Historical Significance or Value
As one of the last links in the politically significant North Island Main Trunk, the Spiral has historical importance. The Spiral configuration, devised in 1898, enabled the Government to proceed with the Central Route. The untouched Waimarino forests and vast tracts of land ready for Pakeha settlement land along this route were perceived to have enormous economic and political advantages. It was unclear however, whether these advantages were considered sufficient to outweigh the immense costs that would have been associated with the construction of Browne and Turner's route through the region, and in 1892 an alternative route was seriously considered. While it appears that the government may have become resigned to these costs by the late 1890s, the Central Route was not in fact confirmed until 1900, when Holmes' Spiral was presented for consideration. The completion of the line through the Central Plateau had enormous implications for the area, and resulted in the mass deforestation and settlement. The Spiral is integrally associated and partially responsible for these events. In addition, the construction of the Spiral is associated with the period of the Government's 'big push' to complete the North Island Main Trunk line. Between 1906 and 1908 the Government almost doubled the resources allocated to the construction of the line in an attempt to complete it by 1908. As part of this push 'good pick and shovel men' from England were given reduced fares to encourage them to travel to New Zealand to work on the line. According to Kate Hill, 'many of the navvies lured out from Britain had their first New Zealand experience in the Raurimu bush and worked long and tedious shifts building the acclaimed Spiral'. The Spiral is also partially responsible for the development of the settlement now known as Raurimu. The settlement developed on the site of a surveyor's camp known as Pukerimu. It was created to accommodate the transient railway workers employed on the Spiral. However, as these workers lived in calico tents, little remains of this original settlement other than its location. The current settlement developed out of the sawmilling industry that resulted after the completion of the North Island Main Trunk line.
In her paper on the Raurimu township, Kate Hill summarised the significance of the Spiral:
Constructed as a practical solution to a topographical problem, the Spiral commemorates the 'engineering feat' of Holmes, and from the outset was conferred with monumental status and potential archaeological significance. It also represents part of a massive colonial investment in a circulatory system that linked the nation more effectively to the global economy, while internally exercising control of place.
Technological - design
The Raurimu Spiral is of national technological significance. In 1884 surveyor John Rochfort advised that a route through the Central Plateau was both a possible and appropriate route for the North Island Main Trunk Line. Rochfort, a highly esteemed surveyor, failed to advise the government of a steep drop of 715 feet from the tableland of the National Park down to what is now the township of Raurimu. When government surveyors attempted to plot the route of the railway through this area in 1887 they undertook exhaustive explorations of the area in an attempt to discover any line through the Central Plateau. Only one practicable option resulted from this work. This was a single line surveyed by J. Barton Browne and C. B. Turner that involved 20 kilometres of line and the construction of nine viaducts. The cost of construction was estimated at £104,500, which was sufficient to prompt the government to seriously consider re-routing the line through Taranaki. Yet the benefits of the central route outweighed the costs and the government decided to go ahead. In 1897 engineer Robert West Holmes examined the problem. Instead of attempting to create a straight line down to Raurimu, he devised a seven mile (11 kilometre) spiral configuration that lost 715 feet (218 metres) of height without breaking the gradient of 1 in 50, and completely eliminating the nine viaducts required by the proposed 1887 Browne and Turner line.
The ingenuity of the design is perhaps best illustrated, as Lee points out, by an examination of the number of surveys carried out in an effort to resolve the problem. According to Lee, over 100 miles (161 kilometres) of routes were explored with a view to either avoiding the plateau or getting an acceptable route down from it, and some 60 miles (97 kilometres) were traversed and levelled. Lee further estimates that Holmes' own work prior to his discovery work probably added another 20 miles (32 kilometres) or so of trail lines to the total.
The structure is a highly acclaimed feat of engineering and the national and international recognition it has received is well documented. The concept of the Spiral prompted Lee, for instance, to note that it established Holmes as 'perhaps the greatest location engineer in New Zealand's history' and was undoubtedly a masterly piece of location and grading, both in its conception and detail'. The most recent official recognition of the Spiral's technological importance was the award in 1997 by the Institute of Professional Engineers New Zealand and the prestigious American Society of Civil Engineers, who designated the site an “International Historic Civil Engineering Landmark”.
Technological - construction
Recognised primarily for its inspired design, the construction of the Spiral also has technological importance. As Hill notes, 'it is important to bear in mind that the entire Spiral construction, from the initial bush clearance at Raurimu through to the final plate-laying at National Park, was accomplished under the co-operative system with pick and shovel technology in the short space of two years and seven months'. Because of the complexity of the Spiral, the camp was established in this location for longer than usual and therefore developed a more extensive set of associated commercial structures. The Spiral configuration, which included three horseshoe bends and a complete circle, involved massive earthworks and heavy cuttings, particularly around the circle. Beyond the shorter tunnel, for example, a cutting '26 chains long which, for seven or eight chains averages over 60 feet' (18 metres) in height. The method of creating these cuttings was for '[o]ne lot of men is tunnelling through the cutting and another lot working above them until they meet and the whole face is cut away'. As well as the earthworks, the construction of the Spiral involved a number of concrete structures. The Arline Creek and all its streamlets were culverted in concrete, and two tunnels were also built. The larger tunnel, which was completed in 1906, was thought to have a greater diameter than any other tunnel in the colony at the time it was completed. The material for this construction work was locally sourced; the spoil obtained from tunnelling was washed and used to create the concrete required.
(a) The extent to which the place reflects important or representative aspects of New Zealand history:
The Spiral is associated with the development of the railway in New Zealand and the construction of the North Island Main Trunk Line. The completion of the line revolutionised travel - after the joining of the two railheads, a rail journey between Wellington and Auckland took just two days. The development opened up the Central Plateau to Pakeha and, consequently, had enormous ramifications for race relations, politics, land settlement, and trade. The Spiral is also associated with the original settlement of Raurimu, which was representative of the short-term settlements created by transient workers employed by the Public Works Department during the construction of the North Island Main Trunk line.
(b) The association of the place with events, persons, or ideas of importance in New Zealand history:
The Spiral is a permanent memorial to engineer Robert West Holmes. Holmes devised the Spiral as an alternative that allowed the construction of the line to be undertaken at far less cost and effort than the line devised by Browne and Turner. The ingenuity he showed in both conceiving of, and designing the Spiral when numerous others had failed to find a practicable route through the Central Plateau, makes him one of the greatest location engineers in New Zealand's history. Holmes went on to help to lay the foundations for professional engineering in New Zealand, and was instrumental in obtaining the right of cadets to obtain two years' leave to study engineering at Canterbury College. His support helped to ensure that tertiary study progressively became established as the preferred route to professional qualification. Holmes also had a close involvement with the formation in 1914 of the New Zealand Society of Civil Engineers, and was twice elected to serve as president - the only man to have served more than one term. Holmes' contribution to engineering was recognised in his membership of the Institution of Civil Engineers, London, from 1897 and in his being given the Imperial Service Order in 1918.
(e)The community association with, or public esteem for, the place:
The Raurimu Spiral is held in high esteem as a great feat of civil engineering and consequently has received considerable publicity locally, nationally and internationally since its construction. In 1997 a ceremony was held to acknowledge the importance of the engineering and construction skills of those involved in the project, and to acknowledge the importance, at that time and ever since, of the connection of the two major cities of New Zealand. The Institute of Professional Engineers New Zealand and the prestigious American Society of Civil Engineers jointly designated the site an 'International Historic Civil Engineering Landmark' in 1997. The site is promoted as a tourist attraction. An observation area adjacent to the Spiral was made a recreation reserve in 1980 and was endowed with a lookout and noticeboard in 1986. The site has and still is promoted as a tourist attraction and numerous package tours are available to those wishing to explore the Spiral.
(g)The technical accomplishment or value, or design of the place:
The design of the Raurimu Spiral demonstrates outstanding technical accomplishment. It allowed the construction of the North Island Main Trunk Line through the Central Plateau, negotiating a steep drop of 715 feet from the tableland of the National Park down to what is now the township of Raurimu. Numerous surveys were carried out in an attempt to find any workable line over the drop. Just one was discovered. This line involved the enormous outlay of £104,500 to construct nine viaducts and 20 kilometres of line and almost resulted in the re-routing of the line through the Taranaki region. Holmes' spiral configuration artificially increased the direct line distance between the National Park and Raurimu to seven miles (11 kilometres), which allowed the drop to be traversed on a manageable gradient of 1 in 50. The construction of the line adds to its technological value. Built using pick and shovel technology, the Spiral configuration included three horseshoe bends and a complete circle, and involved massive earthworks and heavy cuttings.
(j)The importance of identifying rare types of historic places:
The Raurimu Spiral is unique on the New Zealand national rail network. It was devised to overcome the particular problems presented by the terrain between National Park and Raurimu, which featured a steep drop over a short distance. Internationally, spiral devices had been copy-book practice prior to 1898 on Swiss and Canadian railways. However, as Fletcher notes, spirals required considerable ingenuity to develop without excessive tunnelling and with seven and a half chain curves minimum radius and, accordingly each spiral has to be adapted to the particular terrain and are therefore unique configurations.
(k)The extent to which the place forms part of a wider historical and cultural complex or historical and cultural landscape:
The Raurimu Spiral is an integral part of the drama that revolved around the completion of the North Island Main Trunk Line. It is one of a number of key structures along the line, such as the Hapuawhenua and Makatote Viaducts, that were associated with the 'big push' to complete the line by 1908. In addition, the Spiral is intimately linked with the wider historical and physical landscape of the line and is part of a larger archaeological landscape that includes the settlement site, the service roads and any remnants of the construction camps used by those who worked on the line.
The North Island Main Trunk Line
In 1870, prompted by the then Colonial Treasurer Julius Vogel (1835-1899), the Government adopted bold, expansionist policies to bring thousands of assisted immigrants to New Zealand to construct roads, railway, bridges and telegraph lines. Part of his vision was to create a 'North Island Main Trunk Line' that would connect the country's two main cities, Auckland and Wellington, by rail. At a time when there had been virtually no Pakeha penetration of the North Island Central Plateau, and the King Country remained part of the colony over which the government had 'no practical control', Vogel's vision was more of dream than a practical suggestion.
By 1880, existing railway lines had been extended in both the north and the south of the Island. A railway had been opened from Palmerston North via Marton to Wanganui, and further lines opened in Taranaki, and in the Auckland district the line through Mercer had been extended into the Waikato as far to Te Awamutu on the border of the King Country. To achieve Vogel's vision, approximately 200 miles (322 kilometres) of rail would have to be constructed between Marton and Te Awamutu, to connect the lines that were already in operation. In 1882 the government enacted the North Island Main Trunk Railway Loan Act to raise the finance (£1,000,000) for closing the gap between the railheads, and began negotiations with Maniapoto chiefs for permission to survey a route for the line through the King Country.
In 1883 chiefs Rewi Manga Maniapoto (?-1894) and Wahanui Huatare (?-1897) agreed to allow surveyors to map the railway route through the King Country. While the pair remained strongly opposed to the sale of Maori land, they recognised that the King Country would eventually be opened to Pakeha, and chose to control the process by imposing conditions on the construction of the line. In September 1884, Wahanui declared that he would co-operate with the government over the railway on certain conditions, and he outlined these at the House of Representatives on 1 November 1884. The conditions included the right of the King movement to manage their own affairs, the banning of liquor from Waikato-Ngati Maniapoto territory, and the right of his people to have sole responsibility for administering their ancestral lands.
The Work of John Rochfort (1832-1893)
In June 1883, surveyor and engineer John Rochfort set out to inspect the territory through which the proposed line would be laid. During his journeys, Rochfort met with strong resistance from Maori opposed to the construction of the line, and for three days was held prisoner at Papatupu, near Ohakune. Rochfort surveyed a route through the North Island's mountainous Ruapehu region and in February 1884 confidently reported to the Engineer in Charge of the Public Works Department that 'the central route from Marton to Te Awamutu [w]as the best for the North Island Main Trunk Railway'. Following the completion of Rochfort's survey, a government commission of enquiry was held to ensure that no serious problems would surface if this route was selected. One of the questions raised at this enquiry was the gradient required to traverse the mountainous central plateau region. When asked whether the steepest gradient would be no more than 1 in 70, Rochfort responded 'Yes, I feel confident of that, and can prove it on plans I possess'. The commission took Rochfort at his word. Parliament approved the central route and, on 15 April 1885, a ceremony for the turning of the first sod on the new line was held near Puniu, 2 miles (3.2 kilometres) south of the northern railhead at Te Awamutu.
The Descent from the Central Plateau
Travelling north from the Rangitikei region, Rochfort's proposed line crossed through the Central Plateau in the Ruapehu region. At the highest point in this volcanic region, the land rose to over 2500 feet (762 metres) above sea level. It then dropped away sharply towards the Wanganui Valley. To reach the Wanganui Valley from the National Park the line would have to descend almost 1800 feet (549 metres) in approximately 16 miles (26 kilometres). This meant that the line would require what was an achievable gradient of approximately 1 in 47. Yet in the first 1.25 miles (2 kilometres), the land dropped sharply away towards Raurimu, creating an abrupt fall of 434 feet (132 metres). This created a gradient of 1 in 15. The steepness of this descent meant that Rochfort's claim that the line would require a gradient of no more than 1 in 70 was, as was reported to the House of Representatives in 1892, 'exceedingly erroneous'.
Attempts to Traverse the Central Plateau
By 1887, despite hindrances caused by the difficult terrain and reduced government funding, the North Island Main Trunk Line had been opened to Te Kuiti, located 42 kilometres south of Te Awamutu. At the southern end, 30 kilometres of track had been laid. Attention turned to the Central Plateau, where the difficulties in finding a practical route between National Park and Raurimu were becoming increasingly clear. In 1887, the Engineer in Chief reported to the Minister of Works that 'two parties have recently been started to run trial gradients from the Waimarino Plateau to the Upper Whanganui Valley. The works on this section are not expected to be very heavy, but it will possibly be necessary to adopt a somewhat steeper gradient than on the portions of line now under construction'. Following exhaustive explorations of the area, these two parties proved that it was in fact impossible to achieve Rochfort's gradient of 1 in 70. Nine surveys were carried out to try and discover any practicable line through the Central Plateau. The only practicable option was a line surveyed by J. Barton Browne and C. B. Turner, which achieved a gradient of 1 in 50 down from National Park, past Raurimu and towards the Piopiotea Valley. The 20-kilometre line required the construction of an extra nine viaducts, three of which would be a minimum of 100 feet (31 metres) high. Although this made re-routing the line through the Taranaki region appear in a more attractive light, anticipated financial and other benefits of the central route created considerable pressure to continue with the existing route, and in 1892 a Committee of Inquiry into the matter simply stated that further exploration and survey was necessary before the final route would be determined.
It was clear that the pursuit of the central route would involve the Government in an expense of a magnitude not conceived of when Rochfort's route through the Central Plateau was adopted. In 1884, for instance, it was estimated that the cost of constructing the entire line between Marton and Te Awamutu would be approximately £1,293,134. The cost of the route through the Central Plateau was estimated at no more than £19,565. In 1894 the cost of the route through the Central Plateau alone was estimated at £174,250, with the cost of Browne and Turner's 20 kilometres of line and nine viaducts coming to £104,500.
Robert West Holmes' Solution (1856-1936)
Robert West Holmes, born in London, England, had arrived in New Zealand in 1871 at the age of 15 and joined the Public Works Department as a draughtsman the following year. He later served as a resident engineer in New Plymouth, where he investigated alternative routes for the proposed rail line through Taranaki, and was given charge of the North Island Main Trunk Railway Line in 1891. In 1893 the engineer began work re-surveying part of the line through the Central Plateau. By 1897 he had completed the work up to the point where the 20 kilometres of line proposed by Browne and Turner were required if the line was to reach the Piopiotea Valley. The following year, Holmes sent a report to the Engineer-in-Chief noting that 'A better line has been obtained down the Piopiotea River Valley than was expected to be got'. In 1899 it was reported that, due to this new line, 'All the viaducts between Waimarino and the Wanganui River have been avoided'. Holmes had found an ingenious means of traversing the drop toward the Piopiotea Valley that meant that Browne and Turner's solution, the only other practicable solution, was no longer required.
Traversing the Central Plateau
As was reported in the Herald on 12 September 1898, 'the supposed impossible engineering feat of dropping down from the tableland on the central route to the valley of the Wanganui on a good grade has been completely accomplished by Mr. Holmes making use of the ...device of a loop to gain distance and so reduce the grade'. Instead of creating a straight line down the 3 and a half miles to the valley as Browne and Turner had done, Holmes had designed a spiralling line seven miles (11 kilometres) long, which lost 715 feet (218 metres) of height without breaking the gradient of 1 in 50. The solution was far shorter and much cheaper than the tortuous line laid out in 1887 by Browne and Turner.
From the clearing of the bush to the final plate-laying at National Park, work on Holme's solution, the 'Raurimu Spiral', was completed in just two years and seven months and included three horseshoe bends, two tunnels and a circle. Transient railway workers employed on a day-to-day basis by the Public Works Department constructed it. These workers began moving to the area to work on the spiral in 1905. When engineering cadet Peter Keller arrived on the site of the future Raurimu township in March 1905, he reported that the area was 'all-pervading forest'. By 1906 Raurimu was a township of calico tents. It boasted a population of over 1000 and had a number of public buildings included 'a post office, town hall, school, railway station'. Yet the weather conditions meant that the work was sporadic. As men were paid only for days worked, the actual money earned tended to be low, while the isolated nature of the settlement meant that the cost for goods was very high. It was not uncommon for the workers to fall into debt and in 1906 the Auckland Weekly News noted that debt meant that '[m]any of the men...cannot get away'. The spiral was completed in 1908 and stands as a lasting testimonial to the transient population of rail workers that founded the Raurimu township.
Completion of the Line
On 6 November 1908, 38 years after it was first proposed by Vogel, the North Island Main Trunk Line was officially completed. During the celebratory ceremony, the then Prime Minister Joseph George Ward (1856-1930) drove a silver-plated spike, the 'last spike', symbolising the completion of the project and the connection of Wellington with Auckland by rail. Regular passenger services between Auckland and Wellington commenced later that same year.
To transport passengers across the Central Plateau large, New Zealand built coal and, later, oil-fired steam locomotives of the 4-8-4 type, classes 'K' and Ka' were used on the North Island Main Trunk Line and travelled the 1 in 50 gradient of the Raurimu Spiral. From 1965, diesel-electric locomotives of the 80 tonne (1425 hp) 'Da' class, and their larger successors, were used on all types of trains over this section. These locomotives could haul 380 tonnes per engine up the spiral at the same speed as steam locomotives and at a much lower cost. From 1973, the 97-tonne 2040 kW (2750 hp) 'Dx-class diesel-electric locomotives were introduced. These could haul 700 tonnes up the Spiral.
In 1980, an area adjacent to the Spiral was made a recreation reserve and, six years later, the Minister of Railways, opened a lookout over the Spiral. An information board that outlined the history of the spiral was also erected. In 1997 a ceremony was held to acknowledge the importance of the engineering and construction skills of those involved in the project, and to acknowledge the importance, at that time and ever since, of the connection of the two major cities of New Zealand. The Institute of Professional Engineers New Zealand and the prestigious American Society of Civil Engineers jointly designated the site an 'International Historic Civil Engineering Landmark'. The Spiral continues to be used today.
The Raurimu Spiral consists of track laid in an ascending spiral that increased the distance between National Park and Raurimu from 5.5 kilometres in a direct line to 11.5 track kilometres. From the Raurimu Station site, the track begins to rise towards the south-east on a gradient of 1 in 50. It then incorporates a horseshoe bend. This bend has a radius of 198 metres, which brings the line back to the north-west where the station was located. The track then includes a second curve, which brings the track to the east up the hill and away from the station site. This curve has a radius of 200 metres. The track continues in a straight line towards the east before reaching a third curve. This third curve redirects the track to the south and also has a radius of approximately 200 metres. The line then enters a concrete tunnel, which is 384 metres long and was, when constructed, reported be have a greater diameter than any other tunnel in the colony. The mouth of this tunnel is marked with the date '1906'. Before emerging from this tunnel, the line begins to curve towards the west. The line then enters a second concrete tunnel 96 metres long. Emerging from the tunnel it continues to follow the curve started in the first tunnel and travels in a complete circle. This curve was built over a 91 metre long concrete culvert created to contain the Arline creek. At the end of the circle, which has a radius of 200 metres, the track loops back over the first tunnel and then travels south-east towards National Park.
The Raurimu Spiral, which consists of the railway track, railway corridor, the culverts, and two tunnels.
Raurimu Spiral Scenic Reserve created.
1905 - 1908
Heavy weight standard gauge rails constructed as a single track, from the 351km marker to the 359km (distances measured from Wellington), originally laid end-on-end joined by metal plates but now continuously welded section, set originally on hardwood sleepers obtained from the nearby Kakahi Sawmill, but now on concrete sleepers, resting on chip ballast.
The two tunnels (90.5metres and 382 metres), and the culverts are made from concrete. The gravel used to make the concrete was obtained by washing the spoil obtained when the tunnels were excavated.
21st September 2004
Report Written By
Geoffrey B. Churchman and Tony Hurst, 'The Railways of New Zealand, a journey through history', Auckland, 1990
Dictionary of New Zealand Biography
Dictionary of New Zealand Biography
Peter Lowe, 'Holmes, Robert West 1856-1936', updated 31 July 2003, URL: http://www.dnzb.govt.nz/
R. Fletcher, Single Track: The Construction of the North Island Main Trunk Railway, Auckland, 1978
K. Hill, Raurimu Frontier Town 1900-1925: a social archaeological perspective, (Department of Anthropology, University of Auckland, Research in anthropology and linguistics, no.3), 2000
J. R. Lee, The Raurimu Spiral and Investigations into Routes for the North Island Main Trunk Railway in the Central Plateau Region, Auckland, 1956
Lee, 1956 (2)
Lee, The Exploration and Survey of the Marton-Te Awamutu Section of the North Island Main Trunk Railway in the Central Plateau, Auckland, 1956
A fully referenced registration report is available from the NZHPT Central Region Office
Many of the files that relate to this section of the Main Trunk Railway Line were destroyed when the Hope Gibbons building succumbed to fire.
In 1986 the New Zealand Historic Places Trust, working closely with community groups, paid for the building and installation of the information board at The Raurimu Spiral Scenic Reserve Lookout (NZHPT file 12021.007). This commitment to the site is an indication of the support previous Boards of Trustees have had for the concept of recognising and acknowledging the importance of the site.
The Institute of Professional Engineers New Zealand (IPENZ) and the American Society of Civil Engineers jointly awarded the North Island Main Trunk Railway the honour of being an “International Historic Civil Engineering Landmark” in 1997.
Please note that entry on the New Zealand Heritage List/Rarangi Korero identifies only the heritage values of the property concerned, and should not be construed as advice on the state of the property, or as a comment of its soundness or safety, including in regard to earthquake risk, safety in the event of fire, or insanitary conditions.