you might have the eastern-onehunga only run a six trains a hour, you could bump the western-southern up to twelve an hour to meet demand. If you linked west and east, you’d probably end up with too little capacity on the western segment and too much on the eastern.

          1. I see your point Nick. I suppose I’m thinking of the potential for unbalanced flows between the west being really high demand and the south needing so many services (to balance with the west) on the parts where it shares track with the east/airport line to keep up with the west that you end up with problems.

            Under your scenario above you have 18 tph in each direction between Newmarket & Penrose and between Westfield & Manukau.

          2. Yes, there is the issue of the overlap on those four and three stations respectively which ends up giving them a whole lot more service than they could justify on their own… but that’s just an unavoidable artifact of a network that pinches together in those two places. I don’t see how you can avoid that overlap between the southern and eastern for example, unless you terminate the eastern at Otahuhu or something, and run Manukau as a diverging branch off the southern. Sounds messy to me.

            One intermediate outcome is to terminate half those eastern-onehunga services short at Newmarket (platform 1), so that the eastern line runs right through the tunnel to Newmarket but the onehunga branch only operates at half the frequency until such time as it is upgraded or extended.

            In my opinion it’s better to have a few stations with excessive frequency than to chop back frequencies in other places, or have routing patterns that aren’t particularly useful.

          3. Oh and a further solution to inner west capacity demands would be to run a ithsmus line or loop, using some or all of the inner west, inner east and/or the avondale-southdown route. That would allow further flexibility to add in capacity from Mt Albert inwards, and over on the east if need be.

  7. Pulsing works well in Palmerston North where the urban services and the direct Massey services are all the same length and meet at the central terminus at the same time enabling full connection between them. It’s interesting because we have a local councillor who is very keen to try the network approach, but in my opinion the well co-ordinated connection at a useful O&D point will prove hard to beat given the frequencies practical.

  8. RER has a whole lot of diverge on outbound and merge on inbound but if they have the reverse then that is news to me.

    1. So what is the problem with diverging inbound and merging outbound. How is that any more complex that the opposite? I do know that Melbourne does it plenty around its city loop – flinders direct business, and while that’s not exactly the paragon of efficient services it isn’t a major roadblock.

      The network I’ve suggested is a lot like the RER, but instead of the lines just sharing tracks in the central tunnel the also share them again between Newmarket and Penrose, and between Southdown and Puhinui.

      1. I guess if there is enough slack then I guess there isn’t a big problem. The thing is that the different travel times rarely fall directly into neat 3 minute multiples, and one train has to be slowed to fit in in many cases. I guess Auckland has a bit of growth to do in a post CRL world before it is worrying too much about that.

        1. Yes it would be a bit of a case of fitting the timetable to the infrastructure demands, rather than building the ultimate infrastructure to suit the perfect timetable.

          I think it would be quite managable to begin with, then over time things like grade separating Quay Park, Penrose and Southdown junctions could be phased in as they are needed. Probably the biggest hurdle would be making sure the new Mt Eden junction was grade sepp’d to begin with, as I understand it will be underground and probably very difficult to modify after the fact.

  9. Thinking about this in relation to the CRL tunnel seems really important. Kind of related, but I really love this infographic showing the evolution of the Lisbon metro over time. It started out on a non-transfer basis, but now extensively features a single transfer to get between any point. The metro also links in with the suburban train networks. FYI: most lines run at 5-7 min headways at peak times.

  10. Stu D (and Peter) are correct – pulse timetabling becomes more important as the frequency decreases, but pulsing should be the default no matter what frequency you run, so you are set up correctly for the inevitable drop in frequency for off-peak services.

    @ James B – every service should have a buffer time built into it – the time they have free to catch up to schedule. Pulsing doesn’t affect that. What is important is getting the vehicle order correct in the pulse. In the Newmarket example above, Nick R has correctly sequenced the trains so no-one misses their connection (unless a train is radically delayed).

    Looking at the West to South, the inbound West (green) train must arrive first. Why? Because if green arrives after outbound South (red) train, green passengers cannot connect onto red train. But the converse does not hold – red passengers do not need to get onto the green train, as the green train goes to Britomart after Newmarket, which is where the red train just came from. Hence, green train must get to Newmarket first.

    AT & Veolia have a long inglorious history of scheduling inbound West trains to wait at signals just outside Newmarket while they let an outbound South train through, ensuring no connection was possible. For no other reason than they couldn’t understand pulsing (I know this, because I asked at the time – their baffled explanations should have been funny, but…).

    The same need applies to match inbound South and outbound West – there red train must go first.

    All the other folks debating CRL network patterns – don’t forget there is more than one junction. Westfield is kinda important too, and Penrose to a lesser extent (and now Puhinui with Man City line). That’s when the timetable planners give up – when they try to pulse all the junctions simultaneously 😉 Can be done though.

    @ Nick R – your CRL network idea seems to have 1 track of the CRL for each service (West-South and East-Onehunga). So, do you want bidirectional running on each track, or alternating W-S and E-O services running in the same direction on each track?

    That is, bidirectional would be West to South and South to West running on the one track, and Onehunga to East and East to Onehunga running on the other track. That keeps the two services on separate tracks, but limits your frequency because it effectively makes the entire CRL a single section (ie an East-Onehunga train must wait for the Onehunga-East train to get out of CRL before it can enter; ditto for W-S).

    Unidirectional would be Onehunga-East and West-South both run on the left track, while East-Onehunga and South-West run on the right track of the CRL. That allows normal frequencies, but means you have points delays at either end of CRL (unless you grade separate the CRL entry junctions).

    Whew! Sorry for the convoluted explanations 🙂

    1. Hi bob. I’m not suggesting bidi running on a single track each, that would severely limit the possible headway and make things very confusing for passengers (trains departing either platform in either direction!).

      So it would be a case of alternating services, with all the Quay Park bound trains on one track and all the Mt Eden bound trains on the other. Indeed I have assumed points at either end, this is always going to be the case anyway because you have the eastern and southern line diverging from the Britomart end, and the western line and (hopefully) the line back to grafton and Newmarket on the other. There is no way we can operate services without at least one set of points in any case.

      As I noted above, what I would like to see is the CRL build with a grade separated junction at the Mt Eden portal. Then as patronage demand increases Quay Park can be grade separated at the other portal (this is pretty simple, only needs one track to fly over or under, probably an flyunder of the down out of Britomart heading to Orakei would be easiest). Following that there would need to be a single track flyover at Southdown to grade separate that junction.

      Up until this point I’ve assumed that Onehunga was still single track and probably half of the Eastern-Onehunga trains would terminate at Newmarket platform 1 during the peak. This delays the issues with Newmarket and Penrose for as long as we dont need ten minute or better services to Onehunga. If that gets doubled, and especially if it gets extended to the airport, then a flyover would be needed at Penrose. Newmarket is the only place where grade separation would be particularly difficult, but see here for my work around that achieves the same thing: http://greaterakl.wpengine.com/wp-content/uploads/2010/11/Newmarket-grade-separation.jpg This uses a flyover between Remuera and Newmarket to take southern line Britomart bound trains over to platfom 4, then a second one between Newmarket and the Parnell tunnel to get them back to the up main again.

      The beauty of this approach is we can start off the bat with a function CRL running six or eight services an hour each way on each line. Then we can phase in upgrades to junctions as and when they are needed (which spreads out the cost too) and get that up to perhaps twelve services an hour each way per line. At the end, when all junctions are separated it should be possible to run the network to the theoretical capacity of the CRL of 30 trains per hour per direction (i.e. four minute headway on each of the four lines, or a wider headway on a greater number of lines).

  11. Arguably, the time to try a West – South service is now, before any CRL is built. For as long at Britomart is a dead-end station and all services go to Britomart, the capacity there will constrain the number of trains running. There is in all probability capacity now to operate a (say) Henderson – Manukau service overlaid on the existing.
    This service would not just give direct links between the southern and western lines, but would also give a far better connection between Manukau and Newmarket than exists in the initial Manukau service. It would incidentally give a better connection from Manukau to the rest of the network if they were going south or indeed to Britomart.
    Designed right with connections at Newmarket it could increase the apparent frequency to Britomart for those willing to change without impacting on the direct services for those not willing to do so.

    1. That should also mean that you don’t need to reverse the western line trains at Newmarket which has to restrict capacity.

      Not a bad option, if rolling stock is available.

    2. Working on it

      Also pestering AT and a few Councillors too under the guise of “Rail Efficiency (Pre CRL) Program.” Will give it a shot at the RLTP hearing in two weeks if I can for you 😀

  12. Aaargh! Please don’t Ben! A direct South-West service is the worst of all worlds. Of course we want to minimise transfers, because they are inconvenient and add to travel time.

    BUT (and yes, I do want to shout this), overlaying another direct South-West service onto the network means:
    – alternating services on the West and South lines (and possibly Man City line, if it goes there), which causes passenger confusion.
    – worse frequencies, as existing services have to be canned to free up timetable slots for this extra South-West service, or because we don’t have enough rolling stock for the extra service.
    – extra cost for the extra service (if it is additional, rather than replacing existing services)

    And all those negatives, to save a few people transferring at [email protected]#$! Folks, let’s remember the whole idea of pulse timetabling is to make efficient use of existing services. It allows us to get South-West service by rapid transfers between existing West and South trains (while getting those trains to as high a frequency as possible).

    Remember – anything that involves an alternating service is an example of a badly designed compromise. 🙁

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