North Island Main Trunk Railway

Infobox rail line
logo =
name = North Island Main Trunk

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image_width = 300px
caption = Map of the North Island Main Trunk Railway
type = Main line
system = New Zealand railway network
status = Open
locale = North Island, New Zealand
start = Wellington
end = Auckland
stations =
routes =
ridership =
open = 6 November 1908
close =
owner = ONTRACK
operator = KiwiRail
Tranz Scenic
Tranz Metro (Wellington to Paraparaumu)
Veolia (Auckland to Pukekohe)
character = Main line
stock = EF class electric locomotives
linelength = km to mi|num=681|spell=Commonwealth|wiki=yes
tracklength =
notrack = Double track Wellington-Pukerua Bay, Paekakariki-MacKays Crossing, Hamilton-Te Kauwhata, Amokura-Auckland, remainder single track
gauge = RailGauge|1067|al=on|lk=on
el = 1500V DC overhead (Wellington to Paraparaumu)
25kV 50Hz AC overhead (Palmerston North to Te Rapa)
speed = 120 km/h maximum
elevation = m to ft|num=815|spell=Commonwealth|wiki=yes

ImageStackRight|170

The North Island Main Trunk line (NIMT) connects Auckland and Wellington, the two major cities in New Zealand's North Island. The line is the standard New Zealand gauge of 1067 mm (3 ft 6 in). A train going north, towards Auckland, is an "up" train with an even number, and one heading southwards is a "down" train with an odd number. Distances are measured from Wellington to Auckland. The convert|681|km|mi|adj=on line was completed in 1908, and through expresses operated from 1909.

The North Island Main Trunk has been described as an "engineering miracle", with numerous engineering feats especially between along the Rangitikei River and on the North Island Volcanic Plateau. This included the building of the famous Raurimu Spiral to allow trains to manage the steep grade from the Whanganui River valley onto the Volcanic Plateau. The NIMT also contains nine major viaducts, of which five are over convert|70|m|ft|0 high - Makohine (convert|73|m|ft|0|abbr=on|disp=/), South Rangitikei (convert|78|m|ft|0|abbr=on|disp=/), Kawhatau (convert|73|m|ft|0|abbr=on|disp=/), North Rangitikei (convert|81|m|ft|0|abbr=on|disp=/), and Makatote (convert|79|m|ft|0|abbr=on|disp=/),

The line is credited for having been an economic lifeline for the young nation, and for having opened up the centre of the North Island to European settlement and investment.

History

Construction

Auckland - Te Awamutu

Auckland's first railway southwards was the km to mi|13|abbr=yes line between Point Britomart and Onehunga, opened in 1873. It included what is now the Onehunga Branch from Penrose, branching off the line intended to be built to the Waikato, possibly to support the Invasion of the Waikato. From Penrose the line was extended south to Mercer by 20 May 1875, with km to mi|29|abbr=yes from Ngaruawahia being constructed by the Volunteer Engineer Militia and opened on 13 August 1877. It was extended to Frankton by December 1877, and to Te Awamutu in 1880. An economic downturn stalled construction for the next five years, and Te Awamutu remained the operating railhead. There were also protracted negotiations with local Māori, and the King Country was not accessible to Europeans until 1883.

Double Line Automatic Signalling (between Auckland and Amokura, Te Kauwhata - Hamilton) and Centralised Traffic Control (Amokura to Te Kauwhata with a crossing loop at Whangamarino) are used.

Central North Island

From Te Awamutu it was proposed that the line be built via either Taupo (see Taupo Railway Proposals) or via Taumarunui, the eventual route. Construction of the final central section of line began on 15 April 1885, when Wahanui Maniopoto paramount chief turned the first sod outside of Te Awamutu. It was 23 years before the two lines met, as the central section was difficult to survey and construct. The crossing of the North Island Volcanic Plateau with deep ravines required the construction of nine viaducts and the world-famous Raurimu Spiral. By the end of 1907 there was a 39-km (24-mile) gap between Raurimu and Ohakune, with a connecting horse-drawn coach service. From Ohakune south to Mataroa the Public Works Department operated the train, as this section had not yet been handed over to the Railways Department.

From Palmerston North to Te Rapa Centralised Traffic Control signalling is used with crossing loops at Bunnythorpe, Feilding, Maewa, Rangitawa, Greatford, Marton, Porewa, Hunterville, Mangaonoho, Mangaweka, Utiku, Taihape, Mataroa, Ngarukehu, Hihitahi, Waiouru, Tangiwai, Ohakune, Horopito, Makatote, National Park, Raurimu, Oio, Owhango, Kakahi, Mananui, Taumaranui, Okahukura, Ongarue, Waimiha, Poorotarau, Kopaki, Puketutu, Te Kuiti, Hangatiki, Otorohanga, Te Kawa, Te Awamutu, Te Haupo, Rukuhia and Hamilton Platform.

There is a siding at Winstones between Tangiwai and Ohakune for the Pulp Trains.

Opening

The gap was closed on 7 August 1908 for the first through passenger train, the 11-car Parliamentary Special carrying the Prime Minister Sir Joseph Ward and other parliamentarians north to see the American Great White Fleet at Auckland." [http://www.nzherald.co.nz/category/story.cfm?c_id=97&objectid=10526022 Steel backbone an economic lifeline ] " - "The New Zealand Herald", Saturday 09 August 2008] But much of the new section was temporary, with some cuttings north of Taonui having vertical batters and some unballasted sections of track. Ward drove the last spike on 6 November 1908. The 'Last Spike' monument is at Manganui-o-te-Ao coord|39|16.44|S|175|23.37|E|region:NZ_type:landmark, near Pokaka. A two-day NIMT service started on 9 November, with an overnight stop at Ohakune.

On 14 February 1909 the first NIMT express left Auckland for Wellington, an overnight trip scheduled to take 19 hours 15 minutes, with a sleeping car, day cars with reclining seats, and postal/parcels vans. The dining car went on the north express from Wellington to Ohakune, then transferred to the south-bound express, so avoiding the heavy gradients of the central section.

Wellington - Longburn

The Wellington-Longburn (near Palmerston North) section was constructed between 1881 and 1886 by the Wellington and Manawatu Railway Company (WMR). The company was acquired by the New Zealand Railways Department in 1908, following the completion of the central section.

Signalling Systems used are Double Line Automatic (from Wellington - South Junction and North Junction - McKays Crossing) and Centralised Traffic Control (South Junction - North Junction, McKays - Palmerston North).

Crossing Loops at Paraparaumu (Loop not electrified), Waikanae, Te Horo, Otaki, Manukau, Ohau, Levin, Koputaroa, Shannon, Tokomaru, Linton, Longburn and Palmerston North Platform.

Track upgrades

Several sections of the line have been upgraded and deviated. In the 1930s the original WMR line was deviated between Wellington and Tawa Flat, with most of the original line retained as the Johnsonville Line. Also in the 1930s the Auckland-Westfield section of line was deviated via Hobsons Bay. In the 1950s the line north from Tawa to Porirua and Plimmerton was duplicated and the section from Porirua to Plimmerton straightened by harbour reclamation. Between 1964 and 1966 the line was deviated from the centre of Palmerston North via Milson on the edge of the city. In 1981 the Mangaweka-Utiku deviation, with three viaducts, opened. The central section of the line, from Te Rapa near Hamilton to Palmerston North, was electrified in the 1980s: tunnel clearances were increased and curves eased.

Electrification

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.

Wellington

The first part of the NIMT to be electrified was Wellington-Paekakariki via the Tawa Flat deviation, in 1940 at 1500 V DC. Electric traction in this section is now used only by Tranz Metro for its suburban passenger services, extended north to Paraparaumu in 1983, and to be extended to Waikanae by 2010.

Post-war proposals

From 1948 to 1951 the General Manager of the Railways Department, Frederick Aicken, advocated electrification of the entire line, despite protests from his engineering staff.

Following the Second World War railway services 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. He turned his attention to electrification, mainly because be saw that it could relieve the coal situation and prevent high expenditure on imported fuels.

He commissioned a study into electrification, which concluded that a low frequency alternating current system could be cheaper than the 1,500 V DC system. Aicken 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 two experts from Sweden commented on the proposal and in December 1950 the Government granted approval in principle and agreed to appoint Thelander as a consultant. However, Aicken fell out with the then National Government, and retired as General Manager in July 1951. 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 bulk electrical energy generated substantially from New Zealand resources and the cost of generating electricity in small plant using imported diesel fuel.

However, the Royal Commission on Railways created following Aicken's tenure rejected the report's findings. Aicken's successor, H.C. Lusty, terminated the tentative contract and ordered D^A class diesel-electric locomotives.

Central North Island

The km to mi|411|abbr=yes section between Palmerston North and Hamilton was electrified at 25 kV 50 Hz AC, opened in June 1988 as one of the previous 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 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, for example, that whereas a diesel locomotive could haul 720 tonne trains at convert|27|km/h|mph|0|abbr=on up the Raurimu Spiral, an electric locomotive could haul 1,100-1,200 tonne trains at convert|45|km/h|mph|0|abbr=on, 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 in the report, which showed a rate of return of 18%. Sensitivity analyses showed that this high rate of return gave the project robustness against lower traffic volumes than expected (the return remained positive even if traffic falls), against significant increases in construction cost, and against lower than expected rises in the diesel fuel price.

The future

The Greater Wellington Regional Council has approved extension of the 1500 V DC Wellington electrification north from Paraparaumu to Waikanae by 2010, with the introduction of new electric multiple units (EMUs). This will leave an km to mi|80.8|abbr=yes gap to the central NIMT electrification, which starts at Palmerston North. Since the systems are different, either multi-current locomotives and/or multiple units (such as the Japanese EH500 or the French TGV) would be required for through working should the two systems be joined (the current EF class electric locomotives are AC only), or the Paraparaumu Line would need to be re-electrified to 25 kV AC, which would be problematic with Wellington's DC fleet (except the new Matangi units, which have AC running gear and could be converted), and the need for power breaks between the two systems at Wellington Railway Station. There is currently a proposal to extend the Double Line Automatic Signalling from McKays Crossing to Paraparaumu or even south of Waikanae.

There have been numerous proposals to electrify the Auckland suburban rail network, some dating from the 1960s. ["The Railways of New Zealand" by Churchman and Hurst] Most of these proposals coincided with proposals to electrify the NIMT in its entirety. The most recent proposals (2005), which the government has decided to implement, [cite web|url=http://www.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10440850|title=$1b Auckland rail upgrade powers ahead|author=New Zealand Herald|accessdate = 2007-05-21] are to electrify the network at 25 kV AC, the same system as on the central NIMT. [PDF|1= [http://www.arta.co.nz/shadomx/apps/fms/fmsdownload.cfm?file_uuid=A99C6001-BCD4-1A24-9CDE-FCF8BDB29DC8&siteName=arc ARTA] ] This includes km to mi|49.5|abbr=yes of the NIMT (the Southern line to Papakura), leaving a gap of km to mi|87.1|abbr=yes to the central NIMT electrification at Te Rapa. Electrification may be extended south as the Auckland suburban system expands, but this will depend on further government funding. In February 2008 Auckland Regional Council Chairman Mike Lee suggested the initial electrification might be extended to Pukekohe, leaving a 60 km gap to Te Rapa, north of Hamilton [citeweb|url=http://www.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10495008|title=Electric train lines may reach Hamilton|publisher=The New Zealand Herald|accessdate=2008-07-05|date=6 June 2008] .

Centennial

On 6 August 2008 at 9 am a train including the 100-year-old carriage AA1013 is scheduled to depart Wellington in a re-enactment of the original 7 August 1908 Parliamentary Special carrying the Prime Minister Sir Joseph Ward to Auckland [citeweb|url=http://www.times-age.co.nz/localnews/storydisplay.cfm?storyid=3775401|title=Unique rail carriage on track for re-enactment|publisher=Wairarapa Times-Age|accessdate=2008-07-05|date=28 February 2008] . It will carry a Prime Minister, overnight in Taihape, before continuing on to Taumarunui and then Auckland. Ticket are by invitation only. The carriage was restored the by Mainline Steam Trust.

A series of stamps were issued to commemorate the centennial:
* 50c - Last Spike Ceremony Manganui-o-te-ao - a photo of actual event [cite web |title=Stamp Issue Celebrates Main Trunk Line Centenary|work=New Zealand Post Stamp issue|url=http://www.scoop.co.nz/stories/CU0809/S00026.htm |accessmonthday=September 24 |accessyear=2008 ]
* $1.00 - Taumarunui, 1958 - photo of steam locomotive KA 947 pulled in the old station.
* $1.50 - Makatote Viaduct, 1963.
* $2.00 - Raurimu Spiral, 1964.
* $2.50 - Overlander, Hapuawhenua Viaduct, 2003.

Motive power

Due to its high volume and high value of traffic to NZR and the steep grades in the central section, the line used the most powerful locomotives in New Zealand.

team era

When it opened in 1908, the powerful 4-8-2 X class was introduced to handle heavy traffic over the mountainous central North Island section. Four G class Garratt-type locomotives were introduced in 1928, but these locomotives were not as effective as anticipated. In 1932 the 4-8-4 K class was introduced, and later improved in 1939 with the K^A.

Diesel era

The introduction of the English Electric D^F class in 1951 began the end of the steam era, and in 1955 with the introduction of the D^A major withdrawals of steam locomotives began. 1972 saw the introduction of D^X locomotives and the Silver Fern railcars: the latter remained in service between Auckland and Wellington until 1991.

Electric era

Central North Island

With electrification, the DX class was mainly re-assigned to the South Island and replaced by EF class electric locomotives, introduced in the late 1980s. Since then services have been worked mainly by the electrics, although some services are still diesel operated, such as paper pulp freight trains from Karioi to Wellington.

Wellington

Upon the electrification from Wellington Railway Station to Paekakariki in 1938, tenNZR ED class electric locomotives were used to haul freight and passenger trains along the length of the electrified line. DM class electric multiple units were also used for suburban passenger services on the line.

In 1952, with Wellington's electrification extended to the Hutt Valley Line, seven NZR EW class were introduced to increase capacity. They were also able to generate an extra convert|450|kW|hp|abbr=on|lk=on compared to the ED class, and could run at up to convert|100|km/h|mph|-1|abbr=on.

Following the lowering of the tunnels on the electrified section in 1967, DA class diesel locomotives could run through right into Wellington. This through-running meant that electric locomotives were no longer needed for freight or long-distance passenger trains, and by 1969, all but two of the ED class had been withdrawn. The remaining ED class locomotives and EW class stayed on for suburban passenger services until the mid-1980's, when the new EM class electric multiple units were introduced in 1982. With the EM class introduction, DM class units were relegated to peak services and the Johnsonville Line.

Today, only the EM class electric multiple units use Wellington's electric lines, while all other trains are diesel-hauled. The Matangi electric multiple units will operate on the Wellington electric lines when they are introduced in 2010.

Connecting lines

The following lines connect with the NIMT:
* Auckland-Newmarket Line, also known as Newmarket Branch, at Quay Park Junction.
* North Auckland Line, at Westfield.
* Mission Bush Branch (formerly Waiuku Branch), at Paerata.
* Glen Afton Branch (closed), at Huntly.
* Glen Massey Branch (closed), at Ngaruawahia.
* East Coast Main Trunk, at Hamilton.
* Stratford - Okahukura Line, at Okahukura.
* Raetihi Branch (closed), at Ohakune.
* Marton - New Plymouth Line, at Marton.
* Taonui Branch (closed), at Taonui.
* Palmerston North - Gisborne Line, at Palmerston North.
* Foxton Branch (closed), at Longburn.
* Wairarapa Line, at Kaiwharawhara.
* Johnsonville Line, at Wellington.

Passenger services

Long-distance

From the opening of the line there have been regular passenger services between Wellington and Auckland.

Between 1963 and 1968 day-time services on the line were known as the Scenic Daylight. In 1968, an RM class 88-seater railcar was refurbished and repainted in a distinctive blue scheme that led to it being nicknamed the Blue Streak. It initially operated an unsuccessful service between Hamilton and Auckland in early 1968, and was transferred to the Auckland-Wellington run on 23 September 1968.

In 1971 NZR introduced the Silver Star, a luxury sleeper train. The service was not economically viable, and was withdrawn in 1979. Much more successful was the Silver Fern, a daytime railcar service, introduced in 1972 to replace the "Blue Streak". This service was withdrawn in 1991 and replaced by The Overlander, now operated by Tranz Scenic.On 25 July 2006 Toll announced that the Overlander would cease at the end of September 2006, but on 28 September 2006 the train's continuation on a limited timetable was announced. [cite news| url=http://www.nzherald.co.nz/section/story.cfm?c_id=1&ObjectID=10403445| title=Overlander to continue running| publisher=New Zealand Herald| date=2006-09-28| accessdate=2007-10-15| ] Organisations such as the Railway Enthusiasts Society run charters.

Tranz Scenic also operates the Capital Connection between Palmerston North and Wellington.

Auckland suburban

Within the Auckland Region between Britomart and Pukekohe suburban trains runs on the NIMT at regular intervals. Services terminate at Britomart Transport Centre, all using the NIMT from Quay Park Junction.

Eastern Line (Pukekohe, Papakura and Otahuhu to Britomart via Glen Innes) trains run along the NIMT between Pukekohe and Britomart.

Southern Line (Pukekohe, Papakura and Otahuhu to Britomart via Newmarket) trains run along the NIMT from Pukekohe to Westfield, the North Auckland Line to Newmarket, and the Auckland-Newmarket Line to the NIMT at Quay Park junction.

Wellington suburban

Wellington's suburban network, operated by Tranz Metro, includes the southern portion of the NIMT, between Wellington and Parapararumu, known as the Paraparaumu Line. Services terminate at Wellington railway station.

Record runs

Record runs on the NIMT from Auckland to Wellington were the 1960 Moohan Rocket (train) of 11 hours 34 minutes in 1960, and the Standard railcar time of 9 hours 26 minutes (running time 8 hours 42 minutes) in 1967.

References

* "North Island Main Trunk: An Illustrated History" by W.A. Pierre (1981, A.H. & A.W. Reed), ISBN 0 589 01316 5.

See also

* List of Auckland railway stations
* List of Wellington railway stations

External links

* [http://www.tranzscenic.co.nz/services/overlander.aspx The Overlander; the current passenger service] .
* [http://www.nzhistory.net.nz/node/2459 A history of the NIMT & Overlander, with video & sound clips]
* [http://www.ipenz.org.nz/heritage/itemdetail.cfm?itemid=71 NZ Engineering Heritage NIMT page]
* [http://www.ontrack.govt.nz/AboutONTRACK/SignificantProjects/NIMTcentenary/tabid/193/Default.aspx Centenary of the opening of the North Island Main Trunk Railway official website]
* [http://www.allaboard.org.nz Centenary celebrations website]