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 and passes through Paraparaumu, Palmerston North, Taihape, National Park, Taumarunui, Te Kuiti, Hamilton, and Pukekohe.
Most of the NIMT is single track with frequent passing loops, built to the New Zealand rail gauge of 1,067 mm (3 ft 6 in). The line is double track between Wellington and Waikanae (apart from an 8.7 km (5.4 mi) single track section between Pukerua Bay and Paekakariki), between Hamilton and Te Kauwhata (except for the single track Waikato River Bridge at Ngaruawahia), and between Meremere and Auckland Britomart. Around 460 kilometres (290 mi) (approximately 65%) of the line is electrified in three separate sections: one section at 1600 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 for the young nation, and for having opened up the centre of the North Island to European settlement and investment. In the early days, a passenger journey between Wellington and Auckland could take more than 20 hours; today, the Northern Explorer takes approximately 11 hours.
The NIMT has been described as an "engineering miracle", with numerous engineering feats such as viaducts, tunnels and a spiral built to overcome large elevation differences with grades suitable for steam engines.
Video North Island Main Trunk
History
Construction
Auckland to Te Awamutu
Auckland's first railway was the 13 km (8.1 mi) line between Point Britomart and Onehunga via Penrose, opened in 1873 (see photo of first train). It was built by Brogdens. The section from Penrose to Onehunga is now called the Onehunga Branch. The line was later continued south from Penrose into the Waikato, possibly to support the Invasion of the Waikato, a 3.5 mi (5.6 km) tramway being built from Maungatawhiri to Meremere in 1864, though turning of the first sod of the Auckland and Drury Railway took place in 1865, a year after the last major battle. This line reached Mercer by 20 May 1875, with 29 km (18 mi) 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 railhead. There were also protracted negotiations with local M?ori, and the King Country was not accessible to Europeans until 1883.
Wellington to Marton
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.
Central North Island
From Te Awamutu it was proposed that the line be built via Taupo or via Taumarunui, the eventual route. Four options were considered before the Minister of Public Works decided on the present route in 1884, but, when it was realised just how difficult that route was, further surveys considered two other options in 1888. Construction of the final central section began on 15 April 1885, when paramount chief Wahanui of Ng?ti Maniapoto turned the first sod outside 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 nine viaducts and the world-famous Raurimu Spiral. By the beginning of 1908, there was a 39 km (24 mi) gap between Erua and Ohakune, with a connecting horse-drawn coach service. From Ohakune south to Waiouru the Public Works Department operated the train, as this section had not yet been handed over to the Railways Department.
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. 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, and the 'Last Spike' monument is at Manganui-o-te-Ao 39°16.44?S 175°23.37?E, 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 southbound express, so avoiding the heavy gradients of the central section.
Track upgrades
Several sections of the line have been upgraded and deviated:
In 1913 the maximum speed limit on the NIMT was raised to 45 mph (73 km/h), reducing the journey time by 1 hour 25 minutes Auckland-Wellington or to 17 hours and between 30 and 45 minutes. Under T. Ronaye the general manager from 1895 to 1913 the section south to Parnell was duplicated and improvements made to the worst gradients and tight curves between Auckland and Mercer. Under his successor E. H. Hiley the second Parnell Tunnel with two tracks and an easier gradient was completed in 1915-1916. On the Kakariki bank between Halcombe and Marton a deviation reduced the 1 in 53 grade to 1 in 70.
In 1927 automatic colour light signalling was installed from Otahuhu to Mercer. In 1930 the signalling was extended 34 mi 72 ch (56.2 km) to Frankton and the 6 mi 55 ch (10.8 km) from there to Horotiu was doubled. The 3 mi 54 ch (5.9 km) north to Ng?ruaw?hia was doubled from 5 Dec 1937, followed by 9 mi 12 ch (14.7 km) Ng?ruaw?hia to Huntly on 4 Dec 1938 and Huntly to Ohinewai and Papakura to Paerata in December, 1939. By then, wartime shortages delayed further double-tracking. Pokeno to Mercer was doubled from 11 Nov 1951, Pukekohe to Pokeno 21 Nov 1954, Mercer to Amokura 1 Jul 1956 and Ohinewai to Te Kauwhata 14 Dec 1958. The 13 km (8.1 mi) between Amokura and Te Kauwhata remain single track, as does Ng?ruaw?hia bridge.
In 1930 the Westfield Deviation was opened, creating a new eastern route from Auckland to Westfield via Glen Innes and Hobsons Bay, running into the new Auckland railway station and providing better access to the Port of Auckland. The original section between Auckland and Westfield via Newmarket later ceased to be part of the NIMT: Auckland to Newmarket became the Auckland-Newmarket Line, and Newmarket to Westfield became part of the North Auckland Line (NAL) which runs between Whangarei and Westfield.
In the late 1930s, bridges replaced level crossings at Ohinewai, Taupiri and Hopuhopu.
The double track Tawa Flat deviation opened to goods trains on 22 July 1935 and to passenger trains on 19 June 1937, bypassing the original single track WMR line between Wellington and Tawa. With a pair of tunnels under the Wellington hills, the deviation alleviated issues with more and heavier freight traffic on the steep twisting original route. The Wellington to Johnsonville section of the original line was retained as the Johnsonville Line and the Johnsonville to Tawa section closed.
Planned in conjunction with the Tawa Flat deviation, electrification at 1500 V DC of the southern section of the NIMT from Wellington to Paekakariki was completed on 24 July 1940, eliminating the need to relieve the steep (1 in 57) gradients to the Pukerua Bay summit by a deviation to the east and the smoke problem in the new long Tawa No. 2 tunnel. The electrification allowed suburban electric multiple units to run on this section from September 1949.
Following the Tawa Flat deviation, work continued on duplication of the line from Wellington to Paekakariki to provide for more frequent suburban passenger trains. The sections from Plimmerton to South Junction, north of Pukerua Bay, and North Junction to Paekakariki were completed in 1940. The difficult section with tunnels between South and North Junctions remains single track. Duplication from Tawa to Porirua opened on 15 December 1957, from Porirua to Paremata on 7 November 1960, and Paremata to Plimmerton on 16 October 1961.The section between Porirua and Plimmerton was straightened in conjunction with the duplication by reclaiming land along the eastern shore of Porirua Harbour.
Between 1964 and 1966 the line was deviated away from the centre of Palmerston North via the Milson deviation on the edge of the city.
In 1967 the floors of the tunnels on the WMR section between Paekakariki and Pukerua Bay were lowered to enable the DA class locomotives to travel all the way to Wellington.
Between 1973 and 1981 the major Mangaweka deviation in the central section between Mangaweka and Utiku was built, with three viaducts, all over 70m tall, crossing the Rangitikei and Kawhatau rivers.
The central section from Te Rapa near Hamilton to Palmerston North was electrified at 25 kV AC between 1984 and 1988 as part of the Think Big government energy programme. Some tunnels were opened out or bypassed by deviations while in others clearances were increased, and curves eased. The section between Ohakune and Horopito was realigned with three viaducts replaced to handle higher loads and speeds. The most notable bridge replaced was the curved metal viaduct at Hapuawhenua by a modern concrete structure, though the original has been restored as a tourist attraction.
In 2009-10, the 1.5 km section of line between Wellington Junction and Distant Junction was rebuilt from double track to triple track, to ease peak-time congestion.
In February 2011 duplication between Paekakariki and Waikanae was completed as part of the upgrade and expansion of the Wellington suburban network; see Kapiti Line for more information.
In 2012-13 four bridges near Rangiriri between Auckland and Hamilton were replaced. The bridges were all over 100 years old with steel spans and timber piers, and were replaced by modern low-maintenance concrete ballast deck bridges. Bridges 479, 480, 481 & 482 were replaced, with lengths of 40 metres (131 ft 3 in), 40 metres (131 ft 3 in), 30 metres (98 ft 5 in) and 18 metres (59 ft 1 in) respectively.
Several other upgrades have been proposed in the Auckland area.
Electrification
There are three independent sections of the NIMT which are electrified: Auckland's urban network (25kV AC), Wellington's urban network (1600 V DC), and the central section (25kV AC) from Palmerston North - Te Rapa (north of Hamilton).
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.
The first part of the NIMT to be electrified was the Wellington-Paekakariki section via the Tawa Flat deviation that was completed on 24 July 1940. This was largely to prevent smoke nuisance in the 4.3 km No. 2 tunnel, and to provide for banking on the Paekakariki to Pukerua Bay section. Electric traction in this section is now used only by Transdev Wellington for Metlink suburban passenger services on the Kapiti Line, and was extended to Paraparaumu on 7 May 1983 and Waikanae on 20 February 2011. Funded by the Greater Wellington Regional Council, the extension to Waikanae coincided with the delivery of new FP class Matangi electric multiple units.
Following the Second World War railway services suffered due to skill and coal shortages. Skilled staff sought employment opportunities elsewhere in the economy. From 1948 to 1951 the General Manager of the Railways Department, Frederick Aickin, advocated electrification of the entire line, despite protests from his engineering staff. Aickin 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 he 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 AC system could be cheaper than 1500 V DC, the system in use in Wellington. 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 (Thelander and Edenius) commented on the proposal and in December 1950 the Government granted approval in principle and agreed to appoint Thelander as a consultant. However, Aickin 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 Aickin'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 a small plant using imported diesel fuel.
However, the Royal Commission on Railways created following Aickin's tenure rejected the report's findings. Aickin's successor, H.C. Lusty, revised the tentative contract with English Electric to specify DF diesel-electric locomotives. They were later found to be unreliable, and only ten were supplied. 42 DG locomotives were supplied instead for secondary lines. For main lines including the NIMT, DA class diesel-electric locomotives were ordered from General Motors.
The 411 km (255 mi) section between Palmerston North and Hamilton was electrified at 25 kV 50 Hz AC, opened in June 1988 as one of the 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 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 cost benefit report was written.
The electrification of the section, which 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, received approval in 1980. This led to a technical study carried out with assistance from the Japanese Railway Technical Research Institute. The report stated that track capacity would be increased by electrification because such traction is faster and able to move more freight at once. The report stated, for example, that whereas a diesel locomotive could haul 720-tonne trains at 27 km/h (17 mph) up the Raurimu Spiral, an electric locomotive could haul 1100/1200-tonne trains at 45 km/h (28 mph), 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 analysis showed that this high rate of return gave the project robustness against lower traffic volumes than expected (the return remained positive even if traffic fell), against significant increases in construction cost, and against lower than expected rises in the diesel fuel price.
Part of the project included replacing the copper wire communications system with a new fibre optic communications cable (due to interference caused by AC power with the DC copper wire system) between Wellington and Auckland. In 1994 New Zealand Rail Limited sold the cable to Clear Communications for telephone traffic, leasing part of it back for signalling.
Proposals to electrify the Auckland suburban rail network dated back to the 1960s, they mainly coincided with proposals to electrify the NIMT in its entirety. In 2005 the central government decided to implement a proposal to electrify the urban network at 25kV AC, the same system as on the central NIMT. This included 35.7 km (22.2 mi) of the NIMT itself, from Britomart to just south of Papakura. Work on electrification of the Auckland network began in 2010. The first revenue electric services using AM class EMUs commenced on 28 April 2014 between Britomart and Onehunga on the Onehunga Line. The electrification project on the Auckland network, including the Auckland-Papakura section of the NIMT, was completed in July 2015, with all suburban services being electric. A diesel shuttle service runs on the non-electrified Pukekohe-Papakura section.
The future
The completion of Auckland's electrification leaves a gap of 87.1 km (54.1 mi) to the central NIMT electrification at Te Rapa, north of Hamilton. Electrification may be extended south as the Auckland suburban system expands, but this will depend on further government funding. In February 2008 former Auckland Regional Council Chairman Mike Lee suggested the initial electrification might be extended to Pukekohe, leaving a 60 km gap to Te Rapa. In 2012, in response to public submissions, the board of Auckland Transport decided to include an investigation into electrifying to Pukekohe to its 10-year programme.
A paper written in 2008 for then railway infrastructure owner ONTRACK investigated the possibility of electrifying the remaining Papakura-Te Rapa gap between the Auckland urban system's terminus at Papakura on the NIMT and the central NIMT system, along with electrification of the East Coast Main Trunk to Tauranga. The report put the total cost of electrification at $860 million, with $433 million for the Papakura-Te Rapa section. It concluded that money would be better spent on grade and curvature easements, removing speed restrictions and increasing the length of passing loops.
In Wellington, there is an 80.8 km (50.2 mi) gap from Waikanae to the central NIMT electrification at Palmerston North. Since the extension of electrification to Waikanae in February 2012, there have been calls for the electrification to be extended by 15 km (9.3 mi) to Otaki. If this happens, there will be a 66 km (41 mi) gap. As the two electrification systems are different, multi-current locomotives or multiple units would be required for through electric working, should that gap be ever closed.
On 21 December 2016 KiwiRail announced their plan to withdraw from service, over the 2-year period, the EF class electric locomotives (the only electric rolling stock working the central electrified section) without replacing them. The reasons given for the decision included the fact that the EFs are now close to their end of life (approx 30 years old) and suffer from frequent breakdowns (on average every 30,000 kilometres (19,000 mi) which is well below the expected breakdown-free service interval of 50,000 kilometres (31,000 mi)) and that having to replace a diesel locomotive with an electric one and then again with another diesel one at both ends of the electrified section is labour- and time-consuming and adds to costs. The section will not be de-electrified, however, so that electric rolling stock may be reintroduced in the future, should it be found to be beneficial.
Centennial
On 6 August 2008 at 9am, a train (which included 100-year-old carriage AA1013, restored by the Mainline Steam Trust) departed Wellington in a re-enactment of the 7 August 1908 Parliamentary Special carrying the Prime Minister Sir Joseph Ward to Auckland, which the Prime Minister, stopping overnight at Taihape and Taumarunui before continuing to Auckland. Tickets were by invitation only.
A series of stamps were issued to commemorate the centennial, see Stamps:
- 50c - Last Spike Ceremony Manganui-o-te-ao - a photo of actual event
- $1.00 - Taumarunui, 1958 - steam locomotive KA 947 pulling into the old railway station.
- $1.50 - Makatote Viaduct, 1963.
- $2.00 - Raurimu Spiral, 1964.
- $2.50 - The Overlander, Hapuawhenua Viaduct, 2003.
Maps North Island Main Trunk
Infrastructure
The NIMT has been described as an "engineering miracle", with numerous engineering feats especially 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 has nine major viaducts, of which five are over 70 metres (230 ft) high - Makohine (73 m or 240 ft), South Rangitikei (78 m or 256 ft), Kawhatau (73 m or 240 ft), North Rangitikei (81 m or 266 ft), and Makatote (79 m or 259 ft).
The NIMT includes 352 bridges and 14 tunnels.
Rolling stock
Due to its high volume and high value of traffic to NZR and the steep grades in the central section, the NIMT has used the most powerful locomotives in New Zealand.
When the NIMT opened in 1909, 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 KA.
The introduction of the English Electric DF class in 1954 began the end of the steam era, and in 1955 with the introduction of the DA major withdrawals of steam locomotives began. 1972 saw the introduction of DX locomotives and the Silver Fern railcars: the latter remained in service between Auckland and Wellington until 1991.
With electrification and the introduction of the EF class electric locomotives in the late 1980s, the DX class was mainly reassigned to other areas of the network, including hauling coal on the Midland Line in the South Island. Since then services between Te Rapa and Palmerston North have been worked mainly by the electrics, although some services are still diesel operated, such as those originating from or terminating on other lines, or originating from within the central section, like the paper pulp freight trains from Karioi.
As of May 2016, regular rolling stock on the NIMT include:
- DC class - all sections
- DFT class - all sections
- DL class - all sections
- DX class - all sections
- EF class - Palmerston North to Te Rapa
Connecting lines
Notable connecting tramways and other lines
Passenger services
Long-distance
From opening there have been regular passenger services between Wellington and Auckland. The daily "Express" left earlier in the evening, followed by the "Limited", which had fewer stops for passengers.
Between 1963 and 1968 daytime trains were called 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.
In conjunction with the introduction of the carriage train Overlander service, the Silver Fern railcars were redeployed to start new services between Tauranga and Auckland - Kaimai Express, and Auckland and Rotorua - Geyserland Express, in 1991. In 2000 a new commuter service called the Waikato Connection was introduced between Hamilton and Auckland and ran in conjunction with the services to Tauranga and Rotorua until all three services were cancelled in 2001.
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. It ran daily during the summer months and thrice-weekly for the balance of the year.
In 2012 KiwiRail announced the Overlander would be replaced by the Northern Explorer, with new AK class carriages to provide a premium tourist train on a quicker timetable with fewer stops. It commenced on Monday 25 June 2012, and consists of one train running from Auckland to Wellington on Mondays, Thursdays and Saturdays, and Wellington to Auckland on Tuesdays, Fridays and Sundays. It has fewer stops than the Overlander, stopping only at Papakura, Hamilton, Otorohanga, National Park, Ohakune, Palmerston North and Paraparaumu.
The Capital Connection commuter train operates between Palmerston North and Wellington.
Both KiwiRail and private enthusiast operators such as the Railway Enthusiasts Society, Mainline Steam and Steam Inc operate charter trains.
Auckland suburban
Suburban trains run on the NIMT at regular intervals as follows:
Eastern Line (Manukau to Britomart via Glen Innes) trains run on the NIMT between Puhinui and Britomart.
Southern Line (Papakura to Britomart via Otahuhu and Newmarket) trains run on the NIMT from Papakura to Westfield, the North Auckland Line to Newmarket, and the Newmarket Line to the vicinity of Quay Park, where they rejoin the NIMT for the short section to Britomart. A diesel train shuttle service runs on the NIMT between Pukekohe and Papakura.
Onehunga Line and Western Line trains use the NIMT only for the short section from the vicinity of Quay Park to Britomart.
Wellington suburban
Wellington's Metlink suburban network, operated by Wellington Transdev, includes the southern portion of the NIMT between Wellington railway station and Waikanae railway station as the Kapiti Line.
Stations
Record runs
Record runs 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.
Gallery
See also
- List of Auckland railway stations
- List of Wellington railway stations
References
Citations
Bibliography
- Bill Pierre (1981). North Island Main Trunk: An Illustrated History. A.H. & A.W. Reed. ISBN 0-589-01316-5.
- Churchman, Geoffrey B.; Hurst, Tony (1991). The Railways of New Zealand: A Journey Through History (reprint ed.). HarperCollins Publishers (New Zealand). ISBN 978-0-908876-20-4.
External links
- The Overlander; the current passenger service.
- A history of the NIMT & Overlander, with video & sound clips
- NZ Engineering Heritage NIMT page
- Centenary of the opening of the North Island Main Trunk Railway official website
- Centenary celebrations website
- The Romance of the Rail by James Cowan c1928
- Maori station names on the NIMT
Source of the article : Wikipedia
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