North Island Main Trunk Railway
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The North Island Main Trunk Railway (NIMT) is the railway line connecting Auckland and Wellington, the two major cities of New Zealand's North Island. The line is built to the standard New Zealand gauge of 1067 mm (3 ft 6 in). By convention, a train going to Auckland is referred to as an "up" train, and a train heading away from Auckland as a "down" train. The line includes the famous Raurimu Spiral.
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[edit] History
[edit] Construction
Construction of the line begun on 15 April 1885, when Wahanui Maniopoto paramount chief turned the first sod near Te Awamutu. The line was completed 23 years later, on 6 November 1908; the last spike was ceremonially driven by the Prime Minister, Sir Joseph Ward. The 'Last Spike' monument is at , near Pokaka.
The Wellington - Longburn (near Palmerston North) section of the NIMT was built by a private company, the Wellington and Manawatu Railway Company and acquired by the New Zealand Railways Department in 1908
[edit] Electrification
[edit] Early proposals
Electrification of the NIMT was mooted by Electrical Engineer Evan Parry in the first volume of the New Zealand Journal of Science and Technology in November 1918. In light of a national coal shortage following World War I, Parry argued that the network was under great strain due to ever-increasing volumes of freight, and the use of steam traction was partly to blame. Parry also noted that there was great potential for cheap hydro-electricity generation in the central North Island to power electrification.
[edit] Post-war proposals
From 1948 to 1951 the then General Manager of the New Zealand Railways Department, Frederick Aicken, advocated electrification of the entire line despite protests from his engineering staff.
Following the Second World War, railway services once again suffered due to skill and coal shortages. Skilled staff sought employment opportunities elsewhere in the economy. Aicken had previously been Staff Superintendent and Chief Legal Advisor to the Department, and considered using diesel locomotives for trains on the NIMT to be too expensive. Aicken turned his attention to electrification, mainly because be saw that it could relieve the coal situation and prevent high expenditure on imported fuels.
Aicken commissioned a study into electrification, which concluded that an alternating current system could be cheaper than the 1,500 V DC system. Aicken then sent a technical mission of four senior officers overseas in March 1949, and travelled overseas himself to negotiate a tentative contract with a British construction company. The Chief Mechanical Engineer and Chief Accountant specified and costed the system and Aicken was able to complete a substantial report justifying the NIMT electrification and submit it to the Government.
Officers from New Zealand Treasury and the Ministry of Works, and also two experts from Sweden produced comment on the proposal and eventually, in December 1950, the Government granted approval in principle and agreement to appoint Thelander as a consultant. However, Aicken fell out with the then National Government, and retired from his position as General Manager in July 1951 and with the change in regime the electrification proposal disappeared.
A key assumption of Aicken's report was that traffic on the NIMT would grow by 50% from 1948 to 1961. Since a diesel-electric locomotive was in fact a travelling power station, the savings through electrification compared to diesel could be regarded as the difference between the cost of buying in bulk electrical energy generated substantially from New Zealand resources and the cost of generating electricity in small plants using imported diesel fuel.
However, the Royal Commission on Railways, created following Aicken's tenure, rejected the reports findings. Aicken's successor, H.C. Lusty, went ended the tentitive contract and ordered DA class diesel-electric locomotives instead.
[edit] Wellington section
The first part if the NIMT to be electrified was the Wellington - Paraparaumu section, electrified at 1,500 V DC, in 1940. Electric traction in this section is used only by Tranz Metro for its suburban passenger services and was opened as far north as Paekakariki in 1940 and extended to Paraparaumu in 1983.
[edit] Central North Island section
The 411km section between Palmerston North and Hamilton was electrified at 25 kV 50 Hz AC and fully opened in June 1988 as one of the former Muldoon National government's "Think Big" energy development projects. An overall cost in excess of $100 million had been projected, with some 40% being for the locomotives, but the final cost was about $250 million. The overall economics of the project were greatly undermined by the fall of the price of oil in the 1980s, and the deregulation of land transport which removed the long-distance monopoly NZR held when the report was written.
The electrification of the section received approval in 1980 and had its genesis in a study group set up in June 1974 to report on measures to be taken to cope with increasing rail traffic volumes. This led to a technical study carried out with assistance from the Japan Railway Technical Service. The report stated that increases track capacity would be created by electrification because such traction is faster and more powerful. The report stated, by way of example, that whereas a diesel locomotive can haul 720 tonne trains at 27km/hr up the Raurimu Spiral, an electric locomotive could haul 1,100 - 1,200 tonne trains at 45km/hr, cutting 3-5 hours off journey times. Less fuel would be needed and employing regenerative braking in electric locomotives lowers the fuel consumption further.
Electrification's advantages were reflected in the economic evaluation of the report, which showed a rate of return of 18% in the study of the central section. Sensitivity analyses showed that this high rate of return gave the project robustness against changes in traffic volume less than expected, (the return remains positive even if traffic falls), against significant increases in construction cost, and against lower than expected rises in the diesel fuel price.
[edit] Potential future electrification
There are currently proposals to extend the electrification of the Wellington section north from Paraparaumu to Lindale or Waikanae, further north. Such an extension would use the 1,500 V DC system.
There have been numerous proposals to electrify the Auckland suburban rail network, some dating from the 1960s[1]. Most of these proposals coincided with the electrification of the NIMT in its entirety from Auckland to Wellington.
On 12 September 2006 the Auckland Regional Transport Authority released a study pointing to a "desperate" need for electric trains to sustain the current boom in rail patronage on Auckland's network, which had reached 566,000 passenger trips per month in August of that year. An earlier report from ARTA suggested the use of a 25kV AC system, the same as the central NIMT electrification. There have been some proposals to electrify the Hamilton - Auckland section, due to its high volume of freight, however such proposals depended on greater volumes of direct Auckland - Wellington freight.
Government ministers gave qualified support for electrification of the Auckland system, as such a system proposed by the report was estimated to cost NZ$3.6 billion dollars over twenty-five years, and would increase annual patronage to 30 million trips per year. The Mayor of Auckland, Dick Hubbard, also supported the electrifcation proposals[2]
[edit] Track upgrades
Since opening in 1908, the line has been upgraded and deviated a number of times. In the 1930s, for example, the old Wellington and Manawatu Railway Company line was deviated out of Wellington via Tawa Flat. Part of the original line is now used by Tranz Metro services as the Johnsonville Branch. During the electrification of the central section of the line in the 1980s, a curve easement programme was undertaken, and a major deviation between Utiku and Mangaweka was constructed.
- See also: Tawa Flat deviation
[edit] Motive power
The line has always received the most powerful NZR locomotives. When it opened in 1908, the powerful X class steam locomotives were introduced to handle heavy traffic over the mountainous central North Island section. 1972 saw the introduction of the DX class locomotives. With electrification the DX class was mainly re-assigned to the South Island and replaced by the EF class electric locomotives, introduced in the late 1980s.
[edit] Passenger services
From the opening of the line, there have been regular passenger services between Wellington and Auckland.
In 1971, New Zealand Railways introduced the Silver Star service, a luxury night sleeper train. The service was not ultimately economically viable, and was withdrawn in 1979. Much more successful was the Silver Fern, a daytime railcar service, which was withdrawn in 1991 and replaced by The Overlander, operated by Tranz Scenic. On 25 July 2006 it was announced that the Overlander would cease operation at the end of September 2006, but on 28 September 2006, the train's continuation on a limited timetable was announced [1]. Various organisations, such as the Railway Enthusiasts Society, also run a few charters for their members.
 The Overlander passenger train stops: (North Island Main Trunk Railway) |
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| Auckland (Britomart) | Middlemore | Papakura | Pukekohe | Hamilton | Otorohanga | Te Kuiti | Taumarunui | National Park | Ohakune | Marton | Feilding | Palmerston North | Levin | Paraparaumu | Porirua | Wellington (Railway Station) | |
[edit] Surburban Services
[edit] Auckland
Within the Auckland Region (between Britomart and Pukekohe) suburban trains runs on the NIMT regular intervals.
All Eastern Line (Pukekohe, Papakura and Otahuhu to Britomart via Glen Innes) train services run along the NIMT between Pukekohe and Britomart.
| Railway Stations on the Eastern Line (Full List) | |
| Britomart • Orakei • Meadowbank • Glen Innes • Panmure • Westfield • Otahuhu • Mangere • Middlemore • Papatoetoe • Puhinui • Homai • Manurewa • Te Mahia • Takanini • Papakura • Pukekohe | |
Southern Line (Pukekohe, Papakura and Otahuhu to Britomart via Newmarket) train services run along the NIMT from Pukekohe to Westfield where it diverges on to the North Auckland Line (NAL). It continues via the NAL to Newmarket where it branches off again on the Auckland-Newmarket Line. The Southern Line rejoins the NIMT at Quay Park junction near Britomart.
| Railway Stations on the Southern Line (Full List) | |
| Britomart • Newmarket • Remuera • Greenlane • Ellerslie • Penrose • Westfield • Otahuhu • Mangere • Middlemore • Papatoetoe • Puhinui • Homai • Manurewa • Te Mahia • Takanini • Papakura • Pukekohe | |
[edit] Wellington
Wellington's suburban network, operated by Tranz Metro, includes the southern portion of the NIMT, between Wellington and Parapararumu, known as the Paraparaumu line. The 1940 electrification terminated at Paekakariki, and it was extended north to Paraparaumu in 1983. Currently, there is a proposal to extend the electrification eight kilometres north to Waikanae. The Capital Connection currently provides passenger services between Palmerston North and Wellington.
[edit] See also
[edit] External links
- The Overlander - the current passenger service.
- Raurimu Spiral
- NZ Engineering Heritage North Island Main Trunk line page
- A history of the North Island main trunk line
| New Zealand Railway Lines | ||||||
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| Secondary lines |
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| class="navbox collapsible autocollapse" |
| North Island: |
| Marton - New Plymouth Line - North Auckland Line - Palmerston North - Gisborne Line - Stratford - Okahukura Line - Wairarapa Line |
| South Island: |
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| Midland Line - Nelson Section - Otago Central Railway - Stillwater - Westport Line - Waimea Plains Railway |
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| Branch lines |
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| class="navbox collapsible autocollapse" |
| Upper North Island |
| Cambridge - Dargaville - Donnelly's Crossing - Glen Afton - Kinleith - Kumeu-Riverhead - Mount Maunganui - Murupara - Newmarket - Okaihau - Onehunga - Onerahi - Opua - Rotorua - Taneatua - Thames - Waiuku and Mission Bush |
| Lower North Island |
|---|
| Ahuriri - Castlecliff and Wanganui - Foxton - Greytown - Johnsonville - Melling - Mount Egmont - Moutohora - Ngatapa - Opunake - Raetihi - Taonui - Te Aro - Waitara |
| Upper South Island |
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| Blackball and Roa - Cape Foulwind - Conns Creek - Eyreton - Fairlie - Little River - Lyttelton - Methven - Mount Somers - Oxford - Rapahoe - Rewanui - Hokitika/Ross - Seddonville - Southbridge - Waiau - Waimate - Whitecliffs |
| Lower South Island |
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| Bluff - Catlins River - Dunback and Makareao - Fernhill - Hedgehope - Kingston - Kurow - Moeraki - Mossburn - Ngapara and Tokarahi - Outram - Port Chalmers - Roxburgh - Shag Point - Tapanui - Tokanui - Tuatapere - Waikaia - Waikaka - Wairio - Walton Park - Wyndham |
|}
| Private lines |
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| Glen Massey Branch - Dunedin Peninsula and Ocean Beach Railway - Dun Mountain Railway - Hutt Park Railway - Kaitangata Line - Sanson Tramway - Wellington and Manawatu Railway |
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