Transport expert Chris Harris is back with another Guest Post:
Has anyone suggested running North Shore trains through a widened eastern clip on?
Everyone says that the existing bridge is too steep to run trains over and that’s usually the end of the argument. Well, lets look at this more critically.
First, the clip ons are about ten metres deep. If we ran trains through a widened clip on, the trains would normally run inside and on the bottom, not on the top. That would lower the expected climb height of the train tracks by ten metres immediately, from about 55 metres down to about 45 metres.
We can also assume that the tracks would enter on a C shaped alignment which is not the same as the actual motorway lanes, allowing further easing of the grade between Britomart and Akoranga.
The clip-ons are each about six and a half metres wide. To accommodate two train tracks the eastern clip on would have to be widened by a few more metres. This would allow it to be strengthened further, thus eliminating life problems, and it would also create the space on top necessary for a proper walkway / cycleway.
The current strengthening work probably already goes some way toward what is required. We would just have to do even more strengthening work, buiilding on what has been done already.
The supports for the eastern clip on would need beefing up as well. However, again, I don’t see that as a show stopper.
Once this was done we could forget about additional harbour crossings for a considerable time to come, given the capacity of a decent electrified railway. So it saves nearly all the $4 billion or so that NZTA has budgeted for a new harbour crossing.
(Perth’s new Mandurah line in Western Australia carries 40,000 passengers a day. That works out to roughly 30,000 one-way car trips that don’t have to be provided for each day, based on average car occupancy figures.)
If we are very clever, we might be able to do all this while keeping the eastern clip-on open for business on top, as NZTA have mostly been able to do in their current round of strengthening works.
Lastly, having trains on the eastern clip-on doesn’t preclude them coming from the west, if trains were ever to go through tunnels in Herne Bay, as was proposed in the old Halcrow-Thomas scheme of 1950 (wouldn’t that have been great?).
The deck truss at the south end of the original 1959 bridge — i.e. the mesh of girders below the roadway — is so open that it might well be possible to thread train tracks through it without requiring any modification at all. If modification were needed, it would be minor.
At the southern end of the bridge, it should also be possible to go through the western clip on without causing an unfixable structural problem, bearing in mind that the loads are greatest near the middle, see here .
Rutherford once said, “We have no money, therefore we must think.” The government right now is making similar noises, though somewhat selectively in its choice of targets for cuts so far. Well anyway, I’ve sharpened my pencil in that spirit and come up with this scheme.
It is, admittedly, a very modest proposal, not nearly as “sexy” as a brace of new tunnels, nor an entirely new Anzac Bridge designed by a world-famous architect. Could that be why it hasn’t been proposed so far?
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I’ve been running a series on Perth. I think the figures for patronage on the Mandurah line have now grown to 50 000 or 60 000/day now.
They strengthened two bridges (Mt Henry and Narrows) to do this and also used the space between the existing bridges to add a section to carry trains.
Now I am not sure if $40 million is the total cost of getting the bridge expanded, but it does seem like something to look at.
The main thing would to be to get an assessment by engineers of the feasibility of widening or strengthening?
http://wyche.com.au/wp-content/uploads/2009/07/mackinlay_cvjul09.pdf
@Brisurbane – I agree, I was about to correct my underselling of the Mandurah line myself! I was using old data from memory, but the patronage keeps growing in a most encouraging way. See http://www.parliament.wa.gov.au/parliament/pquest.nsf/3b051e205914713c4825718e00186cc2/04f20987e8f9decf4825770e002f821c?OpenDocument .
Also, I’d like to add that the Waterfront Tram could use this clip-on once it was strengthened for regular trains, with scenic views if it is open to the east via a triangular truss instead of a blank steel wall. Imagine a tram from Mission Bay to Takapuna, not just the Marina area as currently proposed. And while we are about it, a tram coming in from Pt Chev and Westmere could also be accommodated, branching to either the CBD or Akoranga / Takapuna. Automatic train control would make all this feasible, interweaving with heavy trains.
The more I’ve reflected on this clip-on beefup idea, the more I think it could be the keystone of a significant PT service and tourism upgrade all round the Waitemata Harbour, possibly with implications as far as Greenhithe and Te Atatu, in addition to Mission Bay and the Shore.
A nice idea but the problem with the current clip-ons is that they are already past their design life and being kept in “just about” service by doing things like resurfacing every year (ripping of off the old asphalt and laying new which helps to glue it all together reasonably well) and banning trucks from those lanes. Those clip-ons are not in a good way and I personally don’t drive on them unless I can absolutely not avoid it. Unless something major is done to them (like ripping them off and putting new better ones on), there’s no way trains will ever run over that bridge. Sadly. If we keep going as we are, one day there’ll be an accident or something that completely blocks both lanes of (or damages) the clip on and it’ll drop off into the sea.
certainly worth a look. But I’m not sure what problem it solves. Will still cost another $4 billion+ for the line to get to Albany.
Although it would be lovely to go from the CBD to Takapuna in 5mins!
I was under the impression the clip-ons will need replacing in 30 years or so, and a new harbour crossing will have to be built then, so it should include rail.
Much better to concentrate on extending busway north to Albany, and figuring out how to handle the PR around reserving a lane across the bridge at peak times for buses!
Would building a new harbour bridge crossing come into the equation?
Quick updates – First to Matt, I think you’re being a bit pessimistic. The clip-ons were built very cheaply to start with and seem to have been too flimsy in hindsight. NZTA has since added 720 tonnes of extra steel to the clip-ons and are no longer panicking. It’s like fixing up an old building to make it earthquake proof. If the worst comes to the worst we can completely rebuild the eastern one piece by piece like grandfather’s axe and that will still be quite cheap, compared to other options for getting trains across.
Second, to Luke, I don’t think it’s going to cost another $4 bn to take the line to Albany, given that Perth ran their trains to Mandurah, as far as Huntly is from Auckland, for A $1.6 billion. We’ve already got a busway that is graded for rail (officially, light rail transit, LRT). As to what problem this link would solve, see my comments re capacity to take Western services, trams, and peds / cyclists all in one go, while future proofing the Shore with rail. There are problems with very high bus volumes in the CBD which suggest that the Northern Busway has to go to some kind of railed system in the future; hence, no doubt, the fact that it was designed for LRT conversion. Whether it would be easy to go to standard heavy rail or whether it would have to be LRT in fact with transfers at Britomart — the station design there also provides additional bays for LRT, currently unused — is something for the consultant to look at. Absolutely the cheapest scenario is that we don’t bother with heavy rail and just run harbour trams and LRT. So I guess we could call a Britomart-transfer LRT system (plus trams) Option B, with full integration into heavy rail (plus trams) as the somewhat more expensive Option A. How much more expensive, we don’t know yet.
Third, to Brisurbane, the point of this in the context of an additional harbour crossing is to stave off having to spend another $4 bn for as long as possible, say 2100 AD. There are a lot of people pushing ambitious projects such as road tunnels or the Anzac bridge scheme http://www.bridge2015.org.nz/, either to increase capacity or to replace the old bridge, but we need to prioritise the Britomart tunnel link before we start talking about spending billions on another harbour crossing from scratch. Also, the old central part of the AHB is in some ways historic as the last hot-riveted bridge anywhere I believe, and if so there’s not much chance of it getting pulled down to make way for a new bridge (just needs to be painted some other colour than grey to look better). BTW thanks for the reference to Mrs Ros MacKinlay.
The immediate problem would be replacing the clip-on, which would mean taking two lanes out of action for maybe a year or more. These will need replacing/decomissioning fairly soon which is the reason for the push for a second harbour crossing: they basically need additional capacity across the harbour to allow bridge capacity to be reduced for an extended period of time.
Secondly, I just don’t think any amount of fiddling with the numbers would overcome the grade issues. Even with only 45m to clear at the main point, we would be talking about a sustained grade of 1 in 40 over 1.8 kilometres either side, or a rail crossing that is effectively 3.6km long. Effectively this would mean a viaduct starting in the vicinity of Victoria park and climbing steadily all the way through St Marys Bay, likewise on the other side we would need a viaduct that didn’t reach ground level until about Onewa Rd interchange. the urban design implications of such a structure are frightening.
I think the options here are quite straight forward, improve bus capacity over the existing bridge in the short to medium term, then build a new railway crossing (probably tunnel) in the long term. It would certainly be a much more realistic proposition to recover two lanes for bus-only use, or to extend the clip-ons with bus lanes.
Estimates of $4 billion + for heavy rail on the Shore are simply ludicrous, they are based on assuming a max grade anywhere of 1 in 50… which results in almost the whole route to Albany being a bored tunnel. In reality the Auckland CBD tunnel and new EMUs will be designed around a max sustained grade of 1 in 40 with limited sections of up to 1 in 33. With these constraints the busway only needs one short tunnel or cut between Sunnynook and Constellation stations and the rebuilding of the Tristram ave viaduct to take heavy rail.
I definitely agree the bridge should be painted something other than grey, I actually started a Facebook group on the topic (I like the idea of a nice golden bronze colour, with bluestone facings on the piers and a bit of feature lighting…).
What if you eased the gradient by bringing it down in Point Erin and at Northcote then cut and cover the tunnels under Queen Street on the north side and under Curren Street on the south side? That by my calculations would give you a gradient of 7%. However I imagine all sorts of issues with this and I don’t know if it would be worth it. Things would have to get pretty dire before I would even consider this a valid option. I agree, stick with buses for now and do it right later on.
It definitely needs a lighting upgrade – the current situation is dire. Its currently got lighting no better than the main road of any town centre. It needs lighting to showcase its form at night like (dare I say it), The Sydney harbour bridge. In fact, I read somewhere its getting a lighting boost for RWC…..
Overall, you can’t get away from the fact we will need a second crossing eventually, and its going to be cheaper the sooner we build it. Putting lipstick on a pig (i.e. adding to the existing bridge) is wasting more money in the face of the inevitable.
Leave the existing bridge for private cars (reduced lanes), buses, cycling and walking. Build a new tunnel primarily for rail, and for other uses if able.
Two distinctly different bridges within view of each other will look silly. There is a proposal to demolish the bridge and sell land where the bridge currently starts/finishes to fund a new, modern bridge. That might stack up, but the bridge will never be demolished.
My preference is to actually flag the rail tunnel for now and build a six lane tolled motorway tunnel from Onewa Interchange to Spaghetti Junction to allow SH1 to bypass the CBD entirely. While this may sound a little road-centric, the end result would be functionally equivalent to building a crossing just for buses, cyclists and pedestrians.
With a motorway bypass in place the existing bridge could have it’s motorway designation lifted and it’s lanes re-allocated i.e. four ‘local’ expressway lanes linking the Shore with the CBD, two dedicated full time bus lanes, and a two way cycleway on one side and a two way footpath on the other. Converting the clip on lanes for general/heavy traffic to buses and cyclists/pedestrains would slash the loading on the strucutres, meaning the would last much longer.
Furthermore, the existing corridor from Onewa Rd to Fanshawe St could be scaled back to just the four ‘local’ lanes and two bus lanes. So instead of an eleven lane motorway through St Marys Bay, the area could be rehabilitated with a six lane boulevard with planting, a local park, a cycle path, a promenade along the watefront etc. It could become the western equivalent of Tamaki Drive. On the other side of the bridge scaling the corridor down to just four lanes and the busway would mean a lot less land required in the Stafford Rd area, in fact their would be plenty of room for a new busway station there plus even a waterfront ToD village.
Also with a motorway bypass in place the Victoria Park viaduct becomes superfluous and could be torn down, while the Victoria Park tunnel could be utilised to provide one lane each way betweeen the bridge and Cook St. The sum effect of this would be no motorway at all on the western side of the CBD north of Spaghetti junction!
So a six lane tolled motorway tunnel gets us: a SH1 bypass a ‘local’ road crossing and separation of local and strategic links, dedicated busway lanes right into the CBD, a superior width cycle crossing, a wide-as pedestrain crossing, the reconstruction of the St Mary’s Bay watefront into something really nice, the demolition of the viaduct across Victoria Park, plus the removal of any surfact motorway north of Wellington St, reconnecting Freemans Bay with the CBD.
Here is a naff picture I did of the bridge painted:
http://a4.sphotos.ak.fbcdn.net/photos-ak-ash1/v200/35/59/553291257/n553291257_545021_48.jpg
Yeah but it’s still $4 billion that could otherwise build rail to the airport and the southeast line. Traffic on the harbour birdge is falling as more employment is located on the North Shore and as the busway becomes more and more popular.
Why waste $4 billion on an unnecessary road tunnel when there are so many pressing rail projects around the region.
The government seems to envisage building the road tunnel at the same time as the CBD rail tunnel (ie. after the RoNS are done) so these projects could still yet compete against each other.
Of course this needs to be weighted up against other funding priorities, but I will make a couple of points:
1) I’m being ‘realistic’ here and assuming that a highway tunnel will probably be built regardless of traffic volumes, at least as long as Mr Joyce is in power. So leveraging other benefits off that might be the only viable way forward.
2) $4 billion was the indicative cost of both the motorway and rail tunnels. Without the rail tunnels the indicative cost was $2.5 billion. Furthermore such a tunnel could generate a very large amount of toll revenue which would offset the construction costsm or at least allow it to be built outside of regular funding sources (i.e. a PPP).
3) I don’t see rail to the Shore being a priority during the sort of timeframes they are talking about for the harbour crossing, especially if the underused busway can be de-constrained at the city end. Indeed ‘saving’ $1.5 billion on the unecessary rail tunnels to the Shore could very well pay for an airport or Botany line instead (if we assume that a road tunnel is built come hell or high water, obviously saving $2.5 billion on the road tunnel would be even better!).
4) Rather than thinking of it as “just more motorway lanes”, it can be thought of as (effectively) building a new crossing for rapid transit, cycling, walking and local traffic… plus removing state highway traffic from the central area, removing the eleven lane motorway from St Marys Bay and Northcote point and rehabilitating both waterfronts, getting the motorway out of Victoria Park and generally removing the barrier down the west side of the CBD.
Basically it removes the ghastly motorway from one side of our CBD, a premier park and stretch of foreshore and hides it undergound in a tunnel, while at the same time extending rapid transit, cycling and walking from the Shore to the CBD… and a large chunk of the cost of all this paid for by tolls on car drivers.
“and build a six lane tolled motorway tunnel from Onewa Interchange to Spaghetti Junction to allow SH1 to bypass the CBD entirely”
Brilliant plan and you could pay for a chunk of it by selling land along St Marys Bay for apartments if you wanted to add them to your suggested mix of development.
But I’d avoid funneling extra road bandwidth in to the north west side of the CMJ. Is there any reason the tunnel shouldn’t route further to the east and then join it up to the SH16 gully? That would mean that north-south traffic could bypass the CMJ completely. Also that would lead the tunnel under a couple of peninsulas that could be used for ventilation, emergency access, and to help construction.
That was NZTA’s second best option, the main thing holding it back was cost. The extra tunnel length to get across to Grafton Gully added about a billion bucks to the estimate. Plus I’m not sure how much more of a ‘bypass’ it would actually be to feed all that extra traffic into Grafton Gully. Southbound traffic would only skip the the city and Symonds St ramps (the first of which has a dedicated lane anyway, so no real gain), but you would presumably have to rebuild the links through Grafton side of the CMJ to accomodate this anyway, at the same time as making some of the existing links on the west side redundant. Furthermore the traffic headed to the Northwestern and Southwestern would still have to funnel through the CMJ (just the other way through).
Not sure if there is much net benefit in swapping through traffic from the west of the CBD to the east.
This is a common argument of the ANZAC bridge group, that we could sell off the land around St Marys bay that is freed up but the problem with that is I can’t see the locals allowing that to go ahead. They will fully support downsizing the road as they already want more parkland around there but as soon as it comes to building apartments, especially ones that may impede their view then it will end up going through the courts for years and they have deep enough pockets to win it. Yes the buildings could be done lower but then they probably won’t be valuable enough to offset the costs like is currently claimed.
Ngati Whatua also might have something to say about that.
I sadly have to agree with Nick R that the proposal is very unlikely to be workable without both a complete rework of the clip-ons AND approach viaducts which will never see the light of consent. It would basically mean an elevated structure climbing upwards to the bridge along the Westhaven/St Mary’s Bay shoreline, and if you want to see some spririted and well-financed opposition, you’ll find it in places like that.
But even if one did that, I presume that running trains within/under the clip-ons would not be as simple, even with re-built clip-ons, because the car lanes above them do not conform to the train’s gradients underneath. And you can’t flatten them out without the car lanes on top and the car approach ramps also have to be re-graded. In total, we are starting to get into a whole new structure, rather than a retrofit.
Finally, rebuilding the clip-on without closing it would conceivably be possible, but would add loads to construction costs.
Sorry for being a nay-sayer, but I don’t think this is feasible enough to be taken forward. Maybe in an environment where trains where our only option to retain mobility – but not in the current climate. And with “current climate” I am for once not thinking of Steven Joyce and Co – I think their Labour opposites would not think THAT much different that they would consider such a scheme with so many potential consent and design issues.
I see an alternative here. The cost of rail will probably be lower, because you already have a busway there, and the greatest costs for a transport project would seem to the acquisition and construction of the right-of-way (which you already have).
The second thing is the gradients and curves. Instead of running standard trains, perhaps running a light metro rail system such as Vancouver’s Skytrain would be worthwhile. They can be automated (so nobody driving the train- massive reduction in cost to operate), which means you can get a long span of high frequency, even late at night and in the evenings. The trains are relatively short (50-100m) so they will fit nicely at existing busway stations. The trains also handle steeper grades and curves much better I am led to believe.
The manufacturer claims that this “medium capacity system” can handle 15 000 – 30 000 passengers/hour/direction, which should be plenty of capacity.
Here is a link to Wiki on ART. http://en.wikipedia.org/wiki/Bombardier_Advanced_Rapid_Transit
My own modest proposal is to reallocate one of the bridge’s clip-ons (probably the southbound) to the busway – given around 1 in 3 people in the peak periods cross the bridge by bus, allocating them 1/4 of the roadspace is surely fair.
Apart from a slight reconfiguration of the ramps at Onewa and Shelly Beach/Curran, and some widening and addition of medians, there would hardly be any work to do to get it up and running. Obviously, it would need to slightly more determined leadership than what we have in place at the moment, and wouldn’t do anything on the cycle and walking access.
Not sure what grade ART can handle but if it wasn’t enough, it would also be possible to use a rubber tyred metro capable of 13% grade, http://en.wikipedia.org/wiki/Rubber-tyred_metro, to climb up to approximately the hight of the Shelley Beach offramp using the bus lane on Fanshawe Street, and then insert itself into the clip on.
Ingolfson refers, I think, to a problem with the abrupt change of grade at the very top of the navigation span. Of course at 45/55 height it will be a bit less, but having the trains inside the clip on enables it to be reduced much further. There is a 10m internal height to play with, i.e. 5m free play up and down to smooth things out, which of course would not be possible if the trains ran on top as cars etc do. So halfway up, the trains would be near the top of the clip-on, but then they would level off and go over the hump gradually.
An advantage of a technology capable of handling steep grades is that it could be fearlessly extended into Northland’s gnarly terrain as a commmuter / tourism / scenic route. It might be possible to follow a highly coastal alignment over farmland and mud flats, taking in all the major holiday / lifestyle destinations, all the way up to Whangarei, making use of hillclimbing capability whenever there’s a hill in the way (e.g. Pakiri) or wherever it’s necessary to go round something. And of course the views from on top would be great. This would future proof Auckland’s major tourism and holiday axis, as I also worry about the feasibility of getting in and out of Auckland once we hit 2 million. I just don’t think the holiday highway’s the answer. Indeed, extension of a North Shore metro could appeal to the constituency that currently supports the HH.
In a similar vein, there would be no technical problem extending a 13% grade techology around the Upper Harbour, or even out to Piha.
To Miggle, there is a peak period bus lane currently southbound on the eastern clip on, but there are reasons for thinking a bit more long term as well. As you note there’s no cycling / walking lane, and to put one on means some more hacking about with the clip on to widen it, so we might as well try and achieve everything at once if we are going to do that.
I think the question there is whether something like light-metro or rubber tyred metro is really that much superior to good old rubber tyred bus to justify the expense. I would imagine that the capacity and speed gains of going to a heavy rail metro/train system would justify the cost in the longer term, but probably not any time too soon.
It depends on what type of cost.
It is easy to look at upfront capital costs, but there are also operating costs and thus lifecycle costs that need to be taken into account.
Then there are benefits from higher frequency at all hours of the day and night.
One of the larger costs is acquisition and construction of the guideway- but with the busway already there, this cost has already (mostly) been taken care of.
The advantage of light metro is that it can be automated (like Vancouver skytrain). So even late on Sunday night you can run services every 5 minutes if you wanted to.
And as we saw in the B.line and BUZ posts, high frequency is important for patronage.
Human Transit did a post about this a while ago: http://www.humantransit.org/2010/02/driverless-rapid-transit-why-it-matters.html
The manufacturer’s website claims it can handle curves and grades, but doesn’t give a figure.
http://www.bombardier.com/en/transportation/products-services/transportation-systems/driverless-systems/advanced-rapid-transit–art-/vancouver–canada?docID=0901260d8000a7a8#