Opinion: Dual-mode electric-diesel locos - KiwiRail's missing option

The Raurimu Spiral, a series of curves and tunnels that drops trains from the Central Plateau into the King Country, is ...
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The Raurimu Spiral, a series of curves and tunnels that drops trains from the Central Plateau into the King Country, is on the electrified part of the North Island Main Trunk Line.

OPINION:  Following a request for KiwiRail board papers on the decision to replace the 30-year-old electric locomotives on the North Island Main Trunk (NIMT) with diesel locomotives, we received a heavily redacted copy of KiwiRail's "Better Business Case: NIMT Performance Improvement" late last year.

The NIMT is electrified between Te Rapa (just north of Hamilton) and Palmerston North only.

The route is serviced by diesel locomotives from Auckland/Tauranga to Hamilton, by electric locomotives from Hamilton to Palmerston North, and by diesel locomotives from Palmerston North to Wellington.

A European-designed Bombardier (dual-mode electric and diesel) locomotive, manufactured for Indian Railways.
supplied

A European-designed Bombardier (dual-mode electric and diesel) locomotive, manufactured for Indian Railways.

The requirement to change locomotives at Hamilton and Palmerston North is said to add about 1.5 hours to the transit time (although a lot of freight trains have to stop at Hamilton and Palmerston North for re-marshalling wagons anyway).

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The KiwiRail board's position is that replacing electric locomotives with diesel locomotives would improve rail freight transport on-time performance between Auckland and Christchurch, and so achieve modal shift of freight from road to rail transport.

KiwiRail considered four options: 1) diesel locomotives from Auckland to Wellington; 2) new electric locomotives from Hamilton to Palmerston North plus diesels; 3) second-hand electric locomotives from Hamilton to Palmerston North plus diesels; and 4) a mixed fleet of diesels and refurbished electrics via a control system upgrade.

The third and fourth options were eliminated as being too complex. From the first two options, diesel locomotives from Auckland to Wellington were chosen.

The analysis found the lower capital costs of diesels more than offset the lower operating and maintenance costs of the electric locomotives.

An option not considered by KiwiRail was dual-mode locomotives. These are driven by electric motors powered by either the onboard diesel-powered generator, or the overhead electric wires where the route is electrified. They have been operating successfully, or are planned to, in the United States, Canada, China, India, Britain, Poland, Italy, Spain and South Africa.

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They would have all the benefits of one locomotive from Auckland to Wellington, but with electric traction from Hamilton to Palmerston North.

The cost of European-designed Bombardier dual-mode locomotives is NZ$7 million to $8m each. That is approximately 50 per cent more than the cost of a new diesel locomotive.

However, the lower operating and maintenance costs of the electric-mode will more than recover that capital cost difference. And because the diesel-mode will only be used for the beginning and end of the journey, the diesel components will have a much longer life than a diesel locomotive.

Automated switching between power sources would solve KiwiRail's concern about the current time delays at Hamilton and Palmerston North. Unlike the proposed new diesels, they would avoid greenhouse gas and noxious emissions for the electrified part of the route, because 80 per cent of New Zealand's electricity is generated from renewable resources. This is an option that must be considered.

The best long-term solution would be completion of the electrification of the NIMT.

The original electrification of the line from Palmerston North to Hamilton was one of the greatest engineering enterprises of the 20th century. Engineers in Railways, Electricity, and Public Works Departments widened rail tracks, strengthened bridges and enlarged tunnels or made open cuttings.

Now the two ends – Auckland to Hamilton, and Wellington to Palmerston North – need to be completed.

Compared to the mountainous central region, these sections are straight forward.

Also, some lines near Wellington and Auckland are already electrified for metropolitan rail services, although the electrical capacity will need to be upgraded on the Wellington suburban line to Waikanae to also accommodate freight trains.

Once the entire NIMT is electrified, the dual-mode locos would be able to run on electrics for the whole journey.

The chief executive of KiwiRail claims that the cost of electrifying the remainder of the NIMT is $1 billion, and that to electrify the entire North Island would cost more than $4 billion. Funding would be a matter for government, if it considers this a priority for land transport funding.

There is no evidence that this option has been considered. KiwiRail has merely allowed for future electrification of the NIMT by agreeing to leave the electric lines in place.

KiwiRail has considered its best commercial interests as a state owned enterprise (SoE). However, a switch from electric locos to diesel locos on the NIMT will increase greenhouse gas emissions, which goes against New Zealand's commitments under the Paris Agreement on Climate Change of December 2015.

KiwiRail says there will be a net reduction in greenhouse gas emissions through a mode shift of freight from road to rail, if a faster, more reliable service is provided by new diesels than the current 30-year-old electric locomotives. But similar mode shift benefits could be expected from new electric locomotives, or dual-mode locomotives.

If the Government is serious about tackling climate change, it must take the lead on national interest issues.

Dr Roger Blakeley is a former Secretary for the Environment, Keith Flinders is an electrical services consultant, Alex Gray is a senior project manager and Bob Norman is a former Commissioner of Works.

 - The Dominion Post

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