This NIMT Historic Area features a section of the NIMT in the central North Island which was the pivotal area for the timely completion of that immense construction project, and covers approximately 200km of the rail corridor and ex-NIMT corridor. Within the area are several nationally recognised engineering feats and many representative examples, and as the sum of its parts this section of the NIMT is considered one of New Zealand's great engineering achievements. The NIMT's long beginning: The completion of the NIMT in late 1908 is described as '...one of the pivotal moments in New Zealand history' and '...arguably the New Zealand state's greatest achievement, at least in the first century after 1840, and certainly its greatest financial commitment.' The impetus for the NIMT was the need to create a direct link between New Zealand's two major cities, Auckland and Wellington. For 20 years prior to the NIMT's completion, goods and passenger traffic between these cities was typically directed from Auckland to New Plymouth via coastal shipping, then continued by ship or train onto Wellington and vice versa. The concept of the NIMT was mooted by Julius Vogel (1835-1899), then the Colonial Treasurer in William Fox's government, as part of his bold expansionist policy which was adopted by the House in 1870. With this plan Vogel intended that the railway would facilitate European access to the sealed-off King Country, or Rohe Potae, and enable the establishment of settlements which could support the railway and exploit the vast, and relatively untouched, resources of the Central Plateau region. From the mid-1860s Maori in the central North Island had repelled European encroachment by establishing, and staunchly upholding, the restricted area known as the Rohe Potae. After a decade of persistent approaches from the government regarding the area, talks between officials and some King Country chiefs regarding the establishment of the railway through their land began in earnest in 1883. A series of rigorous negotiations was then initiated with two Ngati Maniapoto leaders, Wahanui Huatare and Rewi Maniapoto. There seems to have been a feeling that the railway and European incursion into the King Country was inevitable, but these chiefs wanted to make sure that it was on their terms. In late 1884 Wahanui announced his intention to cooperate with the government over the railway, and he laid out a set of conditions before the House of Representatives on 1 November 1884. His requirements included the right of the King movement to manage their own affairs, the banning of liquor from Waikato-Ngati Maniapoto territory, the right of his people to have sole responsibility for administering their ancestral lands, and that they were compensated for the land which was used. Following this, in early 1885 surveyors were allowed into the Rohe Potae to locate possible railway routes. Because of the tenuous relationship between the Crown and King Country iwi it was felt that the negotiation process was essential. However, by only consulting with Wahanui and Maniapoto the government purposely side-stepped King Tawhiao and other leaders who opposed the railway. Therefore, this initial agreement was not universal and accordingly there were instances of resistance, such as the destruction of surveying marks. Despite some opposition, surveying and construction plans continued, and on 15 April 1885 it was Wahanui who wielded the shovel that turned the NIMT's first sod, which was then ceremonially wheeled away by Premier Robert Stout. Prior to the chiefs allowing surveyors into the Rohe Potae, possible railway corridors through the King Country were only speculative because there had not been any previous opportunity to map it in detail. There were several prospective routes for the NIMT and John Rochfort (1832-1893) surveyed for a proposed corridor through the Central Plateau between 1883 and 1887. This was said to be his tour de force because he had to start from scratch and cover a large and topographically complex area. Consequently, Rochfort spent a significant amount of time in [the] area and his tracks and huts were still used and featured on Public Works Department (PWD) plans decades later when his vision for the route was finally coming to fruition. However, it was only after much debate and delay that Rochfort's route for the NIMT was eventually followed. The Maori land which was required for Rochfort's route progressively passed into Crown ownership under the Public Works Acts of 1882 and 1894. This legislation stipulated that construction could not begin until the governor issued a proclamation detailing the middle-line that each successive section would take. However, right up until 1900 there was considerable political lobbying to have the route go through Taranaki, and this, as well as factors such as the economic depression of the 1890s, meant progress was greatly inhibited. A key reason for the NIMT project not stalling further was that there was loud public dissatisfaction over the prolonged construction period. This motivated parliament to inject significantly more resources to the project to facilitate a final flurry of activity which would see the last section between the Makohine Viaduct and Taumarunui completed. The drive to finish the NIMT: The construction of a railway was generally heralded in with the turning of the 'first sod' and book-ended with a ceremony involving the ‘driving of the last spike.' When the NIMT's first sod was turned at Puniu River, near Te Awamutu in 1885, it is probable that few would have imagined that the length of the time between ceremonies would have been as long as 23 years, despite the recognised monumentality of the task. By 1887 the first major construction contract was let, which was for the creation of the Poro-o-tarao Tunnel, and at the southern end the railhead was near Hunterville. Despite being completed in 1890, it was a further six years before railway traffic could use the line up to the tunnel. Slips were particularly troublesome at this northern end, and when combined with the infrequent delivery of construction materials, construction was held up for long periods. However, by 1901 bush clearing, the building of service roads, and formation work was underway in and around Taumarunui. At the same time at the southern end slow progress in building the Makohine Viaduct due to a series of unfortunate events including a flood and a workers strike in England, meant that the Makohine section which was begun in 1891 took a total of eleven years to finish. Throughout the entire length of the NIMT there were noteworthy structures and sites which drew on the ingenuity of the PWD engineers, contemporary engineering developments, and up-to-date techniques and materials. With the exception of features such as the Waiteti Viaduct and [Poro-o-tarao] Tunnel, the majority of the significant places are situated between the Makohine Viaduct and Taumarunui, as well as a wealth of representative types of NIMT construction era structures and sites. The completion of the Makohine Viaduct in 1902, after five years of construction, was a major hurdle and enabled the drive to complete the NIMT to progress from the south. From the north the railhead was approaching Taumarunui, and its arrival there in 1903 can be seen as a significant milestone and the deep breath before the plunge to tackle the ascent to the Central Plateau and the eventual connection of the railway. This last section of the NIMT demonstrates the variety of techniques available to the NIMT construction era engineers and is a marvel because this concentrated series of viaducts, bridges, tunnels, cuttings, embankments, culverts, stream diversions and other means of constructing the railway was managed in such a way that it only took six years to complete, whereas the construction of the central section took four times as long, and the entire NIMT took 35 years to build. A significant part of this rapid completion was the increase in resources after 1900 which enabled an injection of labourers dedicated to the project. For example, it is estimated that there were 400 to 500 people residing at and around the Makatote Viaduct work site, most of who worked on the viaduct and were immigrants from Britain or Australia in accordance with Vogel's plan. The size of this community was relatively large for the region at this time, even compared with established permanent settlements such as Ohakune which had a population of approximately 600 people in 1908. In general the advent of the NIMT boosted the European presence in the central North Island, but also affected the demographic spread of the region's pre-construction population. In particular, it has been noted that after 1900 the various Maori settlements around the Manganui-o-te-ao River were depopulated. This is because many gained employment as labourers on the NIMT and then gravitated towards the newly established European towns once their work was completed. The majority of the NIMT was built using the ‘co-operative system' which meant that the railway was divided into manageable chunks for groups of six to twelve men to complete. This system was a product of contemporary Liberal philosophy and also a result of the government being unhappy with the shoddy results from some public works which had been contracted out. The price paid for each section was determined by the supervising PWD engineer based on standard rates, and then a small percentage was added to this which was calculated in accordance with the profit margin a private contractor would have generally received. Therefore, labourers expected to earn more working as part of the ‘co-operative system' than for a private contractor. The men were paid their wages monthly based on the amount of their allocated section that they completed. However, the extent of this government control also drew criticism mainly because they determined the acceptable rate for the contract and many workers complained that this actually resulted in lower wages than they could earn working for a private firm like J & A Anderson Ltd, which was responsible for the construction of the significant ‘final push' structure, the Makatote Viaduct, and the steel superstructures of the Manganui-o-te-ao and Mangaturuturu Viaducts. A positive aspect of the system was that the PWD supplied the construction materials for the groups and also an overseer, which assured the government that materials and workmanship throughout the NIMT were of a consistent standard. However, whether they were privately contracted or part of the ‘cooperative system,' the men who worked on the central part of the NIMT did so in primitive living conditions and, in particular for those working on the ‘final push' between Ohakune and Raurimu, a harsh climate. On top of this, the nature of the work was physically strenuous and hazardous. The innumerable cuttings along the route were created primarily with picks and shovels and the tunnels carved out using picks and explosives, with lighting provided by candles and ‘well lights', which were kerosene based lamps. The inherent danger of this work is emphasised by the fact that one worker at the Mataroa Tunnel, Joseph Skerrett, is reported to have had one of his hands blown off because the dynamite caps he was holding exploded. It is therefore unsurprising that lives were also lost as a result of the construction project and working conditions. An example of this was the deaths of seven men during the construction of the Makatote Viaduct when they slipped and fell from its great height due to icy steelwork. The effects of the work could also be dangerous for those in the immediate area as was the case when a landslide was created by the tunnelling and construction work at the Makohine Viaduct and consequently killed several children and their mother. The construction project therefore not only had an immense monetary cost, but also took a physical toll. Aside from the mass of largely anonymous workers, there are certain people whose reputation as significant contributors to New Zealand engineering was cemented through their work on the NIMT. One such person was Peter Seton Hay. After becoming the first person to graduate from the University of Otago with a Bachelor of Arts in 1877, Hay joined the PWD and progressed through its ranks to become the engineer-in-chief by the time he died prematurely in 1907. Hay's designs for the Makohine, Mangaweka, Hapuawhenua, Taonui, Manganui-o-te-ao, Mangaturuturu, and Makatote Viaducts were all based on classic North American trestle viaducts. Aside from the Manganui-o-te-ao which was replaced in 1966, and the Mangaweka Viaduct which was demolished in 1982, these structures are surviving tributes to his vision and engineering prowess. Alongside his pioneering research into New Zealand's hydroelectric capabilities, these structures are considered to be his most important legacies. Another prominent engineer associated with the NIMT's ‘final push' was Frederick William Furkert (1876-1949). In 1906 the southern railhead had reached Ohakune and it became the base of operations for the works from that end with Furkert, in his role as Resident Engineer, also based there. Furkert was under considerable pressure to ensure that work progressed in keeping with the government's expectations, and the fact that the NIMT was finished on schedule in late 1908 has largely been attributed to his efficiency and management skills. The NIMT was not officially finished until the driving of the ‘Last Spike' at Manganui-o-te-ao by Premier Sir Joseph Ward on 6 November, 1908. However, prior to this event a temporary track was laid over the remaining incomplete section to enable the passage of the first through train from Wellington to Auckland between 6 and 8 August 1908; the so-called Ministerial, Parliamentary, or White Fleet ‘Special.' The rush to make the line passable for the ‘Special' meant that the ride through the unballasted section between Ohakune and Erua was a bumpy one for the dignitaries. These events, which were then followed by the first express train services in February 1909, heralded a new era in travel and the economy of New Zealand. Ups and downs: the NIMT post-construction: For the majority of the NIMT's first 50 years the railway was the main source of freight and passenger transportation in New Zealand. In this period when travel by car, if you had one, was tedious because of the state of the roads, and commercial air travel was in its infancy, the NIMT was not only used for long distance travel, but also became a way of life for the communities along its route. People used the trains to get to and from work, school, and social occasions. By the 1940s a popular service was the ‘picture trains' which transported patrons from the small towns into Taihape, Ohakune, and Taumarunui on weekend evenings to go late night shopping, or to the cinema, and dances. The travel experience through the central NIMT area was enhanced by the surrounding landscape and conservation areas such as the Tongariro National Park and the scenic reserves, and this became a central marketing tool for New Zealand Railways (NZR). The reserves were established at intervals along the length of the railway early in its history to preserve the scenery ‘for the benefit of future generations' in the midst of the milling and farming which beginning to take hold. The scenic reputation of the journey preceded it however a certain amount of imagination was required in this respect for those staring at out into the blackness on the popular night expresses. The 1920s to 1940s were the heyday of rail travel in New Zealand and this was reflected in the central part of the NIMT with the upgrading and expansion of passenger facilities at some if its stations. The presence of ‘refreshment rooms' at the three main stations in this section, Taihape, Ohakune and Taumarunui is particularly indicative of this. All of these refreshment rooms were open day and night in order to cater for passengers on the various services. At times when trains were stopped at these stations the platform would be awash with people welcoming disembarking passengers, or just there to ‘people watch.' However, the ‘refresh' was often the focus of the continuing passengers' attention at these times as they hurried to grab a snack before the train left for its next stage. This NZR service was well patronised during this period and the refreshment rooms were consistently busy. For example, between 1944 and 1948 it is estimated that each of the four trains which stopped at the Ohakune Railway Station every night contained 300 to 400 passengers, many of whom were hungry for the sandwiches and other goods made by the ‘refresh girls.' Railway stations were the ‘central community hub' of the towns along the NIMT. Not only a source of employment, the NIMT and its stations also provided an outlet for other industries in the district, and therefore milling towns, such as Rangataua and Kakahi, were heavily dependant on the railway and the associated stations and yards for their economic survival. Conversely, the contact created by the NIMT and its stations could be problematic, such as during the influenza pandemic which occurred late in 1918. Taumarunui was one of the worst affected by the virus. However, the death rates in the districts along the central section of the NIMT were also relatively high. In this way the presence of the railway was a mixed blessing. However, in general the railway was viewed as essential to the area. Stations in particular were important, not only as arrival and departure points, but because they often contained a Post Office, and sometimes the building housed a telephone exchange, as well the necessary rail operational communications equipment. Therefore, stations were often the communications centre of the towns, providing important links to the outside world for these relatively isolated communities, and as such were life-lines during emergencies. Larger scale examples of this was the role played by the Ohakune Railway Station and its staff during the Raetihi Fire of 1918, and later the station at Waiouru in the wake of the Tangiwai Disaster in 1953. It was estimated in the mid1960s that the opening of one road bridge per day was needed to keep up with demand because, just as the late 19th and early 20th century was the zenith of railway building in New Zealand, the mid 20th century saw a focus on expanding and enhancing road infrastructure assets. In the face of the greater competition from road transport and the resulting decline in passenger and then freight returns, by the mid to late 20th century NZR looked to streamline their operations, facilities, and resources on the NIMT and other railways within New Zealand. As a result, between the 1960s and 1980s non-essential services at stations were closed, such as the Refreshment Rooms in Ohakune Railway Station (1964), and Taumarunui (1975), and at Taihape in the late 1980s, and then the closure of many stations followed including Tangiwai, Hihitahi, Mataroa, Utiku, and Mangaweka in 1980, and Karioi and Manunui in 1982. Other NIMT construction era station buildings such as Waiouru, which was the highest railway station in New Zealand and had been particularly important for the transportation of military personnel, and Taihape were also removed or demolished. Likewise, low use or uneconomic lines throughout New Zealand were also closed during this period, including the Raetihi Branch Line in 1968. The outcome is that currently only the Ohakune, National Park, and Taumarunui Railway Stations remain which offer passenger facilities to NIMT travellers, and the majority of NIMT construction era station and flag station buildings have been removed. At the same time there was a national programme of modernisation and we see the introduction of systems such as Centralised Traffic Control (CTC) and the associated obsolesce of the old signalling system and its associated Signal Boxes. This was followed by other initiatives like the mechanisation of track gang work which greatly reduced staff numbers and centralised the employees to bigger stations such as Taumarunui. Technical advances and economics also influenced the replacement of many ailing railway structures with reinforced concrete, cost effective, equivalents, and within the NIMT this included the Piopiotea Stream Bridge and the Manganui-o-te-ao Viaduct. Perhaps the most noticeable change from the general public's view was the phasing out of steam locomotives from the 1950s, which was complete on the NIMT by the late 1960s. The not so obvious change which the replacement diesel locomotives allowed was that track could be systematically substituted with that of a marginally [narrower] gauge. The transformation of the NIMT into a modern railway was not lost on the public, and the upheavals drove a surge of railway nostalgia which can be seen by the ‘almost embarrassing number of steam-powered excursions' which coincided with the changes of the 1960s. While there had been changes in operations, and minor alterations as well as comprehensive up-grade programmes on the NIMT during its first 70 or so years, none were as fundamentally altering as the electrification of the line. [General upgrades to allow for heavier and faster trains had seen the policy of replacing ailing structures and eliminating or easing curves and steep grades implented since the 1960s, however the preparations for electrification saw these improvements gain impetus and urgency, because these features were undesirable in an electrified railway and impeded the smooth operation of its heavier and faster locomotives.] A result of this drive was the undertaking of perhaps the most significant railway construction project in New Zealand in the late 20th century; the creation of the Mangaweka to Utiku Deviation which was completed in 1981. Like the later Ohakune to Horopito Deviation, the Mangaweka to Utiku Deviation is one of the few sections of the NIMT that has diverted away from the NIMT construction era railway route to any great extent. This fact is a testament to the work and achievement of the early NIMT surveyors and engineers. Plans for the deviation were announced in the early 1960s. The NIMT construction era route around Mangaweka was famous for its sinuosity, its concentration of tunnels, and unsecure ground that was subject to the danger of washouts and slips. Rochfort had explored the possibility of taking the route down the eastern, rather than the eventual western, side of the Rangitikei River and then across that river and also the Kawhatau. However, it is probable that he was deterred by the number of costly and time consuming viaducts it required. Developments in engineering practices and materials by the late 20th century meant that this task, while still a considerable undertaking, was not unfeasible especially when weighed against the traffic speed advantages and reduced maintenance costs that a deviation promised. The early 1980s also saw NZR become a corporation and the commissioning of an influential report prepared in 1983 by consultants Booz, Allen, and Hamilton. This report suggested methods of making the railway profitable and the deviations in the central portion of the NIMT and electrification have aided in maintaining the feasibility of the railway as well as providing travellers with yet more engineering feats to marvel at.

CONSTRUCTION MATERIALS: Brick, concrete, corrugated iron, earth, glass, gravel, iron, steel, and timber CONSTRUCTION COMPANIES: Codelfa Construction Ltd Codelfa Construction Ltd was the Italian construction company who built the South Rangitikei Viaduct on the Mangaweka to Utiku Deviation. Ginn Brothers Ltd., Taumarunui Ginn Brothers Ltd. won the contract to construct the Taumarunui Railway Station in 1975. They completed the building in 1977. Scott Bros. Ltd, Christchurch This firm was owned by brothers John Lee (1844-1913) and George (1851-1930) Scott who both immigrated to New Zealand in 1870 from Derby, England, their hometown where they underwent their engineering training. They set up a large foundry and workshop in Christchurch in 1876 and the business manufactured farming machinery, locomotives, and other items such as the street lamps in central Christchurch. Aside from their work manufacturing steelwork for, or constructing, several prominent railway and combined bridges, the company's staple business was manufacturing Atlas ranges. Both brothers were prominent Christchurch citizens with John Lee sitting on the board of, and occasionally lecturing at, Canterbury College, and George being a member of the Christchurch City Council. Wilkins and Davies Construction Co. Ltd. Wilkins and Davies were the construction company responsible for building the Kawhatau and North Rangitikei Viaducts on the Mangaweka to Utiku Deviation. ENGINEERS: Beca Carter Hollings & Ferner Consulting Engineers Beca is an international employee-owned engineering and related consultancy services group, whose range of services includes engineering, planning, project management, architecture, GIS and surveying, cost estimating, asset management and valuations. Beca evolved from a company established in 1918. In the middle of the 20th century the company was then progressed by George Beca and Sir Ron Carter. Some of Beca's notable projects include the structural engineering for the design of the Auckland War Memorial Museum, the construction of gun emplacements during World War II, the grandstand at Ellerslie Racecourse, the Macau Tower, and many others. The company has national and international offices. Samuel John Harding (1861-1948) A New Zealand born and trained engineer, Harding was the Assistant Engineer in Hunterville from 1896, which coincided with the period when the Makohine Viaduct's construction was initiated. From 1903 he was stationed at Taihape and it is said that the 'section [of the NIMT] from Taihape to Waiouru was largely his creation.' After the completion of the NIMT Harding held several other PWD positions around New Zealand before his retirement in 1926. John Davinci Louch (1854-1937) Born and trained as a surveyor and engineer in Ireland, Louch immigrated to New Zealand in 1875. He initially worked as a PWD surveyor and then engineer in the northern North Island. In 1901 he was named Resident Engineer in charge of completing the NIMT from the northern end and held this position until the railway was completed in 1908. Late in that same year Louch was appointed the District Engineer of Wellington, a position he held until his retirement in 1920. Peter Keller (1880-1961) Keller was born on the West Coast of the South Island and is said to have been a protégé of Richard Seddon. Keller was an up-and-coming cadet, and then assistant engineer, involved in the construction of the NIMT between 1902 and 1908. He was mostly engaged around Taihape and then Raurimu, and as such worked on sites and structures including the Turangarere Horseshoe, the Raurimu Spiral, and the Makatote Viaduct. After the NIMT was finished he worked in Westland, Central North Island, and Taranaki. When he retired in 1943 Keller was the District Engineer at Dunedin. SURVEYORS: John Rochfort (See DNZB entry) PHYSICAL DESCRIPTION AND ANALYSIS: This NIMT Historic Area winds, climbs, and stretches over the narrow NIMT railway corridors of the central North Island, between a southern point of the Makohine Viaduct and the Taumarunui Railway Station to the north. The NIMT construction era line and subsequent deviations within this historic area encompass an approximately 200km long route. The form of the NIMT in the central section is largely defined by the topography in which it is situated. The vicissitudes in the landscape through which it passes over and through are evidence of the long history of the area's volcanic activity and violent upheavals, and the natural gouging progress of numerous waterways. From the south and north, the railway climbs towards its middle in the Central Plateau, and as it does it travels through farm, hill and tussock country, forests, over deep gorges, past some of New Zealand's most spectacular mountain scenery which allows views of Ruapehu, Ngauruhoe, Tongariro and sometimes Mount Taranaki in the distance, and beside and over several significant rivers; areas which are sparsely populated with the exception of the small towns which dot the NIMT and mark its progression for rail passengers. It is the diversity and drama of the landscape which makes the central part of the NIMT the aesthetic highlight of the long train journey from Wellington to Auckland and one of the most impressively scenic areas in New Zealand whether travelling by rail or road. Beginning from the Makohine Viaduct at the southern end of this NIMT Historic Area, the railway's ascent towards the Central Plateau begins to be more pronounced. The crossing of the Rangitikei valley by way of the 1981 deviation is relatively level and the deep crevasses of that river and others are navigated with a close succession of viaducts which culminate with the deviation rejoining the NIMT construction era route just south of the Toi Toi Viaduct near Utiku. To the west of the deviation the NIMT construction era route rose and fell sharply north of the Mangaweka Viaduct and through a series of tunnels. With this area's redundancy from the functioning NIMT it has been subsumed into the surrounding farmland [to some extent, although the fomation is still easily discernable and the tunnels survive]. From Taihape there is the long climb to Waiouru, beginning at a grade of 1 in 60 but largely at 1 in 70 from Mataroa to Hihitahi. The serpentine nature of the railway in this area is dictated by the Hautapu River which it either runs parallel to, or shadows throughout the Turangarere and Waiouru Sections. The grade also influenced the form of the corridor and necessitated the creation of the Turangarere Horseshoe to make it traversable. Waiouru Station was the highest railway station above sea level in New Zealand, which is indicative of the extent of the climb to get to it, as is the view which is dominated by the mountains. The railway from Waiouru to Ohakune is mostly characterised by a descent. Although following a predominantly straight course through Karioi and Rangataua, between Waiouru and Tangiwai is a sinuous section of track which has been noted as a speed trap and was the scene of the 1981 Silver Fern railcar derailment that killed four passengers. This section also features the Tangiwai Memorial Reserve on the banks of the Whangaehu River. North of Ohakune on the generally 1 in 60 gradient climb across the western flank of the Waimarino Plateau, the railway is punctuated by a close succession of viaducts and bridges crossing the numerous rivers and streams that flow down from and around the mountains, including the Manganui-o-te-ao River. Aside from the area between Ohakune and Horopito which cuts through the Tongariro National Park, the railway in this area is generally flanked by SH4 on one side, and the national park on the other. This area is the site of the Ohakune to Horopito Deviation as well as the line of the NIMT construction era route and the Ohakune to Horopito Coach Road which are also included in this NIMT Historic Area. Many of the features of the old corridor can be seen from the present functioning NIMT. Then, again with a few exceptions, the NIMT follows a straight north to north-eastern course until it reaches Raurimu and the famous Spiral. From National Park there is a long, steep descent off the Central Plateau with numerous curves down through Raurimu and Owhango to Kakahi, and an easier descent beyond this to Taumarunui. On the approach to Taumarunui at the northern end of this historic area, the NIMT follows the route of the Whanganui River closely before passing through Manunui and eventually across the river just south of Taumarunui Railway Station. This Historic Area features a selection of historic places which are linked by their NIMT use, ex-use, or closely related purpose and site. Key components of the historic area include specially engineered or architecturally designed railway structures and places along the NIMT construction era and current NIMT route such as bridges, buildings, significant earthworks, a road, tunnels, and viaducts. The continuity of view which the railway provided or currently affords, which incorporates the two adjacent commemorative reserves, is also an important feature. As well as the representative or exceptional structures and sites included as places within the historic area, there are innumerable subsidiary railway construction components and operational devices within its boundary such as culverts, cuttings, embankments, level crossings, underpasses, electrification and signalling paraphernalia, and the track itself and what it rests on, to name but a few. As this suggests, a railway is an intricate combination of many physical components which would be impractical to catalogue and assess in great detail for heritage values because many of these features, by their nature and for the smooth operation of the railway, are meant to be relatively temporary, or else they have been assessed as not being sufficiently significant contributing factors to the development and history of engineering and railways in New Zealand, or to the history of the NIMT, to warrant inclusion as places in the historic area. While not being dismissive of these components the places highlighted within this historic area are those which are generally considered representative of the developments in the engineering and railway history of New Zealand and contribute to this story, or those which are recognised as places of heritage value on their own merits. Railways, and the structures and sites within them, are typically built and operated based around the principle of continuous improvement and repair when needed. Therefore additions and alterations within this NIMT Historic Area are an integral part of its story and are representative of larger historical changes in railway operations and technology. The main periods of change include: bridge strengthening and other changes [during the late 1920s-1930s in preparation for the introduction of the K class locomotives], assessments of the economic viability of NIMT construction era bridges and subsequent upgrades or replacement, as well as the introduction of new operational technologies and centralisation which saw the closure or downsizing of stations from the 1960s, and finally, the electrification project during the 1980s. Over time, the general types and uses of fabrics within the NIMT did not change dramatically until the mid to late 20th century when the use of concrete took precedence. The use of concrete in the construction of the bridges and viaducts, a conscious policy in effect from the 1960s, was ultimately in aid of reduced maintenance costs and prolonging the functional life of the assets. The use of concrete is a key distinguishing factor between pre and post-1960s bridges and viaducts in this area. Concrete was used in NIMT construction era bridges and viaducts but was restricted to the footings, smaller piers, and abutments, with preference for steel trusses and plate girders in construction, with a few examples also featuring timber in their superstructure which has all needed to be substituted with more durable materials, or the entire structure replaced. Concrete was also used for lining the NIMT construction tunnels and culverts, and in recent times sleepers have been manufactured in concrete rather than the traditional timber. The youngest railway station in the area, the Taumarunui Railway Station, had concrete used in its construction, which is a departure from its timber built and clad NIMT construction era predecessors. The electrification project facilitated the most significant change in the form of the NIMT in the central North Island. Aside from the comprehensive installation of the electrification equipment and some alterations to tunnels, which included the lowering of floors and the creation of more services refuges, electrification also necessitated the only two major deviations away from the NIMT construction era route. In the case of the Mangaweka to Utiku Deviation, the repositioning of the rail corridor occurred because the Mangaweka Viaduct was no longer viable, and the collective of tunnels, reasonably heavy grades, and sinuous form of the track was unsuitable for an electrified railway. Although some heavy cutting and the immense embankment at Blind Gully were needed, as well as three major viaducts, the deviation route could achieve a relatively level and direct route in comparison. Likewise, the Ohakune to Horopito Deviation reduced the unnecessary tight curvatures of the existing route and the new Hapuawhenua Viaduct replaced the ailing NIMT construction era counterpart. Land included in the Registration: This NIMT Historic Area covers a long and narrow area defined by the past and present designated NIMT railway corridors within the thematic physical southern and northern boundaries of the Makohine Viaduct and Taumarunui Railway Station. The land in the area also includes recognised NIMT related places which are not part of the railway corridor, but are immediately adjacent to it, such as the land incorporated in the extents of the two commemorative sites and the Ohakune to Horopito Coach Road. It is important to acknowledge the vast range of places on or directly related to the NIMT between Wellington and Auckland which for thematic reasons are external to the land and sites included in this historic area. For instance, none of the 'railway towns' with their collections of railway worker cottages, or the many private sidings which branch from the NIMT, have been included in the area's extent despite the contribution they could make to a holistic history of the NIMT and its effects. Places of note external to the extent of the area or theme have been listed in a file note. Historic Places on Land included in the Registration: 1. Makohine Viaduct, Vol. II, Appendix 5.4.1, page 6 2. Mangaweka Viaduct footings, Vol. II, Appendix 5.4.2, page 9 3. Toi Toi Viaduct, Vol. II, Appendix 5.4.2, page 12 4. South Rangitikei Viaduct, Vol. II, Appendix 5.4.3, page 17 5. Blind Gully Embankment, Vol. II, Appendix 5.4.3, page 20 6. Kawhatau Viaduct, Vol. II, Appendix 5.4.3, page 23 7. North Rangitikei Viaduct, Vol. II, Appendix 5.4.3, page 26 8. Mataroa Tunnel, Vol. II, Appendix 5.4.4, page 30 9. Turangarere Horseshoe, Vol. II, Appendix 5.4.5, page 34 10. Whangaehu River Bridge, Vol. II, Appendix 5.4.7, page 41 11. Tangiwai Historic Reserve, Vol. II, Appendix 5.4.7, page 44 12. Ohakune Railway Station and Signal Box, Vol. II, Appendix 5.4.8, page 47 13. Ohakune to Horopito Old Coach Road, Vol. II, Appendix 5.4.9, page 48 14. (Old) Hapuawhenua Viaduct, Vol. II, Appendix 5.4.9, page 49 15. Taonui Viaduct, Vol. II, Appendix 5.4.9, page 51 16. (New) Hapuawhenua Viaduct, Vol. II, Appendix 5.4.9, page 54 17. Mangaturuturu Viaduct, Vol. II, Appendix 5.4.10, page 58 18. Manganui-o-te-ao Viaduct, Vol. II, Appendix 5.4.10, page 59 19. 'Last Spike' Memorial, Vol. II, Appendix 5.4.10, page 62 20. Makatote Viaduct, Vol. II, Appendix 5.4.10, page 63 21. National Park Railway Station, Vol. II, Appendix 5.4.11, page 66 22. Raurimu Spiral, Vol. II, Appendix 5.4.12, page 71 23. Piopiotea Stream Bridge, Vol. II, Appendix 5.4.12, page 72 24. Matapuna Bridge, Vol. II, Appendix 5.4.13, page 76 25. Taumarunui Railway Station, Vol. II, Appendix 5.4.13, page 77 Relationship between Historic Places: These places are NIMT construction era sites or are places subsequently constructed which are, or were, part of the functioning central section of the NIMT, or are NIMT related places immediately adjacent to the railway within the area bordered by the Makohine Viaduct and Taumarunui Railway Station. With the exception of the commemorative sites, the places in the historic area were all constructed to have the railway track running over, through, or directly adjacent to them and had their designs and construction sanctioned by the PWD or NZR. The completion of construction of all these places date from 1900. Key Elements of the Historic Area: A key element in this historic area is the linear, undulating, view shafts created by the rail corridors and their associated earthworks which also often open to afford comprehensive views of the surrounding landscape especially when crossing bridges. The adjacent scenic or historic reserves contribute to this too. Other important elements include the early 20th century tunnels, and concrete and steel bridges or viaducts, the mid to late 20th century concrete bridges and viaducts, and railway stations and associated buildings and yards.