North Island Main Trunk

North Island Main Trunk
Map of the North Island Main Trunk
Overview
Status	Open
Owner	KiwiRail
Locale	North Island, New Zealand
Termini	Wellington Auckland Britomart Transport Centre
Service
Type	Heavy rail
System	New Zealand railway network
Services	Northern Explorer, Capital Connection, Te Huia
Operator(s)	KiwiRail (freight) KiwiRail Scenic Journeys (long-distance passenger) Transdev Wellington (Wellington–Waikanae) Auckland One Rail (Pukekohe–Auckland)
Rolling stock	EF class electric locomotives (Te Rapa – Palmerston North)
History
Opened	14 August 1908 (railheads meet) 6 November 1908 (official opening) 14 February 1909 (line completed)
Technical
Line length	681 km (423 mi)
Number of tracks	Triple track Wellington–Wairarapa Line junction double track Wairarapa Line junction–Pukerua Bay, Paekākāriki–Waikanae, Hamilton–Te Kauwhata, Amokura–Auckland Westfield – Wiri remainder single track
Character	Main line
Track gauge	1,067 mm (3 ft 6 in)
Electrification	1500 V DC overhead Wellington–Waikanae 25 kV 50 Hz AC overhead Palmerston North–Te Rapa, Papakura–Britomart
Operating speed	110 km/h (68 mph) maximum
Highest elevation	832 metres (2,730 ft)
Route map Legend km 681.0 Britomart Transport Centre Newmarket Line Quay Park Junction The Strand Station formerly Auckland railway station Ports of Auckland Auckland Eastern Line North Auckland Line Westfield Junction Westfield Freight Yard Auckland Eastern & Southern Lines 662.2 Middlemore Auckland Eastern & Southern Lines Manukau Branch Auckland Southern Line 646.9 Papakura Mission Bush Branch & Glenbrook Vintage Railway 628.7 Pukekohe End of Auckland suburban services Glen Afton Branch Huntly Waikato River bridge Ngāruawāhia Glen Massey Branch Rotokauri Te Rapa 542.3 Hamilton East Coast Main Trunk Te Awamutu 494.4 Otorohanga 475.7 Te Kuiti Waiteti viaduct 36m Stratford–Okahukura Line (mothballed) 397.8 Taumarunui Whanganui River bridge Raurimu Raurimu Spiral 346.8 National Park Makatote viaduct 79m Manganui viaduct Mangaturuturu viaduct Taonui viaduct Hapuawhenua viaduct 51m Raetihi Branch 317.1 Ohakune Whangaehu River site of Tangiwai disaster Waiouru Taihape former tunnels 10e & 10f North Rangitikei Viaduct 81m former tunnels 10b/10c/10d Kawhatau Viaduct 73m Mangaweka Viaduct South Rangitikei Viaduct 78m former tunnel 10a Mangaweka deviation Makohine viaduct 73m 180.3 Marton–New Plymouth Line Marton Rangitikei River bridge 153.0 Feilding Palmerston North–Gisborne Line 136.2 Palmerston North Foxton Branch Milson deviation Manawatu River Wellington–Manawatu Line Shannon 90.3 Levin Otaki End of Wellington suburban services Waikanae 48.3 Paraparaumu Kapiti Line 17.7 Porirua Kapiti Line former NIMT via Johnsonville Tawa Flat deviation Hutt Valley Line (Wairarapa Line) Interislander Ferry Terminal Wellington Distant Junction Wellington freight terminal Johnsonville Line 0.0 Wellington This diagram: view talk edit

The North Island Main Trunk (NIMT) is the main railway line in the North Island of New Zealand, connecting the capital city Wellington with the country's largest city, Auckland. The line is 682 kilometres (424 mi) long, built to the New Zealand rail gauge of 1,067 mm (3 ft 6 in) and serves the large cities of Palmerston North and Hamilton.

Most of the NIMT is single track with frequent passing loops, but has double track -

• between Wellington and Waikanae, except for 3.3 km (2.1 mi) of single-track through tunnels between North Junction (35.3 km (21.9 mi) from Wellington) and South Junction, (32 km (20 mi) from Wellington), on the Pukerua Bay to Paekākāriki section,^[1]
• between Hamilton and Te Kauwhata (except for the single-track Waikato River Bridge at Ngāruawāhia), and
• between Meremere and Auckland Britomart.

Around 460 km (290 mi) (approximately 65%) of the line is electrified in three separate sections: one section at 1500 V DC between Wellington and Waikanae, and two sections at 25 kV AC: 412 km (256 mi) between Palmerston North and Te Rapa (Hamilton) and 34 km (21 mi) between Papakura and Auckland Britomart.

The first section of what became the NIMT opened in 1873 in Auckland. Construction at the Wellington end began in 1885. The line was completed in 1908 and was fully operational by 1909. It is credited for having been an economic lifeline, and for having opened up the centre of the North Island to European settlement and investment.^[2] In the early days, a passenger journey between Wellington and Auckland could take more than 20 hours; today, it takes approximately 11 hours.^[3]

The NIMT has been described as an "engineering miracle",^[4] with numerous engineering feats such as viaducts, tunnels and a spiral built to overcome large elevation differences with grades suitable for steam engines, the ruling gradient being 1 in 50.^[5]