KiwiRail has marked a major milestone with its first two DM locomotives completing their trial journeys phase and officially joining the fleet.
The locomotives, which were built in Spain by rollingstock manufacturer Stadler, will operate the route from Christchurch to Timaru on New Zealand’s South Island.
In total, KiwiRail has purchased 66 new DM class locomotives. These will be used for freight transport and will gradually replace the ageing DX fleet, which is 48 years old, on average, and expensive to maintain.
The first two DM locomotives completed their 5000-kilometre trial running period in August, and locomotive engineer training is now being rolled out on the South Island.
KiwiRail’s Chief Metro and Capital Programme Officer David Gordon said the trial journeys were fault and failure free, which is a “huge success for a first-in-class locomotive”.
The modern locomotives even held up well in the challenging Otira to Arthur’s Pass section of the route.
“Extensive simulations and calculations were done prior to the DMs arriving, but it was still reassuring to see them clear all structures and tunnels throughout our South Island network as they are the largest locomotives in our fleet,” Gordon said.
“The current consist of DX locos for the Otira tunnel are in a bank of six and the expectation with the DM is that we will need less than six for the same task.
“But with only two in the country so far, we will need more DMs in the fleet to carry out full testing before we can assess the number required.”
Type testing
Tests during the seven-month testing phase for the DM locomotives included tuning up the traction and braking systems, checking the performance of the locomotives with a load, and checking the compatibility of the DMs with legacy locomotives in the fleet.
Justin Young, mechanical engineer at KiwiRail, said: “Regulatory-wise, the DMs fall into this category where it’s a new vehicle to New Zealand.
“We have to satisfy the regulator, really making sure that they’re doing what the current standards around the world are doing. We’ve done our best to ensure that the locomotives are safe and fit for purpose.”
Young said the first two DMs had to undergo rigorous testing so problems could be ironed out before the rest of the DMs are shipped to New Zealand.
“It’s really easy to fix two locomotives while they’re in New Zealand, but it starts to become a challenge when there’s up to ten locomotives at once,” he explained.
With two different testing teams on different sides of the world, you might think it would be difficult to collaborate – but Young said this was actually quite handy.
“Due to the big time difference between New Zealand and Spain, what we were finding is we could send issues across in the late afternoon and show up the next morning and have some solutions already.”
Stadler made several upgrades to the prototype DMs based on lessons learned during testing, such as changes to the traction system for better hauling performance and engine cooling improvements.
Rectifications were also made to the likes of anti-climbers, cab doors, vigilance software behaviour and engine mounting.
“As expected with a new model locomotive, we did experience some small teething problems, but in the case of the DMs these were minimal,” Gordon added.
The specs
In the Request for Proposal, KiwiRail provided Stadler with a functional/performance-based specification, and Stadler responded with a technical specification to meet those requirements that was revised and updated as testing progressed.
The operator has specified that each new locomotive must have a low emissions profile, meeting the European Union Stage V emission standard with a diesel engine 3000-kilowatt output.
It’s also targeting a 25 per cent reduction in nitrous oxide emissions, and a 30 per cent reduction in particulate matter emissions.
The locomotives must also have an improved traction system design that enables fewer locomotives to do the same work, with a potential reduction of 20 to 25 per cent in carbon dioxide emissions through reduced fuel burn and use of onboard technologies, plus futureproofing for longer and heavier trains.
Dual cabs provide operational flexibility, and the locomotives are also equipped with a Driver Energy Reduction and Advisory System to support the locomotive and drivers to achieve optimal energy performance.
Each locomotive is also equipped with an auto engine start stop (AESS) system which can switch off the engine when the locomotive is idling, saving fuel, as well as a Train Handling System to manage asset fatigue and energy performance.
Meanwhile, a Remote Diagnostic System allows KiwiRail to receive instantaneous fleet geographical location, speed, fuel tank status and battery main switch status, a summary indication of mileage, energy consumption for each locomotive, fault records (automatically logged for each locomotive), locomotive condition and trending of key parameters.
Borja Rozalén Valcuende, Project Technical Leader in Design and Development Engineering at Stadler, said it was at times challenging to achieve KiwiRail’s expectations, but he is proud of the final product.
“The locomotives’ performance is going to be great here on the KiwiRail network,” he said. “Working with KiwiRail has been fantastic. The facilities are great, the help we have been receiving from KiwiRail is great, and I think we have built a very good and strong thing together.”
Gordon said KiwiRail’s locomotive engineers have given very positive feedback so far and have played a pivotal role in the development of the locomotive’s cab and overall functionality.
One such engineer, Kyle Swainson, said the switch from DXs to DMs was like going from a 1960s car to a modern 2020 vehicle.
“It’s a lot more comfortable, it’s a lot quieter,” he said. “The air con is a big thing for us – we’re not used to having air con!
“The creature comforts, from a loco engineer point of view, are amazing.
“The computer systems in the locomotives are also stand-out, compared to what we’re used to.”
What’s next
Two additional locomotives are scheduled for delivery in late October or early November 2025, while the rest will be delivered in groups of five or six, starting in January 2026, at intervals of every few months until they have all arrived.
KiwiRail Chief Executive Peter Reidy previously said in a statement that the modern machines will be a “huge benefit”, especially for the operator’s customers in the South Island, where 47 of the 66 locomotives will be based.
“As the new machines enter service, it will mean greater reliability for our freight customers, which is crucial for growing rail,” he said. “Rail is already a lower emissions transport mode, producing 70 per cent fewer emissions per tonne carried compared with heavy road freight.
“The DMs are built to the leading European emissions standards and are fuel efficient, with potential to further reduce emissions from our South Island fleet by 20-25 per cent.”
He said the more efficient locomotives will help New Zealand towards its overall climate change targets.“Not only do they h ave a cab at each end, reducing some of the need to run two locos on freight trains, but they also have modern traction control, to better utilise the more powerful high-speed engine,” he said.
“Being more powerful, the DMs will be able to pull larger trains, which will help to future -proof us for the freight growth expected over the long term.
“A modern standardised, locomotive fleet has been on KiwiRail’s wish list for a long time and these first two locomotives are a tangible sign that the significant investment in rail by successive governments over the past years is bearing fruit.”
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