At about the same time as Wellington were announcing their new battery electric regional trains, KiwiRail was talking to the Waikato Regional Transport Committee (WRTC) about a plan to effectively electrify the entire North Island rail network.

You can also watch the presentation here, from about 44 minutes on.

When it comes to carbon emissions, rail is already about 70% more efficient than moving freight by truck – and KiwiRail say they’ve already made some good improvements by achieving a 23% reduction in fuel consumption per 1000 gross tonne kilometres over 8 years to June 2021, predominantly “through fuel saving initiatives such as optimising loads and timetables, and driver behaviour modifications“.

They are looking to reduce their emissions further, with a 40% reduction by 2035 and net zero by 2050. Among their reasons for doing this: reducing reliance on imported fuel (and the price volatility associated with that), and the fact that their customers want them to.

Previous work KiwiRail has done on the issue highlighted that focusing on the Golden Triangle – the Auckland to Tauranga corridor – was the best place to start, as it’s the busiest part of the freight rail network. Investing in the busiest areas is also suggested in the heavily roading-focused Government Policy Statement on Land Transport.

Investments in rail should be focused on the busiest and most productive parts of the existing rail network, to support efficient movement of freight. This will complement investment in our state highway network to deliver a productive and efficient supply chain.

KiwiRail’s previous work also found that a form of electrification was the best way to go, over other options like hydrogen. That work has fed in to the Golden Triangle Electrification Programme (GTEP) Detailed Business Case. On Monday, KiwiRail told the WRTC quite a bit of work has been done on this so far, including looking at expected demands, operational options and timetables.

They said that work has already revealed options for improving their network capacity even without electrification:

“One of the main reveals out of that is that the network has a lot of capacity that can be utilised today, so without much more investment in infrastructure. So things like the single line section through the Whangamarino wetland, for example, with some minor enhancements to the signalling you wouldn’t need to double track all that way to create even more capacity than it’s got at the moment.”

Later in the discussion, KiwiRail gave a bit more detail about what is involved with Whangamarino section – which is about 12km long, and the only significant section of single track line between Auckland and Hamilton.

They said that more capacity could be created by slightly lengthening the passing loop in the middle and upgrading the signalling to allow for high-speed arrivals and departures and to simultaneously berth – which is the ability to have trains enter the swamp at about the same time from each end. This is something not possible with the existing signalling system, which dates from the 1960s. Elsewhere, more capacity could come from improvements like new or lengthened passing loops.

KiwiRail’s likely option

Much like the Wellington Regional trains, KiwiRail’s likely solution is to make use of batteries to be able to run off-wire. They noted a lot of work in the business case has been on figuring out just how much transformer and battery equipment could fit on a locomotive, and how to optimise that for our network.

Interestingly, under all scenarios they considered, KiwiRail sees the need to install wires between Pukekohe and Hamilton – so this has become a “no-brainer” project to do. Depending on the actual battery capacity of the trains, they might also need to put some wires east of Hamilton too, so that the trains have enough range to reach Tauranga. They are looking quite closely at just how much is needed in order to minimise costs. They also say they prefer electrification at the western end of the line, due to the location of a power grid exit point at Ruakura.

At Tauranga, there would need to be a recharging facility: KiwiRail noted that the 2-4 hours it takes to strip and reload a train is the perfect amount of time to recharge the batteries. They also mentioned that some of the other options they looked at did decarbonise the railway but added heaps of operational complexity and costs – which is one reason the battery option is preferred.

The trains would be able to run all the way to Palmerston North under the wires, so could serve those routes too. KiwiRail explicitly say:

Metro Passenger Electric Multiple Units and Electric Regional and Tourism Passenger trains could operate south of Pukekohe utilising the overhead wires

Running under batteries also removes the often noted constraint of the Kaimai tunnel – i.e. that it needs time to clear the fumes after each diesel train passes through. Solving this would make it much easier to run future passenger services to Tauranga.

It gets better: while the focus of this work is on the Auckland to Tauranga route, KiwiRail has also worked out that with this one class of locomotive and some charging locations at the terminus of lines, they could also serve all of the other feeder lines in the Waikato and Bay of Plenty.

They even say that they’ve got a solution to enable this single class of locomotive to serve all lines across the entire North Island. That would allow them to standardise on a single design of locomotive and ways of operating, which will create additional efficiencies.

This from an earlier study suggests the level of battery capacity needed to serve all routes in the country:

When is it happening?

KiwiRail are still finalising their business case which will confirm the preferred option. Completion of that is expected by the end of this year. They think a further business case is then likely to be needed to nail down the costs, which includes things like which bridges would need to be modified to run wires, and what the preferred option is for each of those.

A big question will of course be if or when this actually gets funded. And, as noted in one of the slides above, once funding is approved it’s likely a 4-5 year process before we see results – so, potentially it’s still quite far away.

We’ll look forward to seeing the actual business case. For now, it looks like KiwiRail has put some great work here and the solution feels like it passes the sniff test. It certainly seems like a far more worthy investment than the current obsession they seem to have with the idea of the Avondale-Southdown Line. It’s also likely far more useful than most of the government’s current obsession with mega-roads.

Combined with the Wellington announcement earlier this week, it does feel like there’s a clear direction for regional passenger services, too. An AC version of those trains could be used to improve the Te Huia service, and then once the wires are installed, it would enable the batteries to be used to extend those services Tauranga.

Let’s hope that KiwiRail can get these next stages completed quickly, and secure the funding needed to get this underway.

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