Tūhono battery trains to quadruple Capital Connection services

Lire en français : Wellington : Alstom construira 18 trains à batterie Tūhono

Palmerston North's single weekday train to Wellington is due to become at least four return trips a day once Alstom's 18 Tūhono battery-electric trains enter service. Greater Wellington signed the NZ$1,066m, 35-year design, build and maintain contract on 8 September 2025, with rollout from 2029 and full service in 2030.

Today the Capital Connection leaves Palmerston North at 6.15am and returns from Wellington at 5.15pm, on weekdays only, calling at Shannon, Levin, Ōtaki, Waikanae and Paraparaumu, according to Horizons Regional Council. The new timetable will offer at least four weekday return trips and two return trips on Saturdays and Sundays. In its statement on the signing, Horizons said weekday services would be quadrupled and weekend services introduced, after more than 15 years spent fighting to keep the once-a-weekday return.

The Wairarapa line to Masterton gains too. Greater Wellington chair Daran Ponter said the Tūhono fleet "will double peak time trains, increase off-peak services and support regional growth", in the council's announcement.

Five cars, 475 passengers, battery where the wires stop

The order covers 18 five-car Adessia Stream B battery-electric multiple units carrying up to 475 passengers at up to 120 km/h, plus 35 years of maintenance, Alstom said, valuing the deal at 538 million euros. Horizons says the units will run on both electrified and non-electrified track, switching to battery where needed. Alstom will build them at its Savli plant in India and maintain them from a new depot in Masterton. Wheelchair, bicycle and luggage spaces, accessible toilets, vending machines and water dispensers are planned.

The name, meaning "to connect" or "to unite", was approved by mana whenua. Horizons chair Rachel Keedwell said it "helps to reflect the history of the service".

Track, crossings and stations come first

The trains are only part of the Lower North Island Rail Integrated Mobility (LNIRIM) programme, which Greater Wellington, Horizons and central government fund together. Horizons puts the government's commitment to the Manawatū and Wairarapa lines, including the new fleet, at NZ$802.9m.

KiwiRail is delivering the infrastructure. Its programme includes platform upgrades at Solway, Woodside and Shannon, new and longer passing loops on both lines, more than 40 km of renewed track on the Wairarapa line, including 9 km in the Remutaka Tunnel, and new signalling due to go live in early 2027, Greater Wellington said. Safety upgrades were complete at 21 of 30 level crossings at the time of the signing. Ōtaki's historic station building is being strengthened, and improvements at Levin are under investigation.

Timing is the main risk for passengers. Alstom says the current diesel locomotive-hauled trains are due for retirement in 2028 and 2029, while the full Tūhono service is not expected until 2030; none of the partners has yet published how that gap will be covered. For Horowhenua, whose population Horizons expects to pass 66,000 by 2051, the extra trains are the main gain, especially for Shannon, which has few other transport options.

The next milestone is in Masterton, where Calder Stewart Construction is due to start building the maintenance depot in 2026, Greater Wellington announced on 28 April 2026. Battery trains are spreading elsewhere too, as in Chicago, where Metra has shown its first Stadler battery train.

Sources: Greater Wellington, news release (08/09/2025); Alstom, press release (08/09/2025); Horizons Regional Council, news release (08/09/2025); Horizons Regional Council, passenger rail page (accessed 01/11/2026); Greater Wellington, Masterton depot (28/04/2026).

Photo: the Capital Connection at Paekākāriki, north of Wellington, February 2024. Takeshi Aida, CC BY-SA 2.0, via Wikimedia Commons.

Article written with the help of AI from the sources cited above, reviewed by the TrainsNews editorial team. Real photo, credited below the image. Spotted an error? contact@trainsnews.com – Our AI charter