WELLINGTON TO AUCKLAND

New Zealand Times, Volume XXVIII, Issue 5864, 3 April 1906, Page 7

WELLINGTON TO AUCKLAND

MAIN TRUNK RAILWAY. THE NORTHERN SECTION. A STUMBLING-BLOCK. TV. Looking at the Main Trunk Railway works to-day from any point of view, ono must come to the conclusion that the hulk of the difficult work is in the northern section. ana that any delay in completing tho lino must be looked for in that quarter. It Is true that tho mileage of unfinished line in the northern section is shorter than in either of the other two, but tho character of the unfinished work is entirely different, and tho difficulties ahead cannot bo compared. SLIPS AND WASHOUTS.

The end of the railway from Auckland, so far as tho Railway Department has any knowledge, is at Taumarunui, whoro tho line strikes the Wanganui river. This is 175 miles from Auckland, 137 from Marton, and 253 from Wellington. Up to this point the difficulties of construction on the ninety miles of lino from Frankton Junction southward were largely confined to tho hard rock tunnelling at Poro-o-tarao. The lino has now been completed for a distance of twenty miles southward of Taumarunui, and ballast trains arc running regularly to Oio. This section marks tho commencement of the long up-grade from the basin of the Ongaruo, a tributary of the Wanganui. to the Waimarino plateau. The Wanganui river, emerging from the.tarns of Tongariro, attains some proportions before it reaches Taumarunui in its northward course. During this part of its career it is a source of continuous anxiety to the railway builders. About half-way between Taumarunui and Oio there was a good deal of very heavy cutting, rendered doubly difficult by the treacherous nature of the soil. Time after time huge cuttings fell in, and the whole of tho work had to bo done over again. In one case an engine had just passed through a cutting when tho sides slipped in, filling the cutting almost completely. Now and again tho earth slipped so persistently that tho surveyed route had to be sl'ghtly deviated from, and another cutting made. Ono cutting that had held up without any signs of slipping for twelve months suddenly gave way, and buried the works. Even to-day, though the sides of the embankments are overgrown with tutu, the engineer (Mr Louch has not ceased to be anxious as to their security. About half-way along the Old section half a dozen huge groynes in tho Wanganui are signs of the efforts made by the engineers to save the lino eighteen months ago, when the flood-waters made dangerous inroads on the banks below. The river on that occasion shifted its main ■ channel right across from the east, to the west side of the bed, and threatened to carry away the whole formation for several chains. It is considerations of this kind, quite unforeseen, that cause delay in the prosecution of the work.

Between Taivmarunui and Oio there are several bridge works of some importance. These include the Matapuna bridge, close to Taumamnui; the Waitea bridge, consisting of one span of 32ft, four of 33ft, 'and one of 44ft ; and the Kakahi bridge, five spans of 44ft and one of 23ft. The material for the Matapuna bridge was supplied by Scott Bros.; of Christchurch, and that for the others by Fraser and Co., of Auckland, ™e department erecting all the bridges. And so the line is completed, and laid with 701 b rails as far as Oio. i.e., about 117 miles from Marten and 195 from Auckland. The last section of twenty miles is being worked by the Public Works Department. Ballast trains are continually running up and down the line, and special trains are also run daily to take the children of the construction men to school. Passengers are carried on the usual conditions for such pieces of line, the coach service from Oio connecting and extending as far as Makatoto. THE SECTION IN HAND. From Oio to Baurimu, a distance of fire miles and a half, the formation is more than half done, and the bridgin'* works are in hand. Just after leaving the Oio station _ the formation was completed, but a, slip occurred which necessitated a deviation and alteration of the grade. A mil© from the station there is a very largo filling, now almost completed, with a water-channel 10ft in dimensions and four chains lone and lined with 14in of concrete. The route then dives into a huge cutting, which attains its greatest depth at 70ft • This is likely. to take another six months to complete, bar accidents. At the end of this cutting is the Waikobatu river to be bridged—and then the formation goes on to the Piopiotea bridge. This will be a steel girder structure 276 ft long, containing one span 'of 80ft and the rest of 23ft. The ironwork is bein'* provided by Fraser and Co., of A uok” land, who are making alTthe bridges in this locality, the department erecting them. Good progress has been mad© with the pdo-dnving, and it is hoped the bridge may he completed in five or six months. The route then follows the To Pure valley for a few miles, down to Baurimu. The formation in the valley is pretty well through, though a start has not yet been made on the small bridge which is to be erected over the Te Pur© creek. On this section a number of concrete culverts was provided for to negotiate small creeks, but it has been found more expeditious to substitute log culverts, which are a great deal cheaper, and servo the purpose quite as well. The work on this section, which is all within measurable distance of completion, brings us up to the station yard at Baurimu (formerly called Pukerimu) where the railhead will probably remain for many months. THE PUKEBIMTT HTT.T.

Ahead of here is a piece of engineering work that will be named with the Rimutaka Incline and the Makohine viaduct, though possibly without the stigma attaching to the former. When the line reaches Raurimu it is imperative that it should negotiate a rise of nearly 2000 ft between that noint and the Waimanno plain, which is less than four miles away. The problem, therefore, is to construct a line between the two points sufficiently long to reduce the grade to a practicable on© for ordinary railway purposes. The grad© decided upon as,„ the .maximum was 1 in 50, and the line had to be- laid off -accordingly.

The grade begins immediately after leaving tho station-yard at ■ Raurimu, tho line describing a horseshoe bond, with a radius of seven chains and a half. It makes two more curves of

similar radius before getting away from the township of Raurimu, then enters a tunnel 418yds long. Before cmerging from this the line begins to curve! again round the hill on what is practically a circle of eight chains and a quarter radius. It enters almost immediately another tunnel 100yds long, and on emerging continues the regular curve, eventually crossing the first tunnel at a higher level, and then striking off towards Waimarino. The figure described by the lino after leaving Raurimu is shown in tho plan below, tho mileage from Marton being marked at each mile-peg:—

At the point where the line crosses itself there is a difference of 74ft between the rail levels. At another point the line in describing the circle is only two chains and a half from the horsefihoo bend, though the actual travelling distance is over a mile and a quarter. The distance traversed from the point at which the grade commences until the line is clear of the circle is two miles and a quarter, although the direct distance is less than half a mile (thirty-three chains). 7 ’ In this distance the line rises 240 ft. The Arline creek is crossed five times. PROGRESS ON THE SPIRAL. In opening up this work the engineers were uatnrnlfy anxious as. ‘to tho kind of formation they would encounter, tho usual experience of tangled layers of volcanic matter being anything but assuring for the commencement of such an undertaking. The bash was cleared, and the approaches for the tunnels prepared, and so far tho result has been very satiel- - The big tunnel was commenced about Ohristmas-time, and has already been driven a distance of 180 ft from the Raurimu end, the formation being of a very satisfactory nature. Large engines will have to bo used on tho < section from’ Tatimarunui up to the Waimarino, and the tunnels are being mad© accordingly; At tho farther end of the large tunnel there is a filling 18ft or 20ft deep over the bed of the Arline creek, and then the lino immediately outers the smaller tunnel. - Some difficulty is being experienced in working these two drives at such close quarters, owing to the' contracted banks of the creek affording no room for disposing of the spoil. At tho mouth of the larger tunnel preparations have been made for washing and screening the spoil, the gravel of which will be used for the cement work. VSater has i;ecn laid on from a higher level for this purpose. Preparations are being made to open out tho shorter tunnel from both ends. Beyond, as the line curves round the hill, there is a cutting 26 obams long, which for seven or eight chains averages over 60ft in height. Then the creek has to bo crossed on a filling which is 100 ft in depth at its deepest. Beneath this there is a concrete oulvort 300 ft long and 2ft 6ln in dimensions, the wails being 2ft thick throughdut. All the stone for this had to be carted along the bed of the creek. From this tiling the line passes through another cutting ranging up to swffc in height at the point where it crosses tho tunnel on the line below. A BIG CONTRACT.

All this work is in hand, and during the summer is progressing rapidly, but it is highly improbable dint the tunnels can bo completed, before the end of the year. With the restrictions and difficulties of the winter at hand there is not much likelihood of to-day's progress being continued very long, and unless the experience of the past is radically altered, the country may congratulate itself if by the end of next summer the permanent way has finitely surmounted the difficulties of the Pukerimu Incline. • After the spiral is passed men are at work right through to the edge of tho bush, six miles from Raurimn, and tho clearing null probably be finished in the course of another month, by which data there should bo men on the formation right through. When the lino reaches tho plains the work will bo very light; consequently it has not been tnought necessary to send gangs on ahead to open up there.

The piers have been commenced for the girder-hndgo over the Piopiotea river, south of Pukerimu; and several other small bridges on high piers have to bo constructed. The ironwork is ready for all these structures up to Makatote, forty miles from Taumarunm.

On the northern section also there has arisen a difficulty in regard to the supply of ballast. So far the gravel has been obtained from deposits at Matapuna, but this is now twenty !u fro ?. the raiihead, and not only will that distance become greater as the ml proceeds, bub the haulage will also become more expensive after Raurimu is passed. Mr Louch is therefore casting about for_ something new, and has ho]>es of finding a suitable gravel deposit somewhere in the Waimarino which will servo that section, and give a down grade for haulage on the Makeretu section. Parties are at present engaged prospecting for gravel on the plateau. SMART ROAD WORK. After crossing the Waimarino Plain southward the route enters the bush again close to the Makokomiho river, and skirting the edge of the hills, reaches the end of the section at the Makatote river gorge, two and a half miles further on. For the last eight miles, that is from the northern edge of the Waimarino Plains, no construction has heen done on the railway at all, the work being confined to the formation of the service road, which will eventually cany vehicle traffic through to Murimutu and Wellington. This undertaking, which it was necessary to accelerate in order to afford tho contractors for tho Makatote .viaduct access to tho site, has been carried out in a most workmanlike and expeditious manner.

Last July the formation and -pumicing, of the road reached only fifteen chains out of Raurimu. Within six months tho road was completed throughout its whole length of thirteen miles to the viaduct, and a fortnight

later the first consignments of material wore delivered on tho siteTlie pumice which is used for roadmaking here has peculiar characterj istics. It is very light, and, being available all along tho roadside, can bo | laid on in almost unlimited quantities at the mere cost of shovelling. A j pumice road is at its worst in summer, • that is, it is very dusty, and somewhat ! loose. But after a shower or two it ! quickly hardens, and, throwing off the water,' presents a splendid floor for traffic. There is now a good full-width pumice road right through from Oio to Makatote, by means of which ma-

terial can he transported from the railhead to the scene of work as easily as along the best macadam road. Tho formation of this highway was in charge of Mr J. MoSinley. and ho has now one hundred men engaged on it, and in cutting a new rock-road across the Makatoto Gorge above the viaduct. Tiiis has been almost finished to its junction with the Valley road on the north side of the Manganui-a-te-ao. It is only necessary now to erect a few bridges and culverts to complete the connection by a full-width and properlyformed road between Auckland and Wellington provinces, and to serve tho bridging and railway works as far as the Manganui-a-te-ao, ten miles south of Makatote.

A camp having been established at Makatote. from which point a regular coach service runs to tho northern railhand, gangs have been sent out in both directions to clear tho hush. Three gangs have been sent over the gorge towards the Manganui-a-te-ao, and four are busy between Makatote and the Waimarino. If they make reasonable progress, the bush should all' he felled on tho northern section by June, and the cuttings should be in hand. The Manganui-a-te-ao viaduct will he 244 ft long and 130 ft in height. Exclusive of the men employed by the contractors for tho ; Makatote viaduct and by carters on tho roads, there are now 800 engaged on the northern section of the railway and tho necessary service roads. Tho Resident Engineer (Mr J. D. LouchA.M.1.C.E.) has the following staff; Mr J.-.W. McEnnis. chief assistant engineer, Raurimu; Mr J. McKenzie, assistant engineer, Oio; Messrs Lucas and Webb, overseers. THE MAKATOTE VIADUCT.

When the Government last June let the contract to Messrs J. and A. Anderson, of Christchurch, tor the construction and erection of tho Makatote viaduct, tho time for completion was •fixed at two years. But as access to the site was only ■-'rovided in January, the firm will probably get tho benefit of the extra six months. . Tho road was opened on January 14th, and on the 25th the first waggon-load of material, railed from Auoldand to Oio, arrived on tho ground. Now about three hundred tons of plant is delivered. Mr Maher, the firm’s foreman, had arrived a few weeks earlier with, a gang of men to clear the ground. A large clearing was made at tho top of the hill for the erection of the workshop, which is now almost complete. It is one hundred yards long, and is equipped with everything in tho way of drilling, planing, and bonding machines. Part of the machinery will bo driven direct from steam pulleys and the remainder from electric motors, the power being generated by the steamengine.

At the top of the hill overlooking the structure will bo erected gantries to carry the 2Jin steel cable, on which all tho iron-work will bo swung out to its place. Tho stretch of cable from gantry to gantry will bo 1000 ft, and the blondin wall weigh 22owt. The biggest lift will be a girder weighing twenty tons. Tho steam winding engine is already in position close to the workshop. In the bed of tho river three hundred feet below, a heavy fluming has been erected to load the water of the Makatote on to the’turbine which is to generate electricity for all the earthworks. There will ho a separate power-house down in tho river-bed to drive tho pumps and lighting, stono-orusher and oemont-mixor. The stone will be obtained from tho river-bed and carried to the crusher on a tramway running along the top of tho fluming. A start was made a fortnight ago excavating for the foundations of the large piers. Two of the four foundations for the largest will require excarations 60ft deep to reach a solid c Ttey will eaoh contain 1200yds of concrete. The viaduct will be nearly 900 ft long, there being five spans of 100 ft, five of 36ft, and five piers of 36ft. The height from tho creek-bed to rail-level will be 260 ft though both longer and higher than the Makohine viaduct, that at Makatote will not be so difficult to build or so costly, because the spans are shorter and the foundation material is safer. At Hakohino the foundations were in papa, and enormous concrete monoliths were necessary. At Makatote the material is much harder. The longest span at Makatote is 100 ft long f t at Makohine was 247 ft. The contract price of the Makatote viaduct is £53,369. The contractors, who are represented by Mr Maher and Mr G. Pascoc (in charge of the workshop), will probably have a hundred men employed on 11,© job before long, and hope to complete the work before tho time expires tKaf by January, 1908. ’ I3 >