NEW ZEALAND'S GREAT ENGINEERING WORK: Arthur's Pass Ttinne

Progress, Volume II, Issue 11, 2 September 1907, Page 414

NEW ZEALAND'S GREAT ENGINEERING WORK:

Arthur's Pass Ttinne

The history of this railway project, for connecting the east and west coasts of the South Island, goes back as far as that of any New Zealand railway. Like the others, in fact. this project goes back to the original list of the Public Works Scheme of 1870 In those days imagination was boundless, and it

was not thought extravagant to plan a trunk line along the west and east coasts of both islands, with cross lines between. The cross line joining the two coasts of the South Island was especially in favour. It was the fashion to speak of the riches of eastern agriculture and the wealth of the mines and forests of the west interchanged to the mutual advantage of the populations ; neither was it deemed

unlikely that a ferry from Nelson to Wangarmi would carry the passenger traffic of the south comfortably and rapidly on its way to Auckland. These things were dreamed when men had not thought out the problem of railway construction They were cherished before a department of construction had been organised. They were on paper in the usual perfunctory manner when there were few engineers in the country who understood railway construction. When the department of construction was organised and the plans of engineers, the works of contractors, and the immigration of labourers took the place of hopeful comment and facile dreams, the more difficult of the railway works took second place, and the lines offering the chief engineering difficulties dropped out of the running altogether. In this last category came the great trunk lines of the east and west of the South Island and the great cross line for connecting them together. The precipices, the glaciers, the torrents of the great "Divide" frowned on the once easily accepted cross line, and with them frowned the politicians made wary by responsibility of the loaned millions. That was the second stage of the cross line for connecting east and west in the Island of Te Wai Pounamu. But the men of the east and west, the men of North Canterbury and the men of Westland and the men of Nelson, frowned back at the precipices and the politicians, and, being practical men withal, they very soon organised themselves into leagues. The leagues collected statistics, raised moneys, hurled deputations at Governments, built the fires of political agitation, and a livery energetic stubborn press fanned the flames. To tell the story of the long fight which ensued would be as wearisome as the conflict itself. It would, moreover, be a waste of space which is required for the story of the great tunnel through the big " Divide." It is enough to say that the agitation, after overthrowing more than cne Government, succeeded in getting the cress line taken up by a private company, with the assistance of grants of the public lands on the line or in its vicinity ; that the company, after constructing most of the western portion of the line, found itself unable to go

on; that the Government took possession and prosecuted the work : that the company and debenture holders were dealt with justly, even with liberality ; and that ultimately, after an interval of the wry face and the loud protest, echoes of which even penetrated to the Stock Exchange, they recognised the fact.

The line is made on the east side to Broken river, connecting that place with the town of Springfield, the outside station of the Canterbury section of the southern railway system On the west the line is in working order from Reefton to the Otira, with a branch connecting with the old government railway at Brunnerton. The tunnel through

Arthur's Pass is the link between the sections of the Midland line — as the cross line has been for years called. The work of constructing it has just been let to the Messrs. McLean-, and the Government is completing the line from Otira on the west, and from Broken river on the east, to the west and east ends of the tunnel as fast as it can.

The tunnel was not always in the minds of the engineers of this line. In the beginning, as soon as men began to realise the difficulties before the cross project, they felt that, if possible, they must eliminate the enormous cost of a summit tunnel True, any system of crossing the mountains instead of piercing them would be expensive for all time. Still, by concentrating the heavy haulage in the centre and keeping the grades flat on both sides they thought it might be possible to make a profitable line. The Abt and the Fell systems had each their advocates. For a time the war between them raged high. At last the matter was referred to experts, and it was definitely settled that the cost of operating either the Abt or the Fell system at Arthur's Pass would be extremely high, that in fact, as neither of these presented any escape from the bulk of first cost, they would both be extravagantly expensive in operation. This conclusion received later on the cordial approval of Mr. Bogue, the very capable and experienced American constructing engineer who reported on the whole question of the tunnel through the Pass. It was in 1902 that Mr Bcgue undertook the task of pronouncing on the various schemes recommended by the Commission for piercing the Alps with a tunnel. He went thoroughly into the subject, and reported in favour of the construction of a line with modefately easy gradients approaching the " Divide," concentrating the heaviest works at Arthur's Pass, and piercing the range by a long summit tunnel. Mr. P. S. Hay, the late Engineer-in-Chief of the colon)^ who was one of the Commission of Engineers referred to above, and who had accompanied Mr. Bogue in his examination of the country, also reported on the problem, suggesting a

slight modification of Mr. Bogue's line with a considerably longer summit tunnel. Mr. Bogue subsequently concurred, and the suggestion was ultimately adopted. Mr. Hay accordingly prepared the plans and specifications for the tunnel. The geology of the Pass is thus described in a memorandum of the Government Geologist, Mr. Alexander McKay, at the request of Mr Bogue, Which is as follows • — Wellington, 15th February, 1902. Sir — " At the request of Mr. Y. G. Bogue, CE , I have the honour to forward 3^ou for his information some account of the geology of the Arthur's Pass and the mountains through which the Otira Gorge has been cut. "' Approaching Arthur's Pass from the east, the rocks are alternations of sandstone and shales that are either of Permian or Carboniferous age. \.^j " The general dip is to the north-west, and, apart from surface slips (which are not common), I anticipate they will form good standing ground on being mined or tunnelled into. " On Arthur's Pass the dip changes to the south-east, and there is also some change in the character of the rock, the bare sandstone expanding to a much greater thickness than what shows along the Bealey river. There is an absence of deep sagging slips, and from the Bealey to the Otira the rock should prove

sound and safe driving-ground, at even an inconsiderable depth from the surface. The principal rock is a hard, grey, or greenishgrey, sandstone, with which are associated bands and thick masses of dark slaty shales, and there is an absence of the greyish, drossy, and pulverent thinbedded shales and sandstones which have proved so troublesome (as running ground) in the neighbourhood of Wellington, and in the Rimutaka and Ruahine ranges. At the upper end of the Otira Gorge the rocks revert to the thinner-bedded sandstone sand shales, but continue to be good standing country, as proved by the siding at the road at Cape Horn, in the deeper part of the Gorge. The same character of rock continues to the west end of^the Otira Gorge and the junction of Rolleston Creek with the Otira. " On the crest of Hill's Peak a fissure of great depth has been formed, and this is by some regarded as an extended earthquake fissure. Whatever it may be, for I have not examined it, there is no indication of its being continued in depth to the level of the Otira above the zig-zag, nor continued in the mountains on the west side of the Gorge and upper valley of the Otira. At the time of examining the district, I had discovered most of the great fault-lines that run to great distances

along both flanks of the Southern Alps, and had there been any such signs on Arthur's Pass, or along the Otira Gorge, I had not been

slow to detect and note the same. " As the rocks of Otira Gorge and Arthur's Pass are the same in age and character as the auriferous Maitai rocks of Reef ton, the opinion of some of the mine-managers might be sought with respect to the standing quality of the rock in which they carry on mining operations. " In Kellys Ridge there is a change to a preponderance of black, slaty rocks, the sandstones being less abundant than farther to the east Up Kellys Creek these form high vertical bluffs that exhibit the characteristics of good standing country. Alex. McKay, Government Geologist. " Hon. the Minister of Mines."

The tunnel is 5 miles 25 chains and 12 feet long. It enters the " Divide " in the valle}^ of the Rolleston (see plan herewith) at an elevation of 1585 feet above sea-level on the western side of the Pass, and emerges near the Punch Bowl on the eastern side, at an elevation of 2535 feet, the Pass rising about

midway between these points to a height of 3000 feet. The line constructed as far as Broken river, through some very rough country, attains at that point a level of 1406 feet above sea-level and is under construction towards the Bealey, the route crossing the Waimakariri near the jvmction of the Cass with that river, at a point where the river bed narrows opposite the well-known bluffs. From the western side the line has been pushed on to Otira, which is 1255 feet above sea-level Approach works are included in the tunnel contract, the length of country covered by which is in all about eight miles, and besides the actual tunnel construction there are cuttings, banks, protective works, and service roads to be provided for. The grade in the tunnel and the approaches is 1 in 33, and uniform throughout the entire length The tunnel itself will be 15 feet 6 inches high, 14 feet wide at rail level, and 15 feet at its widest point, 6 feet 3 inches above rail level, lined at the sides with rubble masonry, concrete or brickwork, and with concrete blocks or brickwork in the arch.

It is interesting to compare the lengths of the longest tunnels in the world. The seven longest are • — (1) Simplon tunnel, between Western Switzerland and Northern Italy is 12-^ miles in length. (2) St. Gothard tunnel penetrates the Alps between Italy and France, and is 9J miles long. (3) Mount Cenis tunnel is 7.9 miles long. (4) Arlberg tunnel, Austrian State Rpilways, Vienna, is practically 6^ miles long. (5) Arthur's Pass tunnel will bes^-mileslong. (6) Hoosac tunnel, on the Fitshburg R R. in Massachusetts, is practically 4f miles long. (7^ Graveholz tunnel, on the Bergen railway, in Norway, is the longest tunnel in Northern Europe, and is just upon miles in length. It is apparent at a glance that the Arthur's Pass tunnel, the fifth on the list, is longer than anything in the North of Europe, and heads the tunnels of the world, with the exception of the four famous tunnels in Central Europe. The comparison of grades is even more favourable to the New Zealand enterprise.

In America, on the Atchison, Topeka, and Santa Fe Railway, the ascent to Raton tunnel, at the summit of the Raton Mountains, has a maxium grade of 1 in 28 6-10ths, or 185 feet per mile. Between Salt Lake City and Denver the ascent to the tunnel at Soldier Summit of the Wahsatch Mountains, on the Denver and Rio Grande Railway, has a maximum grade of 1 in 25, which is practically continuous for seven miles. On the Colorado Midland Railway, another important line, which crosses the Continental Divide at the Hagerman two -mile tunnel, the maximum grade is about 1 in 24. Between San Francisco, California, and Portland, Oregon, the ascent to Siskiyou Tunnel, at the summit of the range, of which Mt. Shasta is a part, has many miles of 1 in 30 grade, the curves having a minimum radius of 6i chains. These are a few of many instances. They are important because of the vast traffic which annually passes over them. In Mexico there are other numerous instances of the use of such grades, the most notable, perhaps, being that of the Vera Cruz and Mexico City Rrilway, the English line, upon which the minimum grade is 1 in 25. In -South America there are few. if any, lines of any considerable length where there are not, more or less, maximum grades of from 1 in 331 to 1 in 25. In Europe the ascent to Mount Cenis tunnel has maximum grades of 1 in 33J, while that of St. Gothard is 1 in 38*. In the effort, therefore (to use Mr. Bogue's words), to conform with Nature's topographical features rather than to attempt to cut this down to some Procrustean rule, New Zealand will be doing what is done in all other parts of the world. The amount of the tender is £599,794, and the successful tenderers are Messrs. McLean Brothers. The other tenderers were Messrs. Kirkwood, Kerr, and Co , of London (£688,216), and Mr. J. Drummey, of Arrowtown, Otago, (£628,732). Evidently the work did not prove too attractive to the tendering public, which was systematically appealed to in Britain and Australia It is matter for congratulation that two out of the three tenderers were New Zealanders,

The successful tenderers, Messrs. McLean Brothers, have had considerable experience of a varied character, extending over many years. Their father, with whom they learned their business, was a well-known contractor, and between them they have covered forty years of construction service. The tunnel tenderers have to their credit the Auckland tramways, a large portion of the Wellington harbour works, a section of the Rotorua railway, the Kanohi section of the Northern railway beyond Helensville (celebrated for the

most difficult tunnel ever built in New Zealand), haibour works at Westport (with wharl and staiths for working coal), and they built the bridge at Inangahua, and the famous Buller bridge. In consequence of trouble over their tunnel contract at Kanohi, they were obliged to petition Parliament and they obtained a favourable verdict from the committee set up to investigate their claim. It speaks well for the calibre of the New Zealand bred contractors that this firm was able, out of its own experience, to tender for a work _£ -L .„ Zi. 1« A AlCC~* !•(-„ -,^ 4-Un /^H-im

tunnel. That is a fact worth pondering, for it throws a great light upon the development of engineering construction in these islands. One of the firm proceeds to London shortly in quest of the necessaiy plant. It is suggestive that when the Provincial Government of Canterbury decided to make the tunnel through the hill between Lyttelton and Christchurch, that work was considered one of the foremost of its kind in the world. The London firm of engineers that undertook it, subject to examination of the ground, were discouraged by the hardness and what they took to be the extent of the rock formation, and after working some time vainly on the hard rock, decided not to proceed. Luckily there happened to be present in the colony a yo -ing geologist who had been appointed to the position of Provincial Geologist at Nelson at the recommendation of Dr. yon Hochstetter (scientific head of the " Novara " expedition) who was in the colony at the time writing that fascinating and valuable treatise of his which did so much to reveal the resources of this country to its people. This young geologist, Dr. yon Haast, afterwards fa -nous as Pro\incialGeologist of Canterbury, was sent for by the Canterbury superintendent, the late W. Sef ton Moorhouse, to report on the hill between Christchurch and I/yttelton. He discovered the hill to be the wall of an old volcanic crater, and reported that though hard rock undoubtedly abounded in the formation, there \\ as nevertheless much ground of a character easily worked. On that report Messrs. Holmes and Richardson, of Melbourne, who had built some of the Victorian railways — very fine specimens of railway construction they are to the present clay— undertook the Lyttelton tunnel and duly bored the same. During <= O me of the Saturday nights after work was over Dr. yon Haast used to proceed to the workings to study the volcanic formation. The result is now in the Christchurch Museum in the shape of a remarkable and most interesting map showing a ] l the strata, the only drawings we believe extant of a boring through a volcanic crater. The only other instance in all history of the piercing of a crater wall is, we believe, that of the tunnel which in early

Roman times drained the Alban lake. But it is unlikely that any drawings of the strata pierced are to be seen to-day. The contractors found some very hard rock on their way through the hill, and had great difficulty in getting steel hard enough for the boring. Shipment after shipment of tools proved useless, but in the end they succeeded in getting the tunnel through. Mr. Richardson, one of the firm, proceeded to London during these difficulties in search of better steel, taking with him blocks of rock, on which to try the steel, for the making of which he invited competition. Some of these samples were of rock that had absolucely defied the steel in use in the tunnel, and some had required the waste of three feet of steel for every foot of stone. When in London inviting the competition, Mr. Richardson found representatives of the Mont Cenis tunnel on the same quest. The rock of th.c Alps, a limestone, 'was softer than that met with in the Lyttelton tunnel, offering obstacles which were child's play in comparison, but it had brought the work to an absolute standstill, so inferior was the steel made for the European undertaking. W. Beardmore & Co. . of Sheffield, were the successful competitors, with a special quality of steel which effectually disposed of the hard rock in the Lyttelton tunnel. That appeal direct to the manufacturers was a resourceful move worthy of the men who made New Zealand. The tunnel was a great triumph of engineering skill at the time — one that made its

mark in the history of the engineering construction of the period. Today how different, with the hydraulic drills and the compressed air motors, the dynamite, guncotton, and diamond drills, which have made possible such works as the tunnels through the Simplon and the St. Gothard. The I^yttelton tunnel is 1 mile 55 chains long, and is large enough for a 5' 3" rail track, and cost about £200 : 000. The works proved a famous training school for engineers, and a large number of the staff of Messrs. Holmes and Richardson afteiwards took a leading part in the railway works due to the Public Works policy of 1870. The plans of the Lyttelton tunnel were drawn by the late E. Dobson, then Provincial Engineer, who was also designer of the famous West Coast road over the Arthur's Pass, one of the boldest works ever conceived in this country. The construction and"~supervision were due to the Honourable E Richardson, whose conspicuous abilities were then devoted for the first time to the service of this country, in which they have done royal work during the years that have passed since that eventful period of our history. It is to his experienced skill, prudent foresight, and organising energy that a great part of the success of the Public Works policy was due, in token of which fact Mr Richardson is acknowledged by every man of capacity to have been the very best Minister of Public Works in our history. Trsined as a civil engineer

on the London and South- Western railway, and as a mechanical engineer on the Great South- Western railway of Ireland, he attained eminence in both capacities. Therefore, jt was that during his five years' service as Minister of Public Works— lß72 to 1877— he laid the foundations of our railway system which is distinguished on the one hand by the magnificent railway workshops of this country equal to every kind of work, and, on the other, by the splendid staff of constructing engineers of the service who, trained in the Department, have designed and carried out some of the finest railway works south of the Line. The organising work of those early years, during which everything had to be improvised under great difficulties, broke down Mr. Richardson's health and he had to retire in the last-named year. He served again in the same capacity in the Stout- Vogel administration from 1884- to 1887. To return to the Otira tunnel. The locality in which the tunnel will be bored is a national scenic reserve, and the contractor and his workmen will be compelled to carry out the work in such a way as to cause no damage to the forest scenery or permanent disfigurement of the landscape. Provision is also made in the specification for the care and housing of the workmen to be employed, as the winter climate at the elevation of the tunnel is rather rigorous. Investigations are being made as to the possibilities of utilising with advantage the water powers of the colony for the generation of electrical energy on a large scale, and the conditions in various places seem eminently suitable. It is probable, therefore, that by the time the tunnel is completed, the authorities will be in a position to substitute electric for steam traction in running trains through the tunnel, thus minimising the inconvenience to passengers which would be inseparable from a five mile tunnel journey behind an ordinary steam locomotive, even with modern devices for the abatement of the smoke nuisance There is, of course, some doubt on this score, for the water in the rivers about the summit is very low at times. During the summer season there is an abundance, but in winter there is only a trickle. The Department is inclined to the opinion that even in winter this water can be concentrated in the upper gorges before the rock formation is succeeded by shingle. They may be right, but the question has to be left to the test of experience. The contractors are investigating. Work on the western side will be easier as may be seen from the fact that the tunnel level of 1 in 33, is uniform. The tunnel will be worked from both ends ; and would be worked also at points between, if there was possibility of "getting economical adits from the sides so as to establish more faces and get the work through quicker. But it is feared that there is no hope in this direction. Thus the work at the western end will be down hill and that at the eastern will be the reverse — a great matter in the haulage of the * spoil, and the drainage of the incidental water. "Moreover, the railway works are close up to the western approaches to the tunnel, whereas on the east there is nothing nearer than Broken river, the present railhead. Further, the rivers on the west are bridged close up to the tunnel ; whereas those on the other side are not, and the country is difficult. However, all these matters have been taken into consideration by the contractors, whose work on the east side has been facilitated to some extent by the right to build a temporary bridge over the Bealey

for which, they are to be paid. It has been said that it would have been better to have made provision for a permanent, not a temporary bridge in this contract. But that is just a matter of opinion, and the question has been decided probably with due regard to the despatch of the work, and calculated accordingly. The probability is that the eastern section of the workings will be 2J- miles, the western accounting for the balance of 3§. According to the contract, the whole must be finished in five years. The set off for delay is £280 per week, the deposit is £12,000, and the bond is for £50,000 : while the rates for progress payments are 90 per cent of value of work done, and 50 per cent, of value of materials. Will the line pay ? That is the great question. It is in a sense academic, because the country will have the line at work in five years, if all goes well ; and with contractors like McLean Bros, all will go well, we may surely hope. Now the cost of the line will be, say, £1,500,000. At present rates for railway haulage of timber and coal there is a margin in favour of the railway of Is 5d for timber r-er foot, and of 4s 3d per ton for coal. In the following estimates the total from the present traffic (steamer) from these two sources of revenue assuming that the railway gets the whole.

would, at the present railway rates, be £56,000, as the Midland Railway Committee of Canterbury points out. Then we ha\e to assume that the merchandise would all be taken by the railway also Passengers have to be guessed, and we take here the estimates that have been current for twenty years past, the prospect of the tourist traffic being admittedly good. Sundries are the same The estimate then comes to this : — Coal and timber, £56.000 ; merchandise, £30.000 ; passengers, £25,000 ; sundries, such as mails, sleepers, building stone, and live stock, £22,000 : total revenue, £133,000. This seems to work out to an approximation of the average earnings of the railways of the colony which is about £1,000 per mile. Assuming the working expenses at 70 per cent, there is a profit on the estimate of £39,900, which approximates to the £45,000 of interest, 3 per cent, on the cost. Which looks rosy enough on paper, especially considering the developments to be expected from the working of the line regularly On the other hand the assumptions are,

well, they are assumptions of a large order. The steamers are not going to take it lying down. Neither are the merchants of Wellington, who are supplying most of the merchandise now. The factors in favour of the railway are ; the fact that coal taken by sea undergoes three handlings ; that the source of timber traffic is nearer to Christchurch and Ashburton than the distance in the estimate, which is the 140 miles between Brunnerton and Christchurch ; that grain and agricultural produce will probably go direct from Canterbury; and that there is a great likelihood of the output of timber increasing from the Ross side and keeping up the supply for many years. Moreover, it is generally admitted that the greater promptitude and regularity of trade guaranteed by railway traffic is an advantage of decided character. Allowing for these favourable factors to the most liberal extent possible, it is still evident that as to the ultimate profit there is an element of uncertainty which only time can solve. Possessing the line, the colony has to make the best of it, and ought to regard the future of the most magnificent engineering work outside of Central Europe with all the hope it can muster for the task of its energetic development. Note. — Arthur's Pass was named after Mr. Arthur Dudley Dobson, now City Engineer of Christchurch. Its discovery and selection for the famous West Coast road are told in the following interesting passage from Haast's " Geology of Canterbury and Westland." Of the expeditions exploring the head waters of the northern rivers, that of the late George Dobson, C.E., was most successful, he amongst others discovering Arthur's Pass, a deep depression in the central chain leading from the sources of the Bealey, one of the upper tributaries of the Waimakariri, into the Otira, a large branch of the Teremakau. After this important discovery had been reported, the Provincial Government lost no time, and sent Mr. E. Dobson, CE-, formerly Pro\incial Engineer, and at that time resident engineer of the L,yttelton and Christchurch railway, to examine this and some of the passes found about that time, with full authority to place the necessary work at once in the hands of the contractor. Mr. Dobson, after inspecting two passes at the head of the northern main branch of the Waimakariri, Harman's Pass and the socalled Browning's Saddle, and another saddle at the head of the Hawdon stream, selected Arthur's Pass as affording the most favourable physical conditions for a road between both coasts, and the work was at once taken in hand and pushed on with great energy The cost of stopping a train ranges from 2s for a train of ten ordinary passenger coaches, to 6s 8d for an express train of heavy corridor-cars four times the weight of the other. Where there is an up-grade the expense is more than on a level. The Ormond Beach, in Florida, where so many motor records have been broken is the most remarkable beach in the world The receding of each tide leaves it perfectly smooth and almost as hard as asphalt, making an ideal course for motor racing. Scheelite to the value of £3407 was exported from New Zealand last year. Eighteen tons were exported to the United Kingdom, the value of which is set down at £991, or about £55 per ton, and 37 tons to Germany valued at £2416, being at the rate of nearly £65 6s per ton.