Recently the government announced the next steps for light rail in Auckland, the creation of an Establishment Unit to come up with a recommendation of what to build before the end of the year. A few weeks ago former Chief Executive of Manukau City Council, Leigh Auton, was appointed as the chair for the Establishment Unit.
As also explained at the time of the announcement, as well as a stakeholder event on Friday, there are essentially two key trade-offs/decisions that need to be made.
- The Mode – a surface based light rail solution or a fully grade separated light-metro one.
- The Route through the isthmus – either Dominion Rd as initially envisaged or Sandringham Rd, which has been suggested as there is a huge amount of Kāinga Ora land at the southern end which could enable the government to tie in its house building programme.
If the unit is to succeed in its remit in making the best recommendation, as well as getting buy in from Aucklanders, one thing I think is critical is that they compare the best iterations of each of those trade-offs.
For example, my understanding is that after taking over the light rail project, Waka Kotahi came up with new route options through Mangere that ‘wiggled’ all over the place in order to serve Kāinga Ora land but that came at the expense of directness and speed. While we’re probably one of the first to say that speed to the airport isn’t the primary purpose of light rail, it shouldn’t be ignored either. That change also likely contributed towards the NZ Super Fund’s light-metro style proposal looking more appealing to the government, the investigation of which ultimately derailed the whole project and has now resulted in this new process.
Perhaps put another way, the Establishment Unit need to ensure they undertake as fair a comparison as possible. Comparing a direct metro solution to a wiggly local bus route on steel wheels is not even comparing apples with oranges, at least they’re both different kinds of fruit.
I also think that if we’re really talking about a fair comparison, perhaps we should also consider what we could get for equivalent priced networks. It’s surely not too much to expect a metro style solution to perform better than a surface one, after all, it is likely to cost 2-3 times as much. But a question I’ve been thinking about a bit recently is, what if we took that price difference and made a bigger surface network, would the metro solution perform better than that combined network?
That led to the question, just how much more surface network could we get for the cost of a single light metro line?
So that’s what I thought I’d focus this post on. I’ve also included a couple of assumptions.
- For this post I’m going to assume the cost of the 14.3km Mt Roskill to Airport section is the same regardless of mode – even though light metro would need more expensive signalling and likely a more expensive route through Onehunga not to mention having to deal with the basalt through the isthmus.
- I’m also going to assume that light rail would run from Customs St to Mt Roskill via Dominion Rd and that Light Metro would run largely the same route except starting from Wellesley St under the Aotea CRL station. These routes have the same distance.
To start with answering the question, we need to get a better handle of the costs of each option. So I looked around the world at some similar projects. In all cases I’ve roughly adjusted for inflation and converted costs to NZ dollars. Some of the projects are yet to start construction so I’ve used the latest estimates I could find.
Light rail projects seem to vary from just over $60 million per km, such as Canberra’s, which was largely built in the middle of a wide grassed median, up to around $200 million in Sydney and some North American lines. In Sydney’s case the high costs seem to be due to a significant amount of services to move and substantial public realm upgrades while the North American examples tend to have a lot more tunnel and/or elevated sections in places. For the purposes of this post, I’ll use a figure of $150 million per km.
The costs here tend to have more variation, though I’ve also included projects that might look like or even be part of light rail systems but the projects themselves are fully grade separated. For example Ottawa’s light rail line uses street style light rail vehicles but on a fully grade separated route, its costs are likely helped in part because it largely converted an existing busway corridor. In the case of Seattle, after their initial line, which has a substantial section of on-street running, all subsequent extensions have been fully grade separated more like a metro line. At the top end of the spectrum, Honolulu’s fully elevated Light Metro system has suffered many cost and time blowouts and is now estimated to come in at over $500 million per km while Vancouver’s Broadway Subway project is expected to start construction this year and is costing nearly $600 million per km.
In an Auckland project I think we can expect costs at the upper end of this range. This is because the isthmus section will likely need to be entirely tunnelled – good luck getting an elevated route past locals easily. We’ve also seen with the City Rail Link that digging a tunnel through the city centre is expensive (over $1b per km), in part we’re competing for talent and resources with many other cities, especially those across the ditch, also looking to build similar mega-projects. A metro solution would also require a ‘CRL 2’. As such, for the purposes of this post I’ll use a cost of $550 million
Based on all of this, the City to Mt Roskill section would cost:
- Light rail – $1.2 billion
- Light metro – $4.3 billion
A light metro solution is over three and a half times the cost.
The Extra Network
The figures above suggest a light metro network would cost $3.1 billion more than a light metro one – though as we’ve discussed before performance wouldn’t be all that different. At the light rail figure of $150 million per km that suggests we could get about an additional 21km of surface level light rail, though possibly more as we’ll already have infrastructure like a depot. That’s at least a whole other light rail line. So what could we get for that.
The first and most obvious option to spend that budget on would be the Northwest to at least Westgate. From a junction somewhere around Ian McKinnon Dr it is about 16.5km to Westgate. The big unknown is just how we’ll get across the causeway, can we take some motorway lanes (freeing up the bus shoulders for other purposes) or will we need something much more infrastructure intensive?
We’ll also likely want to extend service from the bottom of Queen St to Wynyard as per the original AT plans. This would add about 1.8km leaving us with about 2.7km from our budget which could be used to extend the Northwest line closer to Kumeu, say to a station at Brigham Creek.
Is a single metro line really going to deliver better outcomes for Auckland than, for the same cost, also serving the Northwest?
As mentioned, the biggest concern is getting over the causeway, so if that is an issue, here’s another option.
We’ll keep the Wynyard extension from above. To that we could add our Crosstown Light Rail idea. With a short 4.4km extension from Dominion Rd to Avondale we could open up much easier west to Onehunga/Mangere/Airport trips. It also helps in serving that Kāinga Ora land with a quick transfer to the city via either the Western Line or Dominion Rd line.
But we could go further and also and convert the Onehunga Branch (3.4km) to light rail, improving service on it compared to what exists today and further enhancing the crosstown nature of the route. This would leave us with 11.4km in our budget.
The government are placing a lot of weight on serving the Kāinga Ora land in Wesley, which is why Sandringham Rd is being considered. If serving that land/corridor is so important we could always also build a line there. It is only an extra 5km to get as far as SH20. Add in Mt Eden Rd and that’s three of the busiest isthmus bus routes served as well as a crosstown RTN connection.
There are of course plenty of other routes and uses that could be considered and that extra money would go a long way making many other public transport improvements around the region. For example, I’d love to see us getting at least some interim services on other planned rapid transit routes, such as Upper Harbour and/or extending the Airport to Botany route past it’s currently planned terminus of Manukau.
Ultimately, even if a metro network performs best for the City Centre to Mangere route I just can’t see it staking up compared to a more greatly expanded rapid transit network.
One final thing worth noting from looking at this, is construction time as disruption is already a major concern for some. The initial 13km stage of the Gold Coast’s light rail line took just two years to build, Canberra’s only about three years and even Sydney’s beleaguered project just over four years to build 12km.
By comparison many of these metro style systems tend to take a lot longer, for example the 15km Copenhagen City Circle Line took a decade to complete, a timeframe that appears not that uncommon. Meanwhile the Honolulu project started construction in 2011 and earlier this year they said it might still take another decade to complete. We only need to look at the eight years of disruption the CRL is imposing to know that we can expect at least the same again for any tunnelled solution.