Last week I highlighted an update from AT on Light Rail. In addition to that they also gave an update on rail to Mangere and the airport including their consideration of using light or heavy rail for the project. Once again I wasn’t at the presentation personally so can only go off the slides shown.
Firstly one thing I do think is good is that AT on their website are calling Airport and Mangere Rail. To me that’s a much better description of the project than just airport rail as this project will serve a much wider community than just the airport which is one of the reasons it’s worthwhile doing.
As for where the project is at. The strategic assessment already undertaken has shown that rail is the most effective long term solution and a scheme assessment has determined a rough footprint which would require the purchase of 218 residential and 17 commercial properties. They estimate the project would cost around $1.4 billion to get to the airport from Onehunga. The engineers have been looking at ways to cut the cost of the project and two points are noted.
- They’ve estimated the cost of double tracking the Onehunga branch line at $400-$600 million. For that price it sounds like they’re effectively suggesting trenching the whole line – presumably to remove all of the level crossings.
- Put the rail alignment down the centre of the motorway. I don’t know what the original alignment was but I wonder if it crossed the motorway a few times to give better coverage of the community.
By building the route as light rail they believe it could be done cheaper for similar benefits and so they’re comparing the two modes.
They appear to be looking primarily at how to provide a single seat journey from the airport the city centre with the two options shown below along with a comparison between the two.
I have some serious concerns about this analysis as AT seem infatuated by light rail at the moment so it seems to me they’ve in effect stacked the deck against heavy rail. Here’s why
- The light rail option is an extension of line that doesn’t even exist yet and there’s no guarantee it ever will.
- I also wonder how practical that alignment alongside SH20 is. I know Light Rail can climb hills better than Heavy rail can but that route would be one long, steep and slow climb if it’s even possible.
- When the measurement of success seems to be based on how many people could walk to a station and catch a train then having the heavy rail option with fewer stations it’s no surprise it has a lower result. It seems to me silly not to at least have a heavy rail station around the Montgomerie Rd area which is only about 2km from Mangere and 2.5km from the airport. Other stations may be able to be justified.
- It’s no surprise that the Light Rail option has more people within walking distance of a station as it travels right through the densest residential area in Auckland – the CBD. I’m not sure if AT’s heard but there’s a heavy rail project which does that too – it’s called the City Rail Link. What’s more AT’s planned operating pattern will see trains from the western line pass through the CRL before heading towards Onehunga. It seems like there’s a bit of gerrymandering going on this. If AT are talking about delivering single seat rides then they should also include all the people next to the western line, even just the people near the inner west and CRL stations add almost an extra 60k to the walking catchment.
- With a dedicated corridor between Onehunga and the airport the travel time of light and heavy rail is not likely to be all that different. The issue comes in north of Onehunga. AT say above the extension just from Dominion Rd will have 1.9km of slow on street running, what’s not also mentioned is the on street running on the Dominion Rd corridor through to the city. The next slide looks at exactly this issue and it is perhaps the biggest argument against light rail. A 35-38 minute travel time is very competitive with all other modes at all times of the day whereas light rail is barely faster than the existing airport bus. It’s also worth contrasting this approach to what happens elsewhere in transport. As a society seem to be prepared to fork out billions with few questions to obtain a few minutes of travel time saving on roads the same but for rail it’s all about how we can do things on the cheap.
Next we have a bit of a matrix comparing many of the things mentioned above including what I consider to be flaws in many of them. One thing I haven’t mentioned is the frequency of service. This is something completely within AT’s control of how they run the rail network.
The next few images show cross sections the proposed rail alignment down the centre of the motorway and through the Kirkbride trench. The car lanes would be pushed out to create enough space.
Lastly this image shows an elevated section soaring above the Kirikbride interchange. My understanding is that both options of through or over the trench are possible and are both still being considered.the chosen mode will go over or through the trench so both options are being considered.
It’s good to see some details on this even though I’m not convinced by the analysis done to date.