The Eye of the Fish

June 27, 2013

Auckland Rail Link

Stunning news today in our little northern satellite town of Auckland, where the National government is deciding to go ahead with the CBD Rail Loop Link. That’s a pretty mighty about face for the government, and an excellent outcome for Auckland. It’s also a rather hefty bill, for what Gerry Brownlee still calls a short little loop of rail, but it really is a vital one. The rail loop Link will do several things – connect to Britomart so that trains can run straight through, instead of dead-heading, and hence allowing a much faster turnaround for departures. Much needed, Auckland! It also means that they’ll have to dig up QEII square yet again, demolish the crappy shopping centre there, and dig an almighty great trench up Nelson St for about 5 years, so there will be tears before bedtime from Aucklanders for years, once it eventually gets underway.

But there is one thing. I’ve always had my doubts about whether the route is right. Is it wise to try and get a rail station up to Karangahape Road? If Auckland’s topography is hills and valleys falling down to the waterfront, then is running a route right up a ridge really the best answer? Or would it make more sense to have it running up a gully (like Queen St – that is a simple gully) and then tunnel under the ridges instead?

There is of course one other thing – the inability of Wellington to get its way with a (far more logical) Light Rail system, especially when we are already a city that works well with rail, and Auckland is intrinsically more car-ridden.

27 - 06 - 13

I can’t wait for a similar reversal in Wellington. Actually, I can and expect I will. Maybe if our mayor had ever visited anyone at Govt, things might be different.

Seamonkey Madness
27 - 06 - 13

Although it’s probably been a decision that’s been culminating for months, maybe it was fast-tracked while the vision of Wellington poor, clooged motorways are still fresh in the minds of the nation.

Some 9000 rail commuters were “forced” to take either rail replacement buses (with HUGE queues) or their own cars. This, in some cases, tripled the commute time into Wellington and cost the local economy untold dollars in lost hours (not to mention the early morning flat white trade must have been abysmal).
This must have scared the bejesus out of Gerry & Co, and got them to thinking the could make bonus political capital out it.

Whatever the case, about bloody time! No doubt tomorrows announcement will come with a lot of nasty, rusty hooks attached, but none the AC wouldn’t be willing to swallow in order to get their CRL.

27 - 06 - 13

Great news for Auckland. Were National worried that they were going to end up on the wrong side of a coming election issue…?

I think the reasoning for the route under the ridge is that it actually makes it easier to build, I imagine that the southern half of it will be done using TBMs at sufficient depth that there’s little worry about affecting buildings. While the northern part where it’s shallower is going to be much more disruptive. Also this will provide a more consistent/even slope up to Newmarket. If you went up Queen Street the gradients would get quite large as it swings upwards at the southern end to join with the western line, too large for heavy rail I suspect. Deep bore tunnels are the way of the future in most cities, avoids the disruption and can be done quite cheaply with the right hands in charge as the spanish have proven.

This case of the trains not running in theory would be an amazing way to gather lots of AWESOME data for proving the business case of public transport investment — I wonder if they’ve collected this data? Me thinks not…

27 - 06 - 13

Erentz, I’m about 99.9% sure that they won’t be using a TBM on this project at all – and it won’t be a deep tunnel, but a shallow one, as it needs to connect with the existing Britomart station track levels. That is one of the tragedies of the scheme – Britomart was so poorly thought through in the first place that they have built stairs in line with the end of the tracks, and so they will need to demolish and rebuild the stairs at the glass box anyway. They won’t want to have to rebuild the whole Britomart station however, so the track levels will have to stay the same.

The level of the trains is not that low at Britomart – and TBMs need a large pit created in which to insert the machinery (unless they bring the whole machine in via the lines at Britomart anyway…), but the main thing is that with the train lines not far underground, they will be just below the city services,mwhich are far too sensitive to put a machine through. Plus, I’ve heard that the shopping centre (used to be DownTown, now – is it a Westfield?) is had it, and due for demolition anyway, so they’ll take the opportunity to thread the tunnels through the piles anyway…

Your comment about Light Rail is an interesting one though, as of course the current trains are just carriages hauled by heavy diesel locomotives – about as crude a public transport as you can get (outside of having steam trains). Britomart is the “world’s first diesel underground train station” only because it is such a dumb idea, and they didn’t get their shit together to electrify the rails there first. So, at present, the system is still a Heavy rail system, and I can only hope that Len Brown’s advisors also order some new electric trains, as well as the overhead cabling for it, at the same time…
27 - 06 - 13

It’s definitely using a TBM. It’s cut-and-cover up to Aotea Station on Albert St, and then tunnelled from there to where it meets the western line near Mt Eden.

It’s also not a loop—to call it a loop makes it sound like trains are going to be going around in circles. It’s called the City Rail Link, because it links Britomart with the western line, allowing up to 50 trains per hour and removing the Newmarket bottleneck. Here’s an explanation, and a helpful diagram of how trains are likely to run through the station:

28 - 06 - 13

I was getting excited about a revolution, but this is a dirty trick by National, bribe Aucklanders so you can ram through more roading projects, including a second a harbour bridge/tunnel. The CRL has a start date of 2020, while you can bet they’ll get cracking a lot sooner on the motorways.

28 - 06 - 13

Thanks non-residual, I’ll make sure to call it a Link in the future, not a Loop. You guys have got a few Links up there in Auckland – City Link, The Link, Bus Link, Blue Link, etc. popular word. I’d call the new thing a Loop, myself, just to differentiate it – but we’ll try to do as you recommend and Link it.

Re the TBM – yes, I am right about the downtown digging – cut and cover is the only way to make sense of that spiders web of tangled services in the ground around the downtown area, just a few feet below the earth – and already into the tidal zone. It’s going to be a bitch to dig! But about your assertion that it will be a TBM in the upper reaches – hmmm, I’m still not convinced. How many projects have you worked on with TBMs? More than zero? There are certain situations where they are good, and others where they are pointless. Although my money would be on a road-header to tackle the volcanic rock of Auckland, it will be great if NZ does have the desire to purchase a full TBM sized for rail tunnels. We’ve got a few projects that we could use it for down here in Wellington as well…

And Sav – I don’t think it’s a dirty trick at all. If the government wants to waste our money on roads, let them do it. As long as there is a protected route of public transit as an alternative, getting more traffic into a city and choking it up just works to the advantage of a rail system. That’s the key you see – congestion REALLY forces people to take alternative means of transport – but only if the city is really congested. Just a little congested isn’t enough – it needs to be stuffed to the gills, then everyone flocks to the trains instead. So- all good!

28 - 06 - 13

Erentz is right about the gradient at the southern end, see the gradient graphic in this post – this also shows the portion to be cut and cover vs TBM.

Transportblog really is required reading for any information about this project (it’s second on my RSS feed after EotF ;) They have worked tirelessly to get the key messages across which AT and mainstream media have really failed at.

We can only hope that this new found pragmatism for rail projects can extend to our own spine study now…
28 - 06 - 13

I’ve worked on precisely zero projects involving TBMs, but the tunnel is 40m deep under Newton, so there’s not really any other way to do it.

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30 - 06 - 13

The Auckland trains do look nice. There were some really crappy design elements of the Matangi’s – I was really shocked by the raised access panels on the floor of the entranceways making the floor inlevel. I’ve never seen anything like that on any other train I’ve been on. Seriously shabby

Max: you may be right about the TBMs. It is definitely deep for the southern section. I assumed (or maybe read somewhere) TBMs were the way they were doing that part as its deep, it’s twin bore tunnels, and thats they way they decided to do waterview connection.

30 - 06 - 13

Non-residual, actually, it’s not the depth underground that dictates the need for a TBM at all. Sorry to bore you if you’re not interested – I’m fascinated by TBMs and so have been reading up on them for years, as well as talking to a friend who worked with them in London. The thing is, they are very long machines, and need a train track full of equipment tacked on behind themselves. So you need to dig a massive hole to get them into the starting position. They can, if they are clever, be bought to operate in what is called a Earth Pressure Balanced mode, which basically means it can go through watery soil, which is great often when deep underground. If they were going to bore the hole for the second Auckland Harbour crossing, for instance, they would need to use EPB TBMs without a doubt (but my guess is that they will use precast sections instead, lowered into the Harbour, and then effectively glued together underwater. They did the Harbour crossings in Sydney and Hong Kong like that, or so I believe).

But the issue in Auckland’s terrain is that they will have to start off Cut and Cover as they go from Britomart, under the QE2 square, under DownTown shops (with careful coordination over the position of the foundations for the new building), and then probably also C&C as they go up Nelson St, and then, as the Transport Blog graphic shows, it goes in a “bored tunnel”. Please note – bored does not necessarily mean bored with a TBM. My argument is that it could be better with a road header as they cost a helluva lot less, and are often used when digging through rock. Seeing as Auckland is all just one great big blamange of dried up lava, there is bound to be a lot of dusty rock to dig through. Once the hole is dug, shotcrete concrete is applied, and you move on. I’d be keen as mustard for them to buy a TBM or two, but you know, seeing as how NZ likes to do things on the cheap…

Anyway, that’s all splitting hairs and is neither here nor there. Its all quite exciting really! Nothing much happening here – I think I might move to Auckland – when this goes ahead!

Matt L
4 - 07 - 13

Just to correct a few points on here

The CRL will be cut and covered up Albert St (not Nelson) and this is because of how shallow the tunnel is at this point plus to get around the below ground infrastructure. The Aotea station (between Victoria and Wellesley St) will also be dug using cut and cover.

The majority of the tunnel between Aotea and Mt Eden will be built using a TBM (7m wide to be exact). While there is definitely volcanic rock to deal with at the Mt Eden end, it is at the surface and throughout Auckland sits on top of a form of sandstone which is actually quite easy to tunnel through.

You mention that NZ does things on the cheap so wouldn’t buy a TBM but we have one arriving in just a couple of weeks to dig the tunnels at Waterview where they had initially planned to use road headers. The TBM is the 10th largest in the world and cost $50m

5 - 07 - 13

Thanks Matt, you run a great blog in Auckland – very useful facility for the city. The info about the Auckland Rail Link is greatly appreciated – where can I read more? For instance, presumably, if we have got just the one TBM for Waterview, it is going to do a tunnel in one direction, then exit, get turned around, and go back to do the other direction? Or are all the cars fitting within the one tunnel? And will we be doing the same for the Rail Link? Or, at 7m, is that wide enough for a track each way? I’m presuming it would be, but that seems a strange approach to me – traditionally, tunnels have only been wide enough for one train at a time, not two of them side by side.

5 - 07 - 13

Don’t know about Auckland, but the single-track Crossrail tunnels in London are being bored by 7.1 m diameter TBMs, for a 6.2 m diameter tunnel. (The London track is a wider gauge than NZ, but the trains are the same size as here – that’s where most of Auckland’s (and all the Wairarapa’s) current trains came from.) Tunnels need to be wide to allow emergency egress along the sides of trains – narrow single-track tunnels (many in Wellington, none in Auckland) are a real pain.

A double-track tunnel would need a much larger TBM and would generate a lot more spoil than two single-track ones (the area of a circle is proportional to its radius squared), so a lot more expensive.

And re Erentz’s comments about the raised access panels, I think he’s referring to the wheelchair ramps. Apparently the reasoning is that since they come out of the floor, there has to be a hole (when in use) or a bump (when folded away), so they’ve gone for a compromise between the two.

Matt L
8 - 07 - 13

Maximus – Thanks for your comments. With both Waterview and the CRL there will be two tunnels, one for each direction. As Mike says, doing it as one massive tunnel means a lot more spoil to remove and therefore more cost. The wideness of the tunnels is to allow for emergency access.

There is a lot more information about it on the Auckland Transport website

and some very detailed reports for the documents supporting the designation process
Including the concept design